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Home My WebLink AboutIEEE Guide to the Installation of Overhead Transmission Line Conductors 1980ve st, “WEE Guide to tie Installation of Cverhead \ransmission Line Conductors \ a a \ \ \ %\ # ee a moe =p sy ley | ‘ | \ . . By a \, 4 ‘* “ Ne es ey v7’ | AZ ” : “ a on ’ a] . \ x J ~ ne j } ‘ iGhed by NS “4 i 4 i } { ay Mi ‘ ~ Necednveneaien dd ey Nw IEEE Std 524-1980 IEEE Guide to the Installation of Overhead Transmission Line Conductors Sponsor Transmission and Distribution Committee of the IEEE Power Engineering Society ©Copyright 1980 by The Institute of Electrical and Electronics Engineers, Inc No part of this publication may be reproduced in any form, < in an electronic retricual syste or otherwise, without the prior written permission of the publisher. Joseph L. Koepfinger, Chairman William E. Andrus C. N. Berglund Edward J. Cohen Warren H. Cook David B. Dobson R. O. Duncan Charles W. Flint Approved December 14, 1978 IEEE Standards Board Ivan G. Easton, Secretary Jay Forster Ralph I. Hauser Loering M. Johnson Irving Kolodny William R. Kruesi Thomas J. Martin John E. May Irvin N. Howell, Jr. Vice Chairman Donald T. Michael Voss A. Moore William S. Morgan Robert L, Pritchard Blair A. Rowley Ralph M. Showers B. W. Whittington £ Foreword (This Foreword is not a part of IEEE Std 524-1980, IEEE Guide to the Installation of Overhead Transmission Line Conductors.) This guide was compiled and written by Kenneth L. Griffing, D. H. Gilliam, William J. Bellerby and James W. Reilly. It includes contributions by persons from many electric utility companies and suppliers. However, because of the diversity of methods employed by different companies, only those methods most commonly used are discussed. Brief examination of the guide will serve to familiarize one with the range and completeness of the information. Terms unique to overhead transmission line construction have been defined. Every effort has been:made to plan and write a guide that will serve as a useful reference. : Members of the Conductor Stringing Equipment Task Group were: J. W. Reilly, Chairman H. W. Adams R. Lemire W. J. Bellerby K. E. Lindsey C. B. Benham W. H. McKinnon W. Caulkins T. O'Teter D. H. Gilliam J. B. Roche L. A. Gravel H. E. Skelton K. L. Griffing C. G. Sparrowe W. Howington J.M. Van Name R. E. Larson A. C. Verock SECTION PAGE WP TEROGUCHION:. 6. so .sc ceive sion ees eco ss wee 6) afebhe 2 Sands 0 Si wicaie ms init as noted as eee 8 7 Pte Seo pe. obese es clalelels eisicfe el wsoncahe oj euslolsieve tuene[a [2 ninig #55 Scent) e/a) = alfeate ria/cii 7 TO Purpose acs Soe eee ee ee eee tsetse cence erent t ae 6 delete eso sain) 7 1.8 Application.......0s.0- see cece e eres erence rar aretcressesessesrc cs 7 2. Definitions and Cross Reference .....----+ eee ceere reeset serrr sss e ste 7 2.1 Definitions and Terminology for Conductor Stringing Equipment .........-.--- 7 2.2 Cross Reference.......-.-+eeeeeereee | eield-allele sie vlelelelele 4 s/¢1elalele.sie|s|«s/ej0 16 9. References: .<..- ee ee eee cea ole ewe te wee meee cclte ee secs te aes eleeisis)* cies 18 Conductor Stringing Methods... 26... eee cece reece reece tree ets tees t esses 18 41 Slack or Layout Method ......---- eee ee eee cece eee tte terre serene 18 4.2 Tension Method ........--- ee eee reece rete ener eres tases sess recess 19 5. Grounding Equipment and Methods... ....----e eee eeeeerrrrrrrrer rss stress 19 BL es Introduction <2). bot fc) fol) fie al elale le wee os cae oleles treteleie cle ss ps o/s sicieie ss 8) °)2 19 5.2 Source of Hazards....... ee ee eee eee eet cette etter rss ress 20 5.3 Protection of Personnel... ...----- sss eee reer eet r tert r rset rst teers 20 5.4. ~ Grounding Devices .... 2... eee ee reece rere teeter neers testes eters ccs es 20 5.5 Grounding System Considerations. .......--+ e+ +e reeere errr tress 20 6. Communications...........eeee ee eee eect rere errr eerste reer eres errs es ss 21 Conductor Reels... 10-222 cece eect e eer eect enter neces eter accccrnc esas 22 71 Reel Types 2.2... eee eer e creer eee ener eceeeereeeeercrrercree sere as 22 7.2 Reel Handling.......--- eee e eee ee eeee Le td del clelell le bp ded Hoare hbo t a 22 8. Special Requirements for Mobile Equipment ......---. eee see eter terete teres 22 B1 ReelStand........---cces eee e eee e eee eee et etre rests steer eee e eee ae 23 8.2 Helicopter.........- eee e cece e eee e tert steer sees n ests ss sree esses 23 8.3 Conductor Bullwheel Characteristics... .-.--- eee e reer erect errs rete 23 8.4. Puller and Tensioner Operating Characteristics ....----+++ ee eerrerrstctecee 24 8.5 Pilot Line Winder Operating Characteristics ..... +--+ ++ +eee seer reer recstete 24 O:| Travelers! bet eal lel tani bert aa elaletolelelefee ie wales pa ec eraaliee spre ate eee 25 9.1 Sheave Diameter.....----- eee cere reer tree errr tert rt reser reser sss 25 9.2 Configuration of Groove... 11+... ee eee ee ere erent errr rss ter erences es 25 9.8 Bearings. .....cc- cece eres c cer ceee eect er cer cersetranccsccers etre sees 25 9.4 Material and Construction..... 0... 22s eer ee eee ctr r ttre s eter sss 27 Be ee eee eer rrey Tae TP ee ares ee 27 96 Electrical Characteristics... 6... --- see ee eee errr reer tre ters terse es 27 9.7 Bundled Configurations. .....--.-. eee cece e terete ttt rrr erste sess sss 27 9.8 Helicopter Travelers ......--+ + sees reer errr errr ster esses sess 28 9.9 Uplift Rollers and Hold Down Blocks... ee eee teeter eee eees 28 9.10 Traveler Suspension. .......-.-+--s sere ere eres rrrrr ster erste esse ss 28 10. Typical Procedures for Stringing Operations... 62... e eee eee rete teeter etree 28 10.1 Pull, Tension, Anchor and Splicing Sites... -- +--+ +++ eer re ttre rrr eter tees 28 10.2 Section Between Snub Structures... 0-2 eee eee cert teeter trees 29 10.3 Conductor Splicing ....... 26. cece eee e ere teeter renters ste seeees 30 10.4 Stringing Procedures ......-- sees eee erect ttt erst rss t sess ss ce es 31 10.5 Sagging Procedures .....--- eee sees eee crete entre t ests sess e reese 35 SECTION PAGE 10.6 Dcadending Precautions ........ 000 eee tee tent e enn e en enes 45 10.7. Clipping Ins. - - -- oe oe re ee eee eee nt mente rete mete net 46 10.8 Damper Installation. ...... 6.0 e eee eee eee eee teen ete e teense 46 10.9 Spacer Installation. .......6 0-0 cee eee eee eee erent tte 46 FIGURES Fig1 Running Ground ......-- 20. e sees eee teeter eee eter nese ress se senses 19 Fig 2 Helicopter Installing Pilot Line. .....+- +++ +e eee ee reer eect tert s etre erste 23 Fig3 Recommended Bullwheel Dimensions ....----++++e+eereeerrersectrsectesees 23 Fig4 Drum Type Puller......--.-- +e - eee reer errr rere rrr Oddie ole etea la leale 24 Fig5 Pilot Line Winder. ...... 2... esse eee rece reser eer e erste etter sees sr ees 24 Fig6 Recommended Sheave Configuration. ..--- +++ essere ereeer testes ss retest 26 Fig 7 Bundle Conductor Traveler with Uplift Roller and Grounds .......-----+eeeeeeee 27 Fig8 Tension Site........ 0. eee eee eee errr e retest nets e eens e esses esses: 29 Fig9 Cradle Block System .......---++ereeceercrese sett rece rt ets e estes se 29 Fig 10 Composite for the Installation of Overhead Transmission Line Conductors.........- 33 Fig 11 Bullwheel Reeving for Right-Hand Lay Conductor. ...---- +++ ese errr reer eres 34 Fig12 Birdcaging ..........0. eee e cece cere eres ttt t teeters sss sess sess 34 Fig 13 Example Application of Clipping Offsets ...-----+++eeeserrrterrrst resents 36 Fig 14 Nomograph for Determining Level Span Equivalents of Nonlevel Spans ......---+--- 37 Fig 15 Nomograph for Determining Control Factor for Conductor Sagging .......----+-++-- 38 Fig 16 Conductor Sagging by Calculated Angle of Sight... 2.2... - eee eee cece etree 39 Fig 17 Conductor Sagging by Calculated Target Method .......---- ee eee cere ere erteee 40 Fig 18 Conductor Sagging by Horizontal Line of Sight... 2.2... 22 ee eee eee eee eee 41 Fig 19 Conductor Sagging for Checking Sag S 1.1... eee eee ee eee eee erent tsees 42 Fig 20 Sagging Thermometer and Container... 2.2... eee eee eee ee eee eee eee eteee 44 TABLES Table 1 Grounding Cable Capacities ... 1.26.2. eee eee eee reer rete ttre reese 20 Table 2 Dimensions of Standard Reels .....-- +--+ eee e ee rerer crete etter streets 22 APPENDIXES Appendix A Travelers or Snub Structure Load Calculation. ......- 2-0 e eee ee eee eters 47 Appendix B_ Efficiency of Travelers During Tension Stringing ....--- +--+ ee errr rere eee 49 Appendix C Recommended Bearing Pressure on Sheave Linings. ....--- +--+ esses eeeree 51 Appendix D All Aluminum 1350 Alloy Conductor Standard Packages....-.----++-e++++e+> 52 Appendix E ACSR Conductors Standard PackageS.... 22. eee cece cece eee rete ee eeeeee 53 Appendix F Drum or Reel Winding ..----+-++eeerr re eretr rr se tres sess tess s sees 55 Appendix G Drum or Reel Capacities... 2... eee eee eee teeter teeter teense 56 IEEE Guide to the Installation of Overhead Transmission Line Conductors 1. Introduction 1.1 Scope. This guide provides general recom- mendations for the selection of methods, equipment and tools that have been found practical for the stringing of overhead trans- mission line conductors and overhead ground- wires. The guide also includes a comprehensive list-of definitions for equipment and tools used in stringing and for stringing terms commonly employed. 4.2 Purpose. The purpose of this guide is to present in one document sufficient details of present day methods, materials and equipment to outline the basic considerations necessary to maintain safe and adequate control of con- ductors during stringing operations. References are given in Section 3 for those desiring more detailed information. Because the terminology used for many hardware items and for many stringing terms varies from place to place, the list of definitions is included to provide correla- tion and clarification of the terms most com- monly employed. 1.3. Application. This guide is broad enough yet specific enough to be applicable to the stringing of overhead transmission conductors of all sizes. Since stringing practices for dif- ferent projects will be strongly influenced by the magnitude and nature of each project and by local circumstances, alternate methods that have been successfully employed are presented. The practices that are described provide for continuous control of the conductor from the initial setup to the ready for service condition. Any legal requirements of national, state or local regulations must, of course, be observed. The approach used within this guide is first to describe in general terms the stringing methods most commonly employed, then the specific requirements of the various tools and equipment used. Finally, the application of the methods and equipment to the process of stringing is described. 2. Definitions and Cross Reference Terminology for equipment and procedures associated with the installation of overhead transmission line conductors varies widely throughout the utility industry. Therefore, the table of definitions (2.1) and cross reference (2.2) have been included to provide a correla- tion between the terminology used in this guide and industry synonyms. Note that the synonyms are terms commonly used, although many are not necessarily good usage and should not be taken as equivalents to the guide termi- nology. Many of the terms have additional meanings and usages which are defined in ANSI/IEEE Std 100-1977, Dictionary of Electrical und Electronics Terms. 21 Definitions and Terminology for Conduc- tor Stringing Equipment anchor. A device that serves as 2 reliable sup- port to hold an object firmly in place. The term anchor is normally associated with cone, plate, screw or concrete anchors, but the terms snub, deadman and anchor log are usually associated with pole stubs or logs set or buried in the ground to serve as temporery anchors. The latter are often used at pull and tension sites. (See anchor log, ANSI/IEEE Std 100-1977.) Synonyms: anchor log, deadman, snub. angle, roll over. For tangent stringing, the sum of the vertical angles between the con- ductor and the horizontal on both sides of the IEEE Std 524-1980 traveler. Resultants of these angles must be considered when stringing through line angles. Under some stringing conditions, such as stringing large diameter conductor, excessive roll over angles can cause premature failure of a conductor splice if it is allowed to pass over the travelers. block. A device designed with one or more single sheaves, a wood or metal shell, and an attachment hook or shackle. When rope is reeved through two of these devices, the assem- bly is commonly referred to as a block and tackle. A set of 4s refers to a block and tackle arrangement utilizing two 4 inch double sheave blocks to obtain four load bearing lines. Similarly, a set of 5s or a set of 6s refers to the same number of load bearing lines obtained using two 5 inch or two 6 inch double sheave blocks, respectively. Synonyms: set of 4s, set of ds, set of 6s. block, hold down. A device designed with one or more single groove sheaves to be placed on the conductor and used as a means of holding it down. This device functions essentially as a traveler used in an inverted position. It is nor- mally used in midspan to control conductor uplift caused by stringing tensions, or at splicing locations to control the conductor as it is allowed to rise after splicing is completed. Synonyms: hold down roller, hold down traveler, splice release block. block, snatch. A device normally designed with a single sheave, wood or metal shell and hook. One side of the shell usually opens to eliminate the need for threading of the line. Commonly used for lifting loads on a single line, or as a device to control the position or direction, or both, of a fall line or pulling line. Synonyms: Skookum, Washington, Western. boatswain’s chair. A seat designed to be sus- pended on a line reeved through a block and attached to a pulling device to hoist a workman to an elevated position. Synonym: bosun’s chair. bonded. The mechanical interconnection of conductive parts to maintain a common. electrical potential. (See bonding, ANSI/IEEE Std 10C-1977.) Synonym: connected. bucket. A device designed to be attached to the boom tip of a line truck, crane or aerial IEEE GUIDE TO THE INSTALLATION OF lift and support workmen in an elevated work- ing position. It is normally constructed of fiberglass to reduce its physical weight, main- ¢- tain strength and obtain good diclectric char-* acteristics. Synonym: basket. bullwheel. A wheel incorporated as an integral part of a bullwheel puller or tensioner to generate pulling or braking tension on con- ductors or pulling lines, or both, through friction. A puller or tensioner normally has one or more pairs arranged in tandem incorporated in its design. The physical size of the wheels will vary for different designs, but 17 in (43 cm) face widths and diameters of 5 ft (150 cm) are common. The wheels are power driven or re- tarded and lined with single or multiple groove neoprene or urethane linings. Friction is ac- complished by reeving the pulling line or conductor around the groove of each pair. bundle, two conductor, three conductor, four -conductor, multiconductor. A circuit phase consisting of more than one conductor. Each conductor of the phase is referred to as a sub- conductor. A two conductor bundle has two subconductors per phase. These may be arranged in a vertical or horizontal configuration. Similarly, a three conductor bundle has three subconductors per phase. These are usually arranged in a triangular configuration with the vertex of the triangle up or down. A four con- ductor bundle has four subconductors per phase. These are normally arranged in a square configuration. Although other configurations are possible, those listed are the most common. Synonyms: twin-bundle, tri-bundle, quad- bundle. cable car. A seat or basket shaped device de- signed to be suspended by a framework and two or more sheaves arranged in tandem to enable a workman to ride a single conductor, wire or cable. Synonym: cable trolley. clamp, cable. A device designed to clamp cables together. It consists of a U bolt threaded on both ends, two nuts and a base and is com- monly used to make temporary bend back eyes on wire rope. Synonyms: clip, Crosby, Crosby clip. clamp, strand restraining. An adjustable circular clamp commonly used to keep the individual strands of a conductor in place and prevent them from spreading when the conductor is cut. am <8 OVERHEAD TRANSMISSION LINE CONDUCTORS Synonyms: cable binding block, hose clamp, rise grip plier clamp. clearance. (1) The condition where a circuit has. been -deenergized to enable work to be performed more safely. A clearance is nor- mally obtained on a circuit presenting a source of hazard prior to starting work. Synonyms: outage, permit, restriction. (2) The minimum separation between two conductors, between conductors and supports or other objects, or between conductors and ground (ANSI/IEEE Std 100-1977), or the clear space between any objects. clipping-in. The transferring of sagged con- ductors from the travelers to their permanent suspension positions and the installing of the permanent suspension clamps. Synonyms: clamping-in, clipping. clipping offset. A calculated distance, mea- sured along the conductor from the plumb mark to a point on the conductor at which the center of the suspension clamp is to be placed. When stringing in rough terrain, clipping offsets may be required to balance the horizontal forces on each suspension structure. conductor. A wire or combination of wires not insulated from one another, suitable for carrying an electric current. It may be, how- ever, bare or insulated (ANSI/IEEE Std 100- 1977). Synonyms: cable, wire. conductor car. A device designed to carry workmen and ride on sagged bundle conduc- tors, thus enabling them to inspect the con- ductors for damage and install spacers and dampers where required. These devices may be manual or powered. Synonyms: cable buggy, cable car, spacer buggy, spacer cart. crossing structure. A structure built of poles and, sometimes, rope nets. It is used whenever conductors are being strung over roads, power lines, communications circuits, highways or railroads and normally constructed in such a way that it will prevent the conductor from falling onto or into any of these facilities in the event of equipment failure, broken pulling lines, loss of tension, etc. Synonyms: guard structure, H-frame, rider structure, temporary structure. deenergized. Free from any electric connec- tion to a source of potential difference and from Sid 524-1980 electric charge; not having a potential different from that of the ground. The term is used only with reference to current-carrying parts that are sometimes alive (energized). (See dead, ANSI/IEEE Std 100-1977.) To state that a circuit has been deenergized means that the circuit has been disconnected from all intended electrical sources. However, it could be elec- trically charged through induction from energized circuits in proximity to it, particu- larly if the circuits are parallel. Synonym: dead. dynamometer. A device designed to measure loads or tension on conductors. Various models of these devices are used to tension guys Or sag conductors. Synonyms: clock, load celi. energized. Electrically connected to a source of potential difference, or electrically charged so as to have a potential different from that of the ground. (See alive, ANSI/IEEE Std 100- 1977.) Synonyms: alive, current carrying, hot, live. equipotential. An identical state of electrical potential for two or more items. explosives. Mixtures of solids, liquids or 4 combination of the two which, upon detona- tion, transform almost instantaneously into other products which are mostly gaseous and which occupy much greater volume than the original mixtures. This transformation generates heat which rapidly expands the gases, causing them to exert enormous pressure. Dynamite and Primacord are explosives as manufactured. Aerex, Triex and Quadrex are manufactured in two components and are not true explo- sives until mixed. Explosives are commonly used to build construction roads, blast holes for anchors, structure footings, etc. Synonyms: Aerex, dynamite, fertilizer, powder, Primacord, Quadrex, Triex. grip, conductor. A device designed to permit the pulling of conductor without splicing on fittings, eyes, etc. It permits the pulling of a continuous conductor where threading is not possible. The designs of these grips vary con- siderably. Grips such as the Klein (Chicago) and Crescent utilize an open sided rigid body with opposing jaws and swing latch. In addition to pulling conductors, this type is commonly used to tension guys and, in some cases, pull wire rope. The design of the come-along (pocket- book, suitcase, four bolt, etc) incorporates a IEEE Std 524-1980 bail attached to the body of a clamp which folds to completely surround and envelope the conductor. Bolts are then used to close the clamp and obtain a grip. Synonyms: buffalo, Chicago grip, come-along, Crescent, four bolt, grip, Klein, pocketbook, seven bolt, six bolt, slip-grip, suitcase. grip, woven wire. A device designed to permit the temporary joining or pulling of conductors without the need of special eyes, links or grips. Synonyms: basket, _ chinese finger, Kellem, sock, wire-mesh grip. grounded. Connected to earth or to some extended conducting body that serves instead of the earth, whether the connection is inten- tional or accidental (ANSI/IEEE Std 100- 1977). ground grid. A system of interconnected bare conductors arranged in a pattern over a specified area and on or buried below the surface of the earth. Normally, it is bonded to ground rods driven around and within its perimeter to in- crease its grounding capabilities and provide convenient connection points for grounding devices. The primary purpose of the grid is to provide safety for workmen by limiting poten- tial differences within its perimeter to safe levels in case of high currents which could flow if the circuit being worked became energized for any reason or if an adjacent energized circuit faulted. Metallic surface mats and gratings are sometimes utilized for this same purpose. When used, these grids are employed at pull, tension and midspan splice sites. (See counterpoise, ground grid, ground mat, ANSI/IEEE Std 100-1977.) Synonyms: counterpoise, ground gradient mat, ground mat. ground, master. A portable device designed to short circuit and connect (bond) a deenergized circuit or piece of equipment, or both, to an electrical ground. Normally located remote from, and on both sides of, the immediate work site. Primarily used to provide safety for personnel during construction, reconstruction or maintenance operations. Synonyms: ground set, ground stick. ground, personal. A portable device designed to connect (bond) a deenergized conductor or piece of equipment, or both, to an electrical 10 IEEE GUIDE ‘SO THE INSTALLATION OF ground. Distinguished from a master ground in that it is utilized at the immediate site when work is to be performed on a conductor or ¢ piece of equipment which could accidentally , become energized. Synonyms: ground: stick, red head, working ground. ground rod. A rod that is driven into the ground to serve as a ground terminal, such as a copper-clad rod, solid copper rod, galvanized iron rod or galvanized iron pipe (ANSI/IEEE Std 100-1977). Copper-clad steel rods are com- monly used during conductor stringing opera- tions to provide a means of obtaining an electrical ground using portable grounding devices. Synonym: ground electrode. ground, running. A portable device designed to connect a moving conductor or wire rope, or both, to an electrical ground. These devices are normally placed on the conductor or wire rope adjacent to the pulling and tensioning equipment located at either end of a sag sec- tion. Primarily used to provide safety for personnel during construction or reconstruc- tion operations. Synonyms: ground roller, moving ground, rolling ground, traveling ground. ground, structure base. A portable device designed to connect (bond) a metal structure to an electrical ground. Primarily used to provide safety for personnel during construc- tion, reconstruction or maintenance opera- tions. Synonyms: butt ground, ground chain, structure ground, tower ground. ground, traveler. A portable device designed to connect a moving conductor or wire rope, or both, to an electrical ground. Primarily used to provide safety for personnel during construc- tion or reconstruction operations. This device is placed on the traveler (sheave, block, etc) at a strategic location where an electrical ground is required. Synonyms: block ground, rolling ground, sheave ground. hoist. An apparatus for moving a load by the application of a pulling force and not includ- ing a car or platform running in guides (ANSI/ IEEE Std 100-1977). These devices are normally designed using roller or link chain and built-in leverage to enable heavy loads to be lifted or pulled. They are often used to deadend a con- ductor during sagging and clipping-in operations and when tensioning guys. Synonyms: chain a “7? OVERHEAD TRANSMISSION LINE CONDUCTORS hoist, chain tugger, Coffing, Coffing hoist. hook, conductor lifting. A device resembling an open boxing glove designed to permit the lifting of conductors from a position above them. Normally used during clipping-in opera- tions. Suspension clamps are sometimes used for this purpose. Synonyms: boxing glove, conductor hook, lifting shoe, lip. hub. A reference point established through a land survey. A hub or POT (point on tangent) is a reference point for use during construction of a line. The number of such points estab- lished will vary with the job requirements. Monuments, however, are usually associated with state or federal surveys and are intended to be permanent reference points. Any of these points may be used as a reference point for transit sagging operations, provided all neces- sary data pertaining to them is known. It is quite common to establish additional temporary hubs as required for this purpose. Synonyms: monument, POT. _ isolated. (1) Physically separated, electrically and mechanically, from all sources of electrical energy. Such separation may not eliminate the effects of electrical induction. (2) An object not readily accessible to per- sons unless special means for access are used (ANSI/IEEE Std 100-1977). joint, compression. A tubular compression fitting designed and fabricated from aluminum, copper or steel to join conductors or overhead ground wires. It is usually applied through the use of hydraulic or mechanical presses. How- ever, in some cases, automatic, wedge, and explosive type joints are utilized. Synonyms: conductor splice, sleeve, splice. jumper. (1) The conductor that connects the conductors on opposite sides of a deadend structure. Synonym: deadend loop. (2) A conductor placed across the clear space between the ends of two conductors or metal pulling lines which are being spliced together. Its purpose then is to act as a shunt to prevent workmen from accidentally placing themselves in series between the two conduc- tors. ladder, rope. A Jadder having vertical synthetic or manila suspension members and wood, fiber- glass or metal rungs. The ladder is suspended 11 Sid 524-1980 from the arm or bridge of a structure to enable workmen to work at the conductor level, hang travelers, perform clipping-in operations, etc. Synonym: Jacobs ladder. ladder, tower. A ladder complete with hooks and safety chains attached to one end of the side rails. These units are normally fabricated from fiberglass, wood or metal. The ladder is suspended from the arm or bridge of astructure to enable workmen to work at the conductor level, to hang travelers, perform clipping-in operations, etc. In some cases, these ladders are also used as linemen’s platforms. Synonym: hook ladder. leader cone. A tapered cone made of rubber, neoprene or polyurethane that is used to lead a conductor splice through the travelers, thus making a smooth transition from the smaller diameter conductor to the larger diameter splice. It is also used at the connection point of the pulling line and running board to assist in a smooth transition of the running board over the travelers, thus significantly reducing the shock loads. Synonyms: nose cone, tapered hose. lifter, insulator. A device designed to permit insulators to be lifted in a string to their intended position on a structure. Synonyms: insulator saddle, potty seat. line, bull. A high strength line, normally synthetic fiber rope, used for pulling and hoisting large loads. line, finger. A lightweight line, normally sisal, manila or synthetic fiber rope, which is placed over the traveler when it is hung. It usually extends from the ground, passes through the traveler and back to the ground. It is used to thread the end of the pilot line or pulling line over the traveler and eliminates the need for workmen on the structure. These lines are not required if pilot lines are installed when the travelers are hung. line, pilot. A lightweight line, normally syn- thetic fiber rope, used to pull heavier pulling lines which in turn are used to pull the con- ductor. Pilot lines may be installed with the aid of finger lines or by helicopter when the insu- lators and travelers are hung. Synonyms: lead line, leader, P-line, straw line. line, pulling. A high strength line, normally IEEE Std 524-1980 synthetic fiber rope or wire rope, used to pull the conductor. However, on reconstruction jobs where a conductor is being replaced, the old conductor often serves as the pulling line for the new conductor. In such cases, the old conductor must be closely examined for any damage prior to the pulling operations. Syn- onyms: bull line, hard line, light line, sock line. line, safety life. A safety device normally con- structed from synthetic fiber rope and designed to be connected between a fixed object and the body belt of a workman working in an elevated position when his regular safety strap cannot be utilized. Synonyms: life line, safety line, scare rope. line, tag. A control line, normally manila or synthetic fiber rope, attached to a suspended load to enable a workman to control its move- ment. line, threading. A lightweight flexible line, normally manila or synthetic fiber rope, used to lead a conductor through the bullwheels of a tensioner or pulling line through a bullwheel puller. Synonym: bull line. link, connector. A rigid link designed to con- nect pulling lines and conductors together in series. It will not spin and relieve torsional forces. Synonyms: bullet, connector, link, slug. link, swivel. A swivel device designed to con- nect pulling lines and conductors together in series or connect one pulling line to the draw- bar of a pulling vehicle. The device will spin and help relieve the torsional forces which build up in the line or conductor under tension. Synonym: swivel. load binder. A toggle device designed to secure loads in a desired position. Normally used to secure loads on mobile equipment. Synonyms: binder, chain binder. off road vehicle. A vehicle specifically de- signed and equipped to traverse sand, swamps, muddy tundra or rough mountainous terrain. Vehicles falling into this category are usually all wheel drive or tracked units. In some cases, units equipped with special air bag rollers having a soft ‘ootprint are utilized. Synonyms: all terrain vehicle (ATV), swamp buggy. overhead groundwire (lightning protection). 12 IEEE GUIDE TO THE INSTALLATION OF Multiple grounded wire or wires placed above phase conductors for the purpose of intercept- ing direct strokes in order to protect the phase conductors from the direct strokes (ANSI/ IEEE Std 100-1977). Synonyms: earth wire, shield wire, skywire, static wire. platform, aerial. A device designed to be attached to the boom tip of a crane or aerial lift and support a workman in an elevated working position. Platforms may be con- structed with surrounding railings, fabricated from aluminum, steel or fiber reinforced plastic. Occasionally, a platform is suspended from the load line of a large crane. Synonyms: cage, platform. platform, lineman’s. A device designed to be attached to a wood pole or metal structure, or both, to serve as a supporting surface for workmen engaged in deadending operations, clipping-in, insulator work, etc. The designs of these devices vary considerably. Some resemble short cantilever beams, others resemble swimming pool diving boards, and still others as long as 40 ft (12 m) are truss structures resembling bridges. Materials commonly used for fabrication are wood, fiberglass and metal. Synonyms: Baker board, D-board, deadend board, deadend platform, diving board. plumb mark. A mark placed on the conduc- tor located vertically below the insulator point of support for steel structures and verti- cally above the pole center line at ground level for wood pole structures used as a reference to locate the center of the suspension clamp. pole, plumb marker. A small diameter, light- weight pole with a marking device attached to one end, having sufficient length to enable a workman to mark the conductor directly below him from a position on the bridge or arm of the structure. This device is utilized to mark the conductor immediately after com- pletion of sagging. Synonyms: marker, offset marker (pole). puller, bullwheel. A device designed to pull pulling lines and conductors during stringing operations. It normally incorporates one or more pairs of urethane- or neoprene-lined, power driven, single or multiple groove bull- wheels where each pair is arranged in tandem. Pulling is accomplished by friction generated against the pulling line which is reeved around te OVERHEAD TRANSMISSION LINE CONDUCTORS the grooves of a pair of the bullwheels. The puller is usually equipped with its own engine which drives the bullwheels mechanically, hydraulically or through a combination of both. Some of these devices function as either a puller or tensioner. Synonym: puller. puller, drum. A device designed to pull a con- ductor during stringing operations. It is nor- mally equipped with its own engine which drives the drum mechanically, hydraulically or through a combination of both. It may be equipped with synthetic fiber rope or wire rope to be used as the pulling line. The pulling line is payed out from the unit, pulled through the travelers in the sag section and attached to the conductor. The conductor is then pulled in by winding the pulling line back onto the drum. This unit is sometimes used with syn- thetic fiber rope acting as a pilot line to pull heavier pulling lines across canyons, rivers, etc. Synonyms: hoist, single drum hoist, single drum winch, tugger. puller, two drum, three drum. The definition and application for this unit is essentially the same as that for the drum puller previously described. It differs in that this unit is equipped with three drums and thus can pull one, two or three conductors individually or simul- taneously. Synonyms: two drum winch, double drum hoist, double drum winch, three drum winch, triple drum hoist, triple drum winch, tugger. puller, reel. A device designed to pull a con- ductor during stringing operations. It is normally equipped with its own engine which drives the supporting shaft for the reel mechanically, hydraulically or through a com- bination of both. The shaft, in turn, drives the reel. The application of this unit is essentially the same as that for the drum puller previously described. Some of these devices function as either a puller or tensioner. pulling vehicle. Any piece of mobile ground equipment capable of pulling pilot lines, pulling lines or conductors. However, heli- copters may be considered as a pulling vehicle when utilized for the same purpose. rack, traveler. A device designed to protect, store and transport travelers. It is normally designed to permit efficient use of transporting vehicles, spotting by helicopters on the line, 13 Sic 624-1980 and stacking during storage to utilize space. The exact design of each rack is dependent upon the specific travelers to be stored. Syn- onym: dollie car. reel stand. A device designed to support one or more reels and having the possibility of being skid, trailer or truck mounted. These devices may accommodate rope or conductor reels of varying sizes and are usually equipped with reel brakes to prevent the reels from turning when pulling is stopped. They are used for either slack or tension stringing. The designa- tion of reel trailer or reel truck implies that the trailer or truck has been equipped with a reel stand (jacks) and may serve as a reel transport or payout unit, or both, for stringing opera- tions. Depending upon the sizes of the reels to be carried, the transporting vehicles may range from single axle trailers to semitrucks with trailers having multiple axles. Synonyms: reel trailer, reel transporter, reel truck. ruling span. A calculated deadend span length which will have the same changes in conductor tension due to changes of temperature and conductor loading as will be found ina series of spans of varying lengths between deadends. running board. A pulling device designed to permit stringing more than one conductor simultaneously with a single pulling line. For distribution stringing, it is usually made of lightweight tubing with the forward end curved gently upward to provide smooth transition over pole crossarm rollers. For trans- mission stringing, the device is either made of sections hinged transversely to the direction of pull or of a hard nose rigid design, both having a flexible pendulum tail suspended from the rear. This configuration stops the conductors from twisting together and permits smooth transition over the sheaves of bundle travelers. Synonyms: alligator, bird, birdie, monkey tail, sled. safety, conductor. A sling arranged in a verti- cal basket configuration, with both ends at- tached to the supporting structure and passed under the clipped-in conductor(s). These devices, when used, are normally utilized with bundled conductors to act as a safety device in case of insulator failure while workmen in conductor cars are installing spacers between the subconductors, or as an added safety mca- sure when crossing above energized circuits. IEEE Std 524-1980 These devices may be fabricated from synthetic fiber rope or wire rope. sag section. The section of line between snub structures. More than one sag section may be required in order to sag properly the actual length of conductor which has been strung. Synonyms: pull, setting, stringing section. sag span. A span selected within a sag section and used as a control to determine the proper sag of the conductor, thus establishing the proper conductor level and tension. A mini- mum of two, but normally three, sag spans are required within a sag section in order to sag properly. In mountainous terrain or where span lengths vary radically, more than three sag spans could be required within a sag sec- tion. Synonym: control span. sheave. (1) The grooved wheel of a traveler or rigging block. Travelers are frequently referred to as sheaves. Synonyms: pulley, roller, wheel. (2) A shaft-mounted wheel used to transmit power by means of a belt, chain, band, etc (ANSI/IEEE Std 100-1977). site, pull. The location on the line where the puller, reel winder and. anchors (snubs) are located. This site may also serve as the pull or tension site for the next sag section. Synonyms: reel setup, tugger setup. site, tension. The location on the line where the tensioner, reel stands and anchors (snubs) are located. This site may also serve as the pull or tension site for the next sag section. Syn- onyms: conductor payout station, payout site, ree] setup. snub structure. A structure located at one end of a sag section and considered as a zero point for sagging and clipping offset calculations. The section of line between two such structures is the sag section, but more than one sag section may be required in order to sag properly the actual length of conductor which has been strung. Synonyms: 0 structure, zero structure. splice, wire rope. The point at which two wire ropes are joined together. The various methods of joining (splicing) wire ropes together include hand tucked woven splices, compression splices which utilize compression fittings but do not incorporate loops (eyes) in the ends of the ropes, and mechanical splices which are made 14 IEEE GUIDE TO THE INSTALLATION OF through the use of loops (eyes) in the ends of the ropes held in place by either compression fittings or wire rope clips. The latter are joined together with connector links or steel bobs and, in some cases, rigged eye to eye. Woven splices are often classified as short or long. A short splice varies in length from 7 to 17 ft (2 to 5m) for %4 to 1% in diameter ropes, respec- tively, while a long splice varies from 15 to 45 ft (4 to 14m) for the same size ropes. splicing cart. A unit- which is equipped with a hydraulic compressor (press) and all other necessary equipment for performing splicing operations on conductor. Synonyms: sleeving trailer, splicing trailer, splicing truck. step voltage. The potential difference between two points on the earth’s surface separated by a distance of one pace (assumed to be 1 m) in the direction of maximum potential gradient (ANSI/IEEE Std 100-1977). This potential difference could be dangerous when current flows through the earth or material upon which a workman is standing, particularly under fault conditions. Synonym: step potential. stringing. The pulling of pilot lines, pulling lines and conductors over travelers supported on structures of overhead transmission lines. Quite often, the entire job of stringing conduc- tors is referred to as stringing operations, beginning with the planning phase and termi- nating after the conductors have been installed in the suspension clamps. stringing, slack. The method of stringing con- ductor slack without the use of a tensioner. The conductor is pulled off the reel by a pulling vehicle and dragged along the ground, or the reel is carried along the line on a vehicle and the conductor deposited on the ground. As the conductor is dragged to, or past, each support- ing structure, the conductor is placed in the travelers, normally with the aid of finger lines. stringing, tension. The use of pullers and ten- sioners to keep the conductor under tension and positive control during the stringing phase, thus keeping it clear of the earth and other obstacles which could cause damage. switching surge. A transient wave of overvoltage in an electrical circuit caused by a switching operation. When this occurs, a momentary voltage surge could be induced in a circuit adjacent and parallel to the switched circuit OVERHEAD TRANSMISSION LINE CONDUCTORS in excess of the voltage induced normally dur- ing steady state conditions. If the adjacent circuit is under construction, switching opera- tions should be minimized to reduce the possibility of hazards to the workmen. target, sag. A device used as a reference point to sag conductors. It is placed on one structure of the sag span. The sagger, on the other struc- ture of the sag span, can use it as his reference to determine the proper conductor sag. Syn- onyms: sag board, target. tensioner, bullwheel. A device designed to hold tension against a pulling line or conductor during the stringing phase. Normally, it consists of one or more pairs of urethane- or neoprene- lined, power braked, single or multiple groove bullwheels where each pair is arranged in tan- dem. Tension is accomplished by friction generated against the conductor which is reeved around the grooves of a pair of the bullwheels. Some tensioners are equipped with their own engines which retard the bullwheels mechani- cally, hydraulically or through a combination of both. Some of these devices function as either a puller or tensioner. Other tensioners are only equipped with friction type retarda- tion. Synonyms: retarder, tensioner. tensioner, reel. A device designed to generate tension against a pulling line or conductor during the stringing phase. Some are equipped with their own engines which retard the sup- porting shaft for the reel mechanically, hy- draulically or through a combination of both. The shaft, in turn, retards the reel. Some of these devices function as either a puller or tensioner. Other tensioners are only equipped with friction type retardation. Synonyms: retarder, tensioner. touch voltage. The potential difference between a grounded metallic structure and a point on the earth’s surface separated by a distance equal to the normal maximum horizontal reach, approximately 1 m(ANSI/IEEE Std 100-1977). This potential difference could be dangerous and could result from induction or fault condi- tions, or both. Synonym: touch potential. tractor, crawler. A tracked unit employed to pull pulling lines, sag conductor, leve] or clear pull and tension sites, and miscellaneous other work. It is also frequently used as a temporary anchor. Sagging winches on this unit are usually 15 Std 524-1950 arranged in a vertical configuration. onyms: cat, crawler, tractor. Syn- tractor, wheel. A wheeled unit employed to pull pulling lines, sag conductor, and miscel- laneous other work. Sagging winches on this unit are usually arranged in horizontal con- figuration. It has some advantages over crawler tractors in that it has a softer footprint, travels faster, and is more maneuverable. Synonyms: logger, sagger, skidder, tractor. transit. An instrument primarily used during construction of a line to survey the route, set hubs and POT locations, plumb structures, determine downstrain angles for locations of anchors at the pull and tension sites, and to sag conductors. Synonyms: level, scope, site marker. traveler. A sheave complete with suspension arm or frame used separately or in groups and suspended from structures to permit the string- ing of conductors. These devices are somet imes bundled with a center drum, or sheave and another traveler, and used to string more than one conductor simultaneously. For protection of conductors that should not be nicked or scratched, the sheaves are often lined with nonconductive or semiconductive neoprene or with nonconductive urethane. Any one of these materials acts as a padding or cushion for the conductor as it passes over the sheave. Traveler grounds must be used with lined travelers in order to establish an electrical ground. Syn- onyms: block, dolly, sheave, stringing block, stringing sheave, stringing traveler. traveler sling. A sling of wire rope, sometimes utilized in place of insulators, to support the traveler during stringing operations. Normally, it is used when insulators are not readily avail- able or when adverse stringing conditions might impose severe downstrains and cause damage or complete failure of the insulators. Synonym: choker: uplift roller. A small single-grooved wheel designed to fit in or immediately above the throat of the traveler and keep the pulling line in the traveler groove when uplift occurs due to stringing tensions. winder, pilot line. A device designed to payout and rewind pilot lines during stringing opera- tions. It is normally equipped with its own engine which drives a drum or a supporting IEEE Std 524-1980 shaft for a ree] mechanically, hydraulically or through a combination of both. These units are usually equipped with multiple drums or reels, depending upon the number of pilot lines re- quired. The pilot line is payed out from the drum or reel, pulled through the travelers in the sag section, and attached to the pulling line on the reel stand or drum puller. It is then rewound to pull the pulling line through the travelers. winder, reel. A device designed to serve as a recovery unit for a pulling line. It is normally equipped with its own engine which drives a supporting shaft for a reel mechanically, hy- draulically or through a combination of both. The shaft, in turn, drives the reel. It is nor- mally used to rewind a pulling line as it leaves the bullwheel puller during stringing operations. This unit is not intended to serve as a puller, but sometimes serves this function where only low tensions are involved. Synonym: takeup reel. 2.2 Cross Reference Synonyms Aerex alive alligator all terrain vehicle (ATV) anchor log Baker board basket basket binder bird birdie block block ground bosun’s chair boxing glove buffalo bullet bull line bull line butt ground cable cable binding block cable buggy cable car cable trolley Guide Terminology explosives energized running board off road vehicle anchor platform, lineman’s bucket grip, woven wire load binder running board running board traveler ground, traveler boatswain’s chair hook, conductor lifting grip, conductor link, connector line, pulling line, threading ground, structure base conductor clamp, strand restraining conductor car conductor car cable car 16 IEEE GUIDE TO THE INSTALLATION OF Synonyms cage cat chain binder chain hoist chain tugger Chicago grip chinese finger choker clamping-in clip clipping clock Coffing. Coffing hoist come-along conductor hook conductor payout station conductor splice connected connector control span counterpoise crawler Crescent Crosby Crosby clip current carrying D-board dead deadend board deadend loop deadend platform deadman diving board dollie car dolly double drum hoist double drum winch dynamite earthwire fertilizer four bolt grip ground chain ground electrode ground gradient mat ground mat ground roller ground set ground stick Guide Terminology platform, aerial tractor, crawler load binder hoist hoist grip, conductor grip, woven wire traveler sling clipping-in clamp, cable clipping-in dynamometer hoist hoist grip, conductor hook, conductor lifting site, tension joint, compression bonded link, connector sag span ground grid tractor, crawler grip, conductor clamp, cable clamp, cable energized platform, lineman’s deenergized platform, lineman’s jumper platform, lineman’s anchor platform, lineman’s rack, traveler traveler puller, two drum puller, two drum explosives overhead groundwire explosives grip, conductor grip, conductor ground, structure base ground rod ground grid ground grid ground, running ground, master ground, master OVERHEAD TRANSMISSION LINE CONDUCTORS Synonyms ground stick guard structure H-frame hard line hold down roller hold down traveler hoist hook ladder hose clamp hot insulator saddle Jacobs ladder kellem Klein lead line leader level life line lifting shoe light line link lip live load cell logger marker monkey tail monument moving ground nose cone O structure offset marker (pole) outage P-line payout site permit platform pocketbook POT potty seat powder Primacord pull puller pulley quad-bundle Quadrex red head ree] setup ree] setup reel trailer Guide Terminology ground, personal crossing structure crossing structure line, pulling block, hold down block, hold down puller, drum ladder, tower clamp, strand restraining energized lifter, insulator ladder, rope grip, woven wire grip, conductor line, pilot line, pilot transit line, safety life hook, conductor lifting line, pulling link, connector hook, conductor lifting energized dynamometer tractor, wheel pole, plumb marker running board hub ground, running leader cone snub structure pole, plumb marker clearance line, pilot site, tension clearance platform, aerial grip, conductor hub lifter, insulator explosives explosives sag section puller, bullwheel sheave bundle, four conductor explosives ground, personal site, pull site, tension ree] stand 17 Synonyms reel transporter reel truck restriction retarder retarder rider structure roller rolling ground rolling ground safety line sag board sagger scare rope scope set of 4s set of 5s set of 6s setting seven bolt sheave sheave ground shield wire single drum hoist single drum winch site marker six bolt skidder Skookum skywire sled sleeve sleeving trailer slip grip slug snub sock sock line spacer buggy spacer cart splice splice release block splicing trailer splicing truck static wire step potential straw line structure ground stringing block stringing section stringing sheave stringing traveler IEEE Std 524-1980 Guide Terminology ree] stand reel stand clearance tensioner, bullwheel tensioner, reel crossing structure - sheave ground, running ground, traveler line, safety life target, sag tractor, wheel line, safety life transit block block block sag section grip, conductor traveler ground, traveler overhead groundwire puller, drum > puller, drum transit grip, conductor tractor, wheel block, snatch overhead groundwire running board joint, compression splicing cart grip, conductor link, connector anchor grip, woven wire line, pulling conductor car conductor car joint, compression block, hold down splicing cart splicing cart overhead groundwire step voltage line, pilot ground, structure base traveler sag section traveler traveler - IEEE Std 524-1980 Guide Synonyms Terminology suitcase grip, conductor swamp buggy off road vehicle swivel link, swivel takeup reel winder, reel target target, sag tapered hose leader cone temporary structure crossing structure tensioner tensioner, bullwheel tensioner tensioner, reel puller, three drum touch voltage ground, structure base three drum winch touch potential tower ground tractor tractor, wheel tractor tractor, crawler traveling ground ground, running tri-bundle bundle, three conductor Triex explosives puller, three drum puller, three drum puller, three drum puller, drum site, pull bundle, two conductor — puller, two drum clamp, strand restraining triple drum hoist triple drum winch tugger tugger tugger setup twin-bundle two drum winch Vise Grip plier clamp Washington block, snatch Western block, snatch wheel sheave wire conductor wire mesh grip grip, woven wire working ground ground, personal zero structure snub structure 3. References [1] Grounding and Jumpering. A. B. Chance Co, Bulletin 9-7208, 1972. [2] HELLSTERN, V. and VAN NAME, J.M. A Study of Effective Temporary Grounding Techniques for Modern Transmission Lines. EEI Pub No 62-49. {[3] WAGNER,C.F. and LLOYD, B. L. Corona Effects on Traveling Waves Determined by Field and Laboratory Tests. Proceedings, International Conference on Large Electric High-Voltage Systems (CIGRE), Paper No 408, 1956. [4] CLAYTON, J. M. and POWELL, R. L. Application of Arresters for Complete Light- 18 IEEE GUIDE TO THE INSTALLATION OF ning Protection of Substations. AIEE Trans- actions, vol 77, Part 3, 1958. [5] Live Line Maintenance Methods. JEEE; Towers, Poles and Conductors Subcommittee of the IEEE Transmission and Distribution Committee, T73 157-5. [6] BONER, C. J. Manufacture and Applica- tion of Lubricating Greases. Robert E. Krieger Publishing Co Inc, 1971 [7] LUMMIS, J. and FISCHER, H. D., dr. Practical Application of Sag and Tension Cal- culations to Transmission Line Design. AIEE 54-501, June 1955. [8] WINKELMAN, P. F. Sag-Tension Compu- tations and Field Measurements of Bonneville Power Administration, AIEE 59-900, 1959. [9] Limitations on Stringing and Sagging Conductors. Working Group of the IEEE Towers, Poles and Conductors Subcommittee of the IEEE Transmission and Distribution Committee, TP64-146. : A. Conductor Stringing Methods Conductor (including overhead groundwire) stringing systems currently employed in the power industry are almost as numerous as the organizations that string conductors. Outlined below are the basic methods currently in use, : but they are invariably modified to accom- modate equipment readily available and the ideas and philosophies of the responsible super- vision. In addition to a description of the various methods being used are comments relative to application and a listing of equip- ment applicable to each method. This list is not all inclusive since, for example, a reel winder would not be necessary as a separate piece of equipment if this function is designed into the puller or tensioner being used, or a loader would not be required if the reel stand were self-loading. 41 Slack or Layout Method. Using this method, the conductor is dragged along the ground by means ofa pulling vehicle or the reel carried along the line on a vehicle and the con- ductor deposited on the ground. The conduc- tor reels are positioned on reel stands or jacks, either placed on the ground or mounted ona transporting vehicle. These stands are designed to support the reel on an arbor, permitting it to turn as the conductor is pulled out. Usually OVERHEAD TRANSMISSION LINE CONDUCTORS a braking device is provided to prevent over- running and backlash. When the conductor is dragged past a supporting structure, pulling is stopped and the conductor placed in travelers attached to the structure before proceeding to the next structure. This method is chiefly applicable to the con- struction of new lines in cases where mainte- nance of conductor surface condition is not critical and where terrain is easily accessible to a pulling vehicle. The method is not usually economically applicable in urban locations where hazards exist from traffic or where there is danger of contact with energized circuits, nor is it practical in mountainous regions inaccessible to pulling vehicles. Major equipment required to perform slack stringing includes reel stands, pulling vehicle(s) and a splicing cart. 4.2 Tension Method. Using this method, the conductor is kept under tension during the stringing progess. Normally, this method is used to keep the conductor clear of the ground and obstacles which might cause conductor sur- face damage and clear of energized circuits. It requires the pulling of a light pilot line into the travelers, which in turn is used to pull in a heavier pulling line. The pulling line is then used to pull in the conductors from the reel stands using specially designed tensioners and pullers. For lighter conductors, a lightweight pulling line may be used in place of the pilot line to directly pull in the conductor. A heli- copter or ground vehicle can be used to pull or lay out a pilot line or pulling line. Where a helicopter is used to pull out a line, synthetic rope is normally used to attach the line to the helicopter and prevent the pulling or pilot line from flipping into the rotor blades upon release. The tension method of stringing is applicable where it is desired to keep the con- ductor off the ground to minimize surface damage or in areas where frequent crossings are encountered. The amount of right of way travel by heavy equipment is also reduced. Usually, this method provides the most economical means of stringing conductor. The helicopter use is particularly advantageous in rugged or poorly accessible terrain. _ Major equipment required for tension string- ing includes reel stands, tensioner, puller, reel winder, pilot line winder, splicing cart and helicopter or pulling vehicle. 19 IEEE Std 524-1980 5. Grounding Equipment and Methods 5.1. Introduction. For any given situation, the bonding together of all equipment and electri- cal grounds in a common array is of major importance. However, such bonding offers no assurance that a hazardous potential will not exist between the bonded items and the earth. It is impractical to design a grounding system precisely around available fault currents or calculated effects. Such a design would require precise knowledge of many variables and result in a different grounding scheme for each location. The degree of grounding protection required for a given construction project is dependent upon the exposure to electrical hazards which exist within the project area. For a project remote from other lines and at a time of low probable thunderstorm activity, minimal grounding requirements are in order. Minimum grounding requirements include bonding and grounding of all machines involved in stringing of the conductor, pulling line or pilot line. In addition, running grounds should be installed on all conductive lines in front of the pulling and tensioning equipment. On the contrary, for a project in a congested area with exposure to numerous parallel lines and crossing situations, and with probability of thunderstorm activity and adverse weather conditions, extensive grounding requirements are called for. Historically, the most significant hazard results from work in proximity to energized lines. Specific procedures for ground- ing are discussed in Section 10. Under any circumstance, in addition to open jumpers, grounding and other protective mea- sures must be employed to ensure reasonable and adequate protection to all personnel. In addition to the grounding system, the best safety precaution is to respect all equipment as if it could become energized. The degree of protection provided for a specific project must be a decision of project supervision based on a clear understanding of the potential hazards [1], [2]. 1 Numbers in brackets correspond to those in the Ref- erences, Section 3 of this guide. IEEE Std 524-1980 Fig 1 Running Ground 5.2 Source of Hazards. Electrical charges may appear on a line due to one or a combination of the following factors: (1) Charges induced on the line by a neigh- boring energized line (2) A fault caused by an accidental contact or flashover between the line and a neighboring energized line (3) Induced static charge due to atmos- pheric conditions (4) An error in which the line is accidentally energized (5) A lightning strike to the line [3], [4] 5.3 Protection of Personnel. The means of pro- viding personnel protection may take several forms. These may include the insulation or isolation of the workmen, provision of an equipotential zone around the workmen, or provision of a low resistance path to ground for induced charges or fault currents. The insulation or isolation of workmen is usually not a practical approach for construction work other than on energized lines with bare hand work procedures and will therefore not be further discussed [5]. The primary method of personnel protection is the establishment of equipotential work zones to limit touch and step voltages to a safe level. This may be ac- complished by the proper use of low resistance shunts and grounding devices. Low resistance paths to ground are employed to limit the dif- ferences in potential between the various pieces of equipment, structures and individual work zones. Despite grounding precautions, the best protection is to respect all equipment as if it could become energized. on IEEE GUIDE TO THE INSTALLATION OF 5.4 Grounding Devices. All grounding devices must be sized to carry the largest fault current likely to be encountered for a time period long enough to allow the line protection system to operate. Grounding devices include personal grounds, master grounds, structure base grounds, running grounds, traveler grounds, ground grids and ground rods. Figure 1 shows a typical transmis- sion type running ground. The clamps selected for grounding cables should be of high quality and have a fault cur- rent capability equal to the cable. They should be capable of clamping positively on the object being grounded, as distinct from being spring loaded only. Table 1 is a listing of common grounding cable sizes with their fault carrying capabilities. Note that cables larger than 2/0 become heavy and might be difficult to handle, but may be necessary for high fault current values. 5.5 Grounding System Considerations 5.5.1 Care of the Grounding Equipment. Most grounding sticks are made of fiber- reinforced plastic and should be protected Table 1 Grounding Cable Capacities* Cable Size Fault Time rms Amperes AWG Cycles Copper Aluminum 15 10 500 6 500 2 30 7500 4600 60 5 300 3 200 15 16 500 10 500 1/0 30 11 500 7500 60 8 000 5 300 15 21 000 13 000 2/0 30 15 000 9 000 60 10 000 6 500 15 26 500 16 500 3/0 30 18 500 11 500 60 13 000 8 000 15 30 000 21 000 4/0 30 21 000 15 000 60 15 000 10 000 15 35 000 25 000 250 kemil 30 25 000 17 500 *Based on 30°C ambient and a total temperature of 175°C established by ICEA for short circuit char acteristic calculations for power cables. Values are approximately 57%% of fusing current for nominal lengths (<30 ft, 10m). Higher values may be used based on tests. Cables should be regularly inspected. See 5.5, Grounding System Considerations. ae OVERHEAD TRANSMISSION LINE CONDUCTORS. from physical damage and properly stored when not in use. Each stick must be inspected each time before use and wiped clean with a dry rag. Inspection should be made prior to use for loose or dirty connections, broken wire strands and seized clamps. Some damaged sticks can be recondi- tioned. Rubber gloves should not be worn when using grounding sticks. . , 5.5.2 Grounding Conditions. Adverse ground- ing conditions (high electrical resistance) will exist in areas of dry sand or gravel and rock. In sand or gravel, rods with extensions, or a cluster of two or more rods bonded together by grounding cables, may be used as a ground source for portable grounding equipment. In rock, a rod or cluster may be employed at the best site within a reasonable distance. Driven grounds are frequently restricted in their capability to effectively limit potential buildup, particularly if high currents are en- countered. Block and running grounds may also be limited by the ground source to which they are connected. In addition to the grounding system, the best protection is provided by treat- ing all devices and equipment as if they are energized. At the same time, the various grounding means should be used to ensure, as far as possible, that the devices and equip- ment are at an equipotential as near ground potential as possible. - The effectiveness of various available ground sources will vary. These sources would include station ground grids, grounded primary circuit neutrals, grounded towers, anchor rods and ground rods. The preferred source must be determined for a particular system or area. Guy wires should not be used as a ground source. 5.5.3 Cleaning of Connections. Since the value of the grounding system depends on a low resistance path, all surfaces to which a grounding clamp is to be applied must be cleaned to ensure proper contact. The use of grub screws in some clamps may reduce the contact area of the clamp and reduce grounding effectiveness. 5.5.4 Ground Application. Grounding cables must be connected to the ground source first, then to the object being grounded. When re- moving grounds, the ground must be removed from the grounded object first and then from the ground source. The object being grounded should not be teased with the ground clamp. 21 Std 624 1380 The clamp must be poised by the object, snapped on quickly and firmly, and tightened. If an arc is drawn, the clamp should not be withdrawn, but kept on the conductor, thus grounding the line. 5.5.5 Ground Grid Application. Where ground grids are deemed necessary, adequate mea- sures must be utilized to ensure effective con- tact with the earth. This may be accomplished by burying the grid conductors or placing metallic grid mats on the ground surface and through the use of ground rods. All grid con- ductors and ground rods must be interconnected and all equipment, structures, anchors, metallic pulling lines, conductors and overhead ground- wires within the area must be bonded to the grid. The area of the grid must be sufficient to enable all equipment to be placed and all work performed within its perimeter. In some instances, particularly in urban situations, it may be desirable to install temporary barriers to restrict access to the grid area. 6. Communications Slack stringing requires a minimum of com- munications. It is desirable to have communi- cation between the pulling vehicle and the personnel at the reel location. Tension stringing requires good communi- cations between the personnel at the tensioner end and those at the puller end and at inter- mediate check points at all times during the stringing operation. During the stringing of bundled conductors with a running board, it is desirable to observe the running board as it passes through each traveler. The running board observer(s) should have reliable com- munications with both pulling and tensioning ends. When following the board from the ground is not practical, this can be accomplished with the aid of helicopters. During helicopter stringing of the pilot line, overhead groundwire or conductor, reliable radio contact with all ground work sites is extremely important. Dual systems of communication, particularly during the actual stringing operation, should be available in case one system fails. TEEE Std 524-1980 7. Conductor Reels 7.1 Reel Types. Reels are supplied by the con- ductor (or groundwire) manufacturer and can either be of the nonreturnable wooden (NR) or the metal returnable (RM, RMT) type. Table 2 shows the standard reel sizes and nominal di- mensions as published by the Aluminum As- sociation, including supplementary footnotes. Gross weight and type of reel can be obtained from the conductor manufacturer. 7.2 Reel Handling. The type and construction of the reel stand used and the type of reel determine the method and tools for handling. Reels are so constructed that they must be IEEE GUIDE TO THE INSTALLATION OF supported either on an axle through the arbor hole or by the reel flange. Returnable metal reels may be supported by a single-tree ar- rangement that clamps to the flange and is lifted from above. When the reels are lifted by an axle supported from above, a spreader bar must be employed to prevent damage to the conductor or reel, or both, by inward pressure on the reel flange. Proper equipment must be available to lift the reels. 8. Special Requirements for Mobile Equipment 8.1 Reel Stand. Reel stands are designed to be used with tensioners to supply the neces- sary back pressure to the conductor. The Table 2 Dimensions of Standard Reels NOMINAL REEL DIMENSIONS ALUMINUM TOTAL WIDTH ASSOCIATION REEL ~ FLANGE DRUM ARBOR HOLE REEL DESIGNATION VOLUME DIAMETER DIAMETER INSIDE OUTSIDE DIAMETER in? (m?) in (m) in (m) in (m) in (m) in (mm) NR 30.22 i 100 | (.182) 30 (.76) 16 (41) 22 (56) | 25 (.64) | 3-3% (76-83) NR 16 800 (.275) 36 (91) 18 (46) 2 (56) | 25 (.64) | 3-3% (76-83) NR 18 000 (.295) 38 (.97) 20 (51) 22 (.56) | 25 (.64) | 3-3% (76-83) NR 29 100 (.477) 42 (1.07) 21 (53) 28 (71) | 32% (83) | 3-3% (76-83) NR 48.28 38 000 (623) 48 (1.22) 24 (61) 28 (71) | 324% (.83) | 3-3% (76-83) NR 60.28 61 900 | (1.014) 60 (1.52) 28 (71) 28 (71) | 32% (.83) | 3-3% (76-83) NR 66.25 76 000 | (1.245) 66 (1.68) 30 (.76) 28 (.71) | 32% (.83) | 3-3% (76-83) RM 66.32 76 900 | (1.260) 66 (1.68) 36 (91) 32 (81) | 38 (.97) | 3-3% (76-83) RM 68.38 99 300 | (1.627) 68 (1.73) 36 (.91) 38 (97) | 4 (1.12) | 3-3% (76-83) RMT 84.36 122 100 | (2.001) 78-84 (1.98-2.13) 42 (1.07) 36 C9) | 43 (1.09) | 5-S% (127-133) RMT 84.45 152 700 } (2.502) 78-84 (1.98-2.13) 42 (1.07) 4s (1.14) | 52 (1.32) | 5-S% (127-133) RMT 90.45 187 000 | (3.064) 83-90 (2.13-2.29) 42 (1.07) 45 (14) | 52 (1.32) | 5-5% (127-133) RMT 96.60 298 600 | (4.893) 90-96 (2.29-2.44) 42 (1.07) 60 (1.52) | 67 (1.70) | 5-5% (127-133) RMT 108.74 422 400 | (6.922) | 102-108 | (2.S9-2.74) 56 (1.42) 74 (1.88) | 83% | (2.12) | 5-5% (127-133) (1) Prefix NR denotes wooden nonreturnable reel, RM metal returnable reel and RMT metal returnable reel with I- beam tires. (2) Reels RM 66.32 and RM 68.38 have flat rims. (3) Reels RMT 84.36, RMT 84.45, RMT 90.45, RMT 96.60 and RMT 108.74 have 3 in J-beam tires. Reels with similar dimensions except without J-beam tires are sometimes used. (4) Pay off equipment for reels NR 48.28 and smaller sho reel width to provide for extension of bolts and for possib uld be a minimum of 2 in wider than the nominal outside le flange distortion. For reels NR 60.28 and larger, either wood or metal, pay off equipment should be not less than 4 in wider than the reel width. (5) Hub reinforcements will be provided for reels NR 60.28 and NR 66.28. (6) Reels are not designed to withstand the forces required for braking during tension stringing operations. (7) Where NR and RM reels are shown as alternatives, RM reels are preferred for more reliable conductor protection. (8) The RMT 108.74 reel is not employed for any packages included in these standards. It is listed in this table, however, because it may be used for large sizes of conductors which may be added in the future. (9) Total reel volume is the volume to the edge of the flange for NR and RM reels and to inside edge of J-beam for RMT reels. 22 Oh LINE C reer. *) OVERHEAD 7.4 stand(s) are selected to accommodate the con- ductor (or groundwire) reel dimensions and gross weight. Some reels are not designed to withstand the forces developed by braking during tension stringing operations. Direct tension stringing from the reel at transmission line stringing tensions should not be attempted. Conductor may be pulled directly from the reel stand when employing slack stringing methods. If the reel stand is not self-loading, a crane, forklift or other suitable equipment is used to load the reel into the stand. 8.2 Helicopter. When pulling lines with a heli- copter (see Fig 2) advantage in contro] and pulling capacity has been achieved with use of special attachment devices which permit Fig 2 Helicopter Installing Pilot Line pulling from the side of the aircraft at a point near the center of gravity. These devices allow Fig 3 Recommended Bullwheel Dimensions 8 Sar 3 SF4E 5° TO I5° - = 7 7 1 I “+ BULLWHEEL DIAMETER (Dp) RESILIENT MATERIAL = '75 70|--—~GROOVE RADIUS (Rg) a | S D = 9 Ww 150 60 Db = R = 9 a w 125 50 LEGEND 8 Cee Dp BULLWHEEL BOTTOM & cho as OF GROOVE DIAMETER w 100 40 - — {+ 7 De CONDUCTOR DIAMETER 7 He eel T ET 2 3 Dg GROOVE DEPTH So rT! ba ems a Helene cond Rg GROOVE RADIUS B -3 LAYERS “= LAYERS OF GROOVE RADIUS 5 @ ALUM.WIRES® MIN. _MAX. w mi 2 1,2 0525 De 1100 De ZI 50 20}! OR2 1025 3 3 0.525De 0.750Dc 5 4 OR MORE 0 525Dc 0.625Dc a Ww GB EXPANDED © ‘ D oOo = 25410 05 1.25 & > = * THE 7 CENTRAL WIRES OF Zz ALL ALUMINUM CONDUCTORS 2 is ARE CONSIDERED THE CORE. 0.5 10 152.0 (INCHES) 1.25 25 3.75 5 ( CONDUCTOR DIAMETER (Dc) CM ) 23 IEEE Std 524-1980 IEEE GUIDE TO THE INSTALLATION OF Fig 4 Drum Type Puller pulling of loads while maintaining normal op- erating attitude of the aircraft, thus increasing pulling capacity. The devices are equipped with quick release mechanisms and are subject to FAA approval. Braided or other nonrotating synthetic rope should be used to connect the line being pulled to the release mechanisms. 8.3 Conductor Bullwheel Characteristics. The depth (Dg) and flare of grooves in the bull- wheels are not critical. Semicircular grooves with depths in the order of 0.5 or more times the conductor diameter and with flare angles the order of 5° to 15° from the vertical have generally been found to be satisfactory. The number of grooves in the bullwheel must be sufficient to prevent the outer layer of wires of multilayer conductors from slipping over underlying layers. The minimum diameter of the bottom of the grooves (Dy) should be in accordance with Fig 3. Tandem bullwheels should be so aligned that the offset will be approximately one-half the groove spacing. For normal conductors having aright hand direction of lay for the outer wires, pullwheels should be arranged so that when facing in the direction of pull, the conductor will enter the bullwheel on the left and pull off from the right side. For any conductors having a left hand direction of lay for the outer wires, the conductor should enter on the right and pull off from the left. This arrangement is necessary to avoid any tendency to loosen the 24 Fig 5 Pilot Line Winder outer layer of strands as the conductor passes over the bullwheels. See Section 10.4.2, Fig 11. The material and finish of the grooves must be such as not to mar the surface of the con- ductor. Elastomer lined grooves are recom- thended for all conductors, but are particularly important for nonspecular conductors. Should a semiconducting elastomer be used for lining the grooves, it should not be relied upon for grounding. Difficulties have been experienced with single v-groove type bullwheels on some multilayer and special construction conductors. These types of bullwheels should only be used with the concurrence of the conductor manufacturer. 8.4 Puller and Tensioner Operating Charac- teristics. The pulling and braking systems should operate smoothly and should not cause any sudden jerking or bouncing of the conduc- tor. Each system should be readily controllable and capable of maintaining a constant tension. Pullers and tensioners may be mounted separately, or in groups, for bundled conductor installation. Separately mounted tensioners for bundled conductors should have central con- trol so as to maintain uniform conductor stress history. The controls should allow the in- dependent adjustment of tension in each con- ductor. This is particularly vital when stringing bundled conductor. Pullers and tensioners should be equipped with tension indicating and limiting devices. Capacity selection of the puller Nay OVERHEAD TRANSMISSION LINE CONDUCTORS and tensioner is dependent upon conductor veight and length to be strung and the stringing vensions. Tensioner bullwheels must be retarded so that conductor tension may be maintained at various pulling speeds. Positive braking systems are required for pullers and tensioners to maintain conductor tension when pulling is stopped. Failsafe type braking systems are recommended. There are basically two types of pulling ma- chines used in the construction of transmission lines being strung under tension. These are defined as bullwheel and drum or reel type pullers. See Fig 4 which shows a drum type puller. Some drum or reel type pullers are available with level wind features to provide uniform winding of the line. Some drum type and all reel type pullers provide easy removal of the drum (or reel) and line to facilitate highway mobility. This feature also provides the advantage of interchangability of drums. The control of payout tension of the pulling line is a desirable feature of many pullers. Mobility of the pullers and tensioners is im- portant to minimize down time between pulls. Also critical are the setup and leveling features of the units. The overhead groundwire tensioner is nor- mally a separate unit from the conductor tensioner, as the requirements are independent of each other. 8.5 Pilot Line Winder Operating Characteristics. Pilot line winders have operating characteristics similar to drum type pullers. They usually have multiple drums to provide pilot lines for several phase or groundwire positions, or both. See Fig 5. These units normally have capability for high speed operation. Retardation. of the drum(s) is desirable in order to provide con- trolled payout of the pilot lines. These units are frequently employed to directly pull in overhead groundwire. 9. Travelers 9.1 Sheave Diameter. It is generally recognized that as diameters are made larger, the follow- ing advantages are gained. (1) The radius of bending of the conductor is increased, so the amount of strain and the amount of relative movement between individ- val wires in the conductor are reduced. This, in turn, reduces the amount of energy required 25 Sid §24-2960 to bend and straighten the conductor as it passes through the travelers. The force and energy required for such bending and straightening retards the passage of the con- ductor in much-the same way as friction in the bearings of the travelers. (2) The bearing pressures between conductor strand layers are reduced, thus reducing poten- tial conductor internal strand damage. This is commonly known as strand notching. (3) The force required to overcome friction in the bearings is reduced because of the greater moment arm for turning. (4) The number of rotations and speed of rotation is reduced, so wear on the bearings and grooves is alleviated. (5) The obvious disadvantages of larger sheaves are cost and added weight. The minimum sheave diameter (D,) at the bottom of the groove as shown in Fig 6 should be satisfactory for typical conductor stringing operations. However, for stringing conductors in excess of approximately 2 miles or over substantially uneven terrain, the recommended minimum bottom groove diameter of sheaves is [20D,. - 4] in ([20D_. - 10] cm) or larger, where D, stands for conductor diameter. In ex- ceptionally arduous circumstances, accurate sagging may sometimes be very difficult with sheaves having diameters -of less than 19D. or 20D¢. 9.2 Configuration of Groove. The minimum radius at the base of the groove (Rg) is recom- mended to be 1.10 times the radius of the con- ductor as shown in Fig 6. Sheaves having a groove radius as discussed above may, with limitations, be used with smaller conductors. The limitations relate to the number of layers of aluminum wires in the conductor. The more layers of aluminum wires, the more important it is to support the conduc- tor with a well fitting groove. The depth of groove (Dg) should be a mini- mum of 25% greater than the diameter of the conductor. The sides of the groove should flare between 15° and 20° from the vertical to facilitate the passage of swivels, grips, etc, and to contain the conductor within the groove, particularly at line angles. 9.3 Bearings. The bearings should preferably be ball or roller type with adequate provisions for lubrication and sealing out contaminants. The IEEE Std 524-1986 IEEE GU)..= 10 THE INSTALLATION OF \S 15° 10 to 2 | 20° ‘ D,(min)—20 D, - 8 inches or 20D,-20 cm except that , Le Oe D, shall not be less than 12 De, Ala Z D,—Sheave diameter at base of groove ote = D,—Conductor diameter R,—Sheave groove radius R,=0.55D, ; D,—Groove depth Number of Layers R D of Aluminum Wires* = : = Minimum _ Maximum Minimum 1 or2 0.55D, 1.1 De 1.25D, 3 0.55D, 0.75 De 1.25D, 4 or more & Expanded Conductors 0.55D. 0.625D, 1.25D_ A sheave designed for a conductor of a given diameter, in accordance with this figure, may be used for stringing conductors of smaller diameters using above table or as follows: Minimum Diameter Conductor That May Be Used in a Sheave Number of Layers Designed for a Conductor of a Larger Diameter in Percent of of Aluminum Wires* the Diameter of the Larger Conductor 1 or 2 50% 3 i 75% 4 or more & Expanded Conductors 87.5% *The 7 central wires of all-aluminum conductors shall be considered as a core. Example: A sheave, with a groove radius of 0.825 inches and a diameter at the bottom of groove of 22 inches, designed for use with a conductor 1.5" in diameter may be used for stringing a 2 layer conductor with a diameter as small as 0.75”. a 3 = 8 z ae a ot yt 100 40 w 8 = 35 a 6 Ro, 4 LAYER 23 7 | > 2 | Ro,1 OR 2 LAYER VDE 8 5 75 30 1 t + 1435 8 5 LA Rg, SLAYER oe 7 br) CY’ Wet “| 7 é ! a << 123° 8 = ef {| i747} i | | Reed 3 & f— u Tl AG + & z 41 az 1025 5 & | r | Min. R i) | uw 50 20 | A Fo s 2 z 4 2 < | 2 a fj et los 2 ¢ 2 : ri eet {3 3 2 is 7 fo SHEAVE DIAMETER] log us Z z 61s z = A — — — GROOVE RADIUS = 25 10 o4 1 Pitsjiitits LLL 10 us 2.0 25 (INCHES) 2s 375 5 625 (cM) CONDUCTOR DIAMETER (Dc) Fig 6 . Recommended Sheave Configuration 26 ~er OVERHEAD TRANSMISSION LINE CONDUCTORS lubricant must be suitable for the temperature ange involved, and where sealed bearings are ot used, care should be taken to ensure subse- quent lubrication with the same type of grease. Mixing of greases of different types (that is, lithium base and calcium base) may cause degradation of the lubricant and subsequent bearing failure [6]. Bearings must have suf- ficient capacity to withstand running or static loads without damage. Proper maintenance is essential. 9.4 Material and Construction. Travelers may be of any suitable material, with due considera- tion to weight. Unlined sheaves for stringing aluminum conductors should be made of aluminum or magnesium alloy and the grooves should have a smooth, polished finish. It is recommended that the manufacturers safe working load, or other identification to enable determination of such load, be permanently displayed on the traveler. 9.5 Lining. While grooves may be unlined or lined, lining with elastomer provides cushioning to increase bearing area and precludes damage to the conductor from scratched or marred groove surfaces. Steel pulling lines are likely to scratch or mar the surface of unlined grooves, so where such lines are to be used in the same groove as conductor, grooves definitely should be lined. It is generally recommended that all sheaves be lined. The elastomer used for sheave linings should be capable of withstanding all anticipated tem- peratures without becoming brittle or develop- ing semipermanent flat areas. It should be sufficiently hard to prevent the conductor from climbing up the side of the groove. Bear- ing pressure limits for sheave linings are further discussed in Appendix C. 9.6 Electrical Characteristics. Neither lined nor unlined travelers should be relied on for ground- ing the conductor being installed. Greased bearings do not provide necessary conduc- tivity and may be damaged by relatively small currents passing from the sheave to the body of the traveler. Semiconductive linings, commonly referred to as conductive linings, tested to date are reported burned with currents as low as 20 mA. The induced electrical charges on conductor and pulling lines, particularly when stringing in the proximity of energized lines, must be 27 Std 524.960 drained off with traveler grounds which bypass the linings or greased bearings, or both. Traveler grounds provide a means to bypass electrically the sheaves and ground the conductor directly to a ground source. 9.7 Bundled Configurations. Bundle conductor type travelers for stringing two or more sub- conductors simultaneously require special con- siderations. When even numbers of conductors are strung, a symmetrical arrangement is used with an equal number of conductors on each side of the pulling line. An independent center sheave is provided only for the pulling line and must be of suitable material to withstand the abrasion of the pulling line. When odd numbers of subconductors are strung, the center one could follow the pulling line in the center sheave. However, this is usually not desirable because of the material of the groove or because of contaminants deposited in this groove by the pulling line, or because of both. Offset type bundle conductor travelers are used which balance the load by properly spacing the even and odd number(s) of conduc- tors on each side of the pulling force. These travelers are directional and should be color- coded; care should be taken to ensure their proper orientation. When multiple conductors are strung in bundled conductor type travelers, reduced horizontal spacing between grooves can result in conductor oscillation, even in very light crosswind too severe to permit satisfactory sagging. (For example, groove spacing of 5.4 conductor diameters permitted sagging of con- ductors in a crosswind condition which re- peatedly prevented sagging with a groove spacing of 2.7 conductor diameters because of very active conductor oscillation.) When stringing multiple conductors around line angles in excess of 5°, bundle conductor travelers are required until the running board passes through the traveler, but should be replaced prior to sagging with single type travelers to provide proper wire length in the clipped-in position. It is desirable during sagging for the horizontal spacing of the sheaves to match the final subconductor spacing to aid in preventing subconductor sag mismatch. Some bundle conductor travelers may be converted to single conductor type travelers. Multisheave bundle conductor type travelers and running boards must be designed to com- IEEE Std 524-1980 plement each other and work in unison. Running boards should only be used to pull in conductors; they should not be used to line up the conductors with an anchor (that is, running boards should not be pulled sideways). Running boards should have their safe working load dis- played. It is recommended that all running boards be proof tested to 50% over the safe working load. During stringing, normal pulling speeds should be maintained when the running board approaches a traveler. 9.8 Helicopter Travelers. Helicopter travelers utilize outrigger arms which guide the pilot line into the throat area of the traveler. These outriggers are usually brightly painted to be easily seen from the air. Spring loaded gates are employed to contain the line. For bundle conductor travelers, additional guides may be utilized to funnel the lines into the proper groove. The design of helicopter travelers should be such that personnel are not required on the structure during placement of the pilot line. After initial placement of the line by heli- copter, normal stringing practices are employed. Helicopter travelers are directional and care must be exercised to orient them properly on the structures. Due to the rotor wash of the helicopter, if the attachment method of travelers does not prevent twisting, yaw bars should be utilized for this purpose. Some standard travelers may be converted to helicopter type by the addition of accessory parts. 9.9 Uplift Rollers and Hold Down Blocks. Up- lift rollers that attach to the traveler or hold down blocks that are separate devices must be used at positions where uplift might occur. See Fig 7. Uplift can occur with the pulling line during the stringing operation, but usually will not happen when the conductor(s) arrive. Hold down blocks that can be removed prior to the arrival of the conductor(s) without stopping the pulling should be used. Uplift devices that attach to bundle travelers are usually directional and are usually positioned toward the pulling end. These devices should have a breakaway feature in the event of fouling of the pulling line or incorrect installation. 9.10 Traveler Suspension. The vertical location of sheaves should be considered for sagging purposes. For simplicity in marking and clipping procedures, it is desirable for the vertical posi- 28 IEEE GUIDE TO THE INSTALLATION OF Fig 7 Bundle Conductor Traveler with Uplift Roller and Grounds tion of the conductor in the sheave to be at the same elevation as when clamped in the final position in the suspension clamp. Clearance required for running boards over the sheaves of the bundle conductor type traveler frequently prevents proper vertical positioning of conductors. The few inches of drop of the conductor below its final position may be unimportant on tangent towers. 10. Typical Procedures for Stringing Operations 10.1 Pull, Tension, Anchor and Splicing Sites 10.1.1 Site Selection. The selection of pull, tension, anchor and splicing sites must consider accessibility, location of deadends, length of conductor to be strung, available conductor and line lengths, puller capacity, snub structure loads, including placement of pullers, tensioners and conductor anchor locations, placement of reel stands, pilot line winder(s), reel winders and the ability to provide an adequate ground- ing system. 10.1.2 Equipment Location. The location of the puller, tensioners and intermediate anchor sites must be selected so that the snub struc- tures are not overloaded. Where possible, a pulling line slope of three horizontal to one vertical from the traveler to the site is con- a Tension Site sidered good practice. Refer to Appendix A for calculation of snub structure loads. It is also necessary that the puller be positioned so that the pulling line enters the machine at a minimum horizontal angle to minimize any possibility of damaging the line. When a bull- wheel type puller is employed, the ree] winder to recover the pulling line is located at the pulling site. The pilot line winder is located at the tension site. The arrangement of the tensioner and reel stands should be such that the lateral angle between the conductor as it approaches the bullwheel and the plane of rotation of the wheel is not great enough to cause the conduc- tor to rub on the sides of the groove. As an example, birdcaging problems were eliminated with large conductors by using a maximum fleet angle of 1.5° from the plane normal to the conductor reel axis and a back tension of approximately 1000 lb (450 N). Problems of birdcaging are normally more acute with large conductors of three or more aluminum layers. 10.1.3 Anchors. Anchors are normally re- quired for holding equipment in place and snubbing conductors against tensions imposed. The type of anchor is dependent upon the soil conditions and sagging and stringing ten- sions. Portable equipment is often used for this purpose, as well as ground type anchors. Slack should be removed from all anchor lines prior to loading to minimize the possibility ‘ of equipment movement or impact loads to the anchors. 29 Cradle Block System 10.1.4 Equipment Grounding. Adequate ground- ing must be established at all sites. The methods required and equipment used will be deter- mined by the degree of exposure to electrical hazards and the soil conditions at the site. All equipment, conductors, anchors and structures within the work area must be bonded together and to the ground source. 10.2 Section Between Snub Structures 40.2.1 Crossing Structures. When crossing roads, highways, railroads, energized lines, etc, some type of supplemental crossing structure must be employed. This can be guard poles erected in football goalpost fashion of suitable height. In some cases, rope nets are strung between the poles to give more positive protec- tion. A system of blocks can also be used to cradle the pulling lines and conductors. This is accomplished with support lines, space lines and load lines to properly locate the special cradle blocks to afford protection should tension be lost during the stringing operation. 10.2.2 Terrain Problems. The terrain must be analyzed to determine if there are areas of impaired ground clearance under stringing tensions. If such areas exist, precautions must be taken to protect the conductor. Locations of conductor or pulling line uplift must also be identified in order that hold down blocks and uplift rollers may be provided. Other unusual terrain features may dictate special considera- tion. 10.2.3 Traveler Installation. Installation of IEEE Std 524-1980 travelers, including finger lines where used, requires consideration of traveler attachment methods and the need for and location of traveler grounds and uplift rollers. For single conductor vertical insulator assemblies, the travelers are normally connected directly to the insulators, and with vee string insulator assem- blies, to the yoke plate. For most bundled conductor lines, the travelers are connected to the yoke plate. With post-type insulators, the travelers are connected to the end of the insu- lators. Where travelers are installed to string through deadend towers, the travelers are normally connected directly to the tower. If substantial line angles are involved, two travelers in tandem may be required to reduce the bend- ing radius of the conductor or the load on each traveler, or both. Where bundled conductor travelers are used at line angle locations of over 5°, it is advisable to change to individual single conductor travelers after the passage of the running board to facilitate accurate sagging. When adequate quantities of travelers are available, it is common practice to install them at the same time the insulators are installed. Under some situations, travelers may be attached to slings or rods in place of the nor- mal insulator assembly. Need for traveler grounds and required loca- tions must be based on the degree of exposure to electrical hazards. When such hazards exist, as a minimum, traveler grounds should be installed at the first and last tower between the tensioner and puller. When stringing in proximity to energized lines, additional grounds shall be installed as required, but at a maximum distance not exceeding two miles. Additionally, grounds shall be installed within a reasonable distance on each side of an energized crossing, preferably on the adjacent structures. Travelers with grounds are usually sensitive to direction and care must be exercised in hanging the travelers. Usually the grounds are to the pulling end. Each traveler with grounds must be connected with temporary grounding sets to provide an electrical connection between the traveler and earth, or to some conductive medium that is at earth potential. Personnel should never be in series with a ground lead. Traveler grounds should have a suitable ground- ing stud located in an accessible position to enable placing and removing the ground clamps, 30 IEEE GUIDE TO THE INSTALLATION OF with hot sticks when necessary. Traveler grounds will also help protect the sheave linings. At the time the travelers are hung, finger lines, when used, should be installed and tied off at the base of the structures. If the heli- copter method of pilot line installation is not to be used, the pilot line could be installed at this time in lieu of finger lines. ‘ 10.3 Conductor Splicing 10.3.1 Conductor Reel Lengths. Standard conductor reel lengths and dimensions are shown in Appendixes D and E. Normally, more than one conductor reel length will be re- quired to obtain the total length of conductor to be strung at one time. Therefore, the con- ductor lengths must be spliced together at the tension site or midspan sites, or both. Regard- less of the site, however, the required equip- ment and basic procedures are essentially the same and applicable to conductors, overhead groundwires and metal pulling lines. 10.3.2 Equipment. The major equipment re-- quired for splicing operations consists of a splicing cart equipped with a hydraulic com- pressor, compression joints, strand restraining clamps, hold down blocks, rope, conductor grips, hoists, ground rods, personal grounds, bonding cables and bare conductor and clamps for a ground grid when it is to be installed. All equipment must have adequate mechanical or electrical capabilities, or both, for the work involved. 10.3.3 Bonding and Grounding of Conduc- tor Ends. It is extremely important that pre- cautions be taken to prevent personnel from accidentally placing themselves in series between two conductors which are to be connected together, or in series to ground with either conductor. Accidents of this type can be pre- vented by providing an equipotential work area, by grounding and placing a jumper across the opening between the ends of the two conductors to serve as a shunt or by a combina- tion of both. . t The following method is recommended when the line being strung might accidentally become energized, or when it is adjacent to parallel, or both, to an existing energized transmission line, or when the possibility of high fault currents exists and the work is to be performed at ground level by personnel in direct contact with the earth. ~~ OVERHEAD TRANSMISSION LINE CONDUCTORS (1) Install a ground grid if the splice is to be made in midspan. Ground grids installed at the pull and tension sites will suffice for splices made at those locations. (2) Bond the splicing cart and all other mobile equipment, such as tractors, which may be holding the conductor ends, to the grid. (3) Bond the two conductors to be spliced to a common ground using personal grounds connected within 10 ft (3m) of each conduc- tor end, then bond the conductor ends directly together using a jumper. (4) Perform all splicing work within the grid perimeter. In lieu of the ground grid, a metallic ground- ing mat may be used. The conductor ends and the mat should be bonded to a common ground. As before, a jumper must be installed directly between the conductor ends. If multiple ground rods are used, they should be bonded together. All splicing work should be per- formed on the mat. If neither the grid nor the mat are used, all splicing work may be performed on an insulated platform. The conductor ends should be bonded to a common ground and directly together with a jumper as before. If multiple ground rods are used, they should be bonded together. As a minimum, regardless of the level of exposure, a system of interconnected ground rods should be used, but the magnitude of potential electrical hazards must be thoroughly considered. 10.3.4 Compression Joint Application. The dies used to compress the compression joint must be of the correct size, and all presses must be made in the proper sequence specified by the manufacturer of the joint. Joint com- pounds that aid electrical contact and preven- tion of corrosion must also be used as specified by the manufacturer. Failure to adhere to these requirements will result in defective splices which in turn may become potential hazards. 10.3.5 Passing Compression Joints over Travelers. The number of sites required for splicing conductors is dependent upon the number of conductor reel lengths required for the total length of conductor to be strung and the method used to join the conductor lengths as they are pulled out. The most common stringing practice avoids pulling compression joints over the travelers. It consists of using woven wire grips to join the conductor lengths at the tension site until the 31 Sid 624-1950 total required length of conductor has been strung. The conductor is then lowered to the ground at each location of the woven wire grips, spliced, and later pulled up to sag. Another stringing practice consists of splicing the conductor lengths together at the tension site with compression joints specifically de- signed to be pulled over travelers. It has an advantage in that all splicing is done at one location, thus reducing the total number of required operations when compared with the previous practice, particularly when ground grids are required. If this practice is to be em- ployed, a preliminary study of the line to be strung should be made to determine the maxi- mum stringing tensions and roll over angles that would be encountered. Compression joint manufacturers should be consulted. “10.4 Stringing Procedures 10.4.1 Installation of Pulling Lines. When finger lines are installed, they are used to pull the pilot line or pulling line through the travelers as it is pulled out. The pilot line, when used, is then pulled back by use of the pilot line winder behind it pulling the pulling line from a reel or drum puller, which can in turn be used to pull in the conductor. The initial pulling out of the pilot line or pulling line is usually done with any vehicle such asa pickup truck or tractor, as appropriate. When helicopter methods are used, the pilot line is first pulled out by the helicopter (or from the helicopter) and directed by the heli- copter pilot into travelers specially designed for this method. This initial line is usually small diameter synthetic rope, but could also be small steel line. This pilot line is then used to pull in the pulling line in the same manner as previously described. 10.4.2 Installation of Conductor. Once the rope pulling lines have been installed and prior to pulling in any conductor or conductive type pulling lines, a running ground must be installed between the reel stand or tensioner for conduc- tor, or puller for pulling line, and the first tower. This ground must be bonded to the ground previously established at the site. Pulling lines are usually pulled in under ten- sion. The pulling iine is then connected to a single conductor through a swivel link, or to * bundle conductors through swivel links and a running board. Swivel links should not be used on a three- strand synthetic pulling line. Pulling lines may IEEE Sid 524-1980 be synthetic fiber or wire rope. When wire rope is used, it is recommended that swaged type be used since it has less tendency to rotate under load, which minimizes most spinning problems. Swaged rope also has a much smoother outer surface. This smoother surface, plus low rotation, minimizes wear on traveler sheaves and bullwheel grooves on pullers. When synthetic pulling lines are used, a no torque rope is recommended to minimize the problems caused by kinking or twisting. This causes accelerated loss of strength of the pulling line, which results in a hazardous condition. A ball bearing swivel link is usually used for the connections between conductors, pulling lines and running boards. Swivel links must be of sufficient rated working load to withstand loads placed on them during tension stringing. They should also be compatible with the travelers being used so they can pass through without spreading or damaging the sheaves. These special line stringing swivel links are clevis type and compatible with woven wire grips and swaged steel pulling lines. It is recom- mended that swivel links not be passed over bullwheels under significant tension since they may be weakened or damaged due to bending. . When reeving the bullwheels of a tensioner with the conductor entering and leaving the wheel from the top facing in the direction of pull, the conductor should enter from the left and leave from the right for right-hand lay (standard for aluminum conductor) and enter from the right and leave from the left for left- hand lay (standard for groundwire). This procedure will avoid the tendency to loosen the outer layer of strands as the conductor. passes around the bullwheels. It is recommended that conductor of only one manufacturer be used in a given pull, and preferably in any given ruling span. This pre- caution will help avoid significantly different conductor sag characteristics. Attachment of the conductor to the pulling line, running board or to another reel of con- ductor to be pulled successively is accomplished by the use of woven wire grips. These grips should be compatible strength-wise and sized as close as possible for the conductor or pulling line on which they are used. Overall diameter of the grip over the conductor or rope should be small enough to pass over the 32 IEEE GUIDE TO THE INSTALLATION OF sheaves without damage to the sheave or its lining and the grip must also be capable of mating with a proper size swivel link. Metal bands should be installed over the grip to prevent it from accidentally coming off and dropping the conductor. The open end of the grip should be secured with two bands. This should then be wrapped with tape to pre- vent accidentally stripping the grip off the conductor if the end were to snag or catch. This is particularly important when these grips are used on pulling lines or between lengths of conductor when moré than one reel is strung. The grips are then passing through the travelers backwards and if the ends are not banded and taped, they could be stripped off. Experience has shown that pulling speed is an important factor in achieving a smooth stringing operation. Speeds of 3-5 mi/h (5-8 km/h) usually provide a smooth passage of the running board or connecting hardware, or both, over the travelers, whereas slower speeds may cause significant swinging of the traveler and insulator-hardware assemblies. Higher speeds create a potential hazard of greater damage in case of a malfunction. The maximum tension imposed on a conduc- tor during stringing operations should not exceed that necessary to clear obstructions on the ground. This clearance should be confirmed by observation. In general, stringing tension of about one-half of the sagging tension is a good criterion. If greater tensions are required, con- sideration must be given to any possible pre- stressing of conductors that may result, based on the tension and time involved. Consideration must also be given to the fact that when long lengths of conductor are strung, the tension at the pulling end may exceed the tension at the tensioner by a significant amount. Differences in tension are caused by the length of con- ductor strung, number and performance of travelers, differences in elevation of supporting structures, etc. (See Appendix B, Efficiency of Travelers During Tension Stringing.) Light and steady back tension should be maintained on the conductor reels at all times sufficient to prevent over-run in case of a sudden stop. It must also be sufficient to cause the con- ductor to lie snugly in the first groove of the bullwheel and to prevent slack in the conductor between bullwheels. It may be necessary periodically to loosen the brake on the reel stand as the conductor is payed off. As the co IEEE Std 524-1980 PULL TO TOWER or 3 TYPICAL ONE-HALF GROOVE OFFSET CONDUCTOR REELS Fig 11 Bullwheel Reeving for Right-Hand Lay Conductor reel empties, the moment arm available to over- come the brake drag is reduced, and the tension therefore rises. This may cause the conductor to wedge into the underlying layers on the reel. IEEE GUIDE TO THE INSTALLATION OF The reel should be positioned so that it will rotate in the same direction as the bullwheels. Loosening of the stranding that often occurs between the reel and the bullwheels of the tensioner is caused to a great extent by coil memory in the conductor. As the conductor is unwound from the reel and straightens out, the outer strands become loose, a condition that is particularly noticeable ina large diameter conductor and can be best observed at the point at which it leaves the reel. As the conduc- tor enters the bullwheel groove, the pressure of contact tends to push the loose outer strands back toward the reel where the looseness ac- cumulates, leading to the condition commonly known as birdcaging. If this condition is not controlled, the strands can become damaged to the extent that the damaged area of conductor must be removed. This problem can be remedied by allowing enough distance between the reel and tensioner to permit the strand looseness to distribute along the intervening length of conductor and simultaneously maintaining enough back tension on the reel to stretch the core and inner strands to sufficiently tighten the outer strands. The_ maximum time conductors may safely remain in the travelers depends on wind induced vibration or other motion of the ductors. Windblown sand can severely damage conductors in a few hours if clearance is less OVERHEAD TRANSMISSION LINE CONDUCTORS than about 10 ft (3m) over loose sand with little vegetation. Damage from vibration at sagging tensions is quite possible and, when required, dampers should be installed promptly. However, at lower tensions generally used for initial stringing, damage to conductors or sheave bearings, or both, is not likely to occur from vibration. Even for travelers having lined sheaves with root diameters 20 times the con- ‘ductor diameter, i i ant to completé conductor strin : ing, plumb marking, oe soon as possi eet erevees occa eam. from weather, particularly wind. Conductor cbould“not beeing 7 averse wens = predicted before the entire sequence can be completed. Subconductor oscillation may occur in bundled conductor lines and tie-down methods, temporary spacers, or other means may be re- quired to prevent conductor surface damage prior to installation of spacers. Temporarily positioning one subconductor above another to prevent conductor clashing is undesirable since different tension history will produce subconductor mismatch unless the tensions are low and duration short enough so that creep is not a factor. Conductor clashing can mar the strands and produce slivers which can result in radio noise generation. If a bullwheel type puller is utilized, the pulling line must be recovered during the pulling operation on a separate piece of equip- ment. This function is usually performed by a ree] winder which is placed behind the puller in an arrangement similar to the reel stand at the tension site. Once the conductor has been pulled into place, one end is normally attached to the structure through a deadend insulator-hard ware assembly or to a previously sagged section of conductor, and the other end_ transferred from the puller or tensioner to the sagging unit. Attachment of the conductor’ to the sagging unit is accomplished by means of a properly designed conductor grip which must be capable of holding, without slipping, full sagging tension with appropriate safety fac- tors. This must take into account possible impact loads which may be encountered as the pulling line wraps on the winch drum as well as over-tension if the conductor is ac- cidentally pulled above desired sag. Extreme caution must be exercised when 35 IEEE Std 524-1980 transferring conductor from one_ holding device to another, or when connecting two conductors to ensure that the conductors are at all times adequately bonded together and to all equipment being used. This is essential to ensure that personnel cannot get in series with two items at different potentials, or with a conductor which could conduct induced potential to a grounded object. jMethods_and_procedures_for_the installation. oO rhea oundwires are the same as those indicated for conductors except that the loads and tensions involved are lighter. Groundwires are commonly pulled with lightweight pulling lines which are installed directly without the use of a pilot line. The groundwire(s) are nor- mally installed prior to pulling the conductors due to their higher location on the structures and to prevent damage to the more easily damaged conductors when pulling ground- wires up through them. 10.5 Sagging Procedures 10.5.1 Sagging and Clipping Offset Theories. Theoretically, conductor sagging is based upon hyperbolic functions describing a true catenary curve [7], [8]. In practice, however, parabolic approximations of the catenary are often utilized. The theory of clipping offsets is based upon the fact that, between snub structures, the total length of conductor at sag in the travelers is equal to the total length of conductor at sag in the suspension clamps [8]. Sags and clipping offsets are interrelated since sag corrections required for computing sags are dependent upon clipping offset com- putations. The application of sags and clipping offsets computed in this manner will produce balanced horizontal forces which will be the same for each structure within the sag sec- tion [9]. Figures 13 through 19 depict a basic analysis for clipping offsets and typical parabolic methods and computations required for sagging conductors. Where greater accuracy or more detailed information is required, see [7], [8], and [9]. 10.5.2 Records and Forms. To assist in an accurate compilation of sag section data, a set of prepared forms should be devised to record accurately all field data, computations, drawing numbers, etc, as soon as they are obtained. Should questions arise while the work is in progress, or at a later date, the availability of IEEE Std 524-1980 IEEE GUID: TU THE INSTALLATION OF Clipping |\pump Offset Conductor in Travelers Conductor in Suspension Clamps Sag Correction (Typ.) See Detail A For Vector Diagram \or Conductor Tension At Troveler "Deadend” Snub Structure ("Zero” Clipping Offset) Suspension See Detail B For Vector —r Diogram Of Conductor Tension At Suspension . oH Clamp Suspension 0 (%-Y,) Suspension VECTOR DIAGRAM Detail A Detail B "Suspension" Snub Structure ("Zero" Clipping Offset) NOTE: H,=H,tW (%-%) Horizontal Tensions Ho Are Equal W = Conductor Wt Stringing Tensions T Are Equal Sagging Tensions T & T' Are Unequal Per Unit Length BASIC THEORY S CONDUCTOR LENGTH IN TRAVELERS= 2 CONDUCTOR LENGTH IN SUSPENSION “CLAMPS. Fig 13 Example of Application of Clipping Offsets 36 OVERHEAD TRANSMISSION LINE CONDUCTORS 4000 3500 3000 2500 2000 1500 1000 900 800 700 600 400 HORIZONTAL SPACING OF SUPPORTS (A) 300 200 100 ~r FORMULAS FOR EQUIVALENT SPAN LENGTH EQUIV. DEADEND SPAN= 2C-A EQUIV. SUSPENSION SPAN=VAC *For spans between a suspension and deadend tower, use suspension span correction. Example: Assume span with A= 1000 ft, B=100 ft if deadend span, correction=10 ft (see above). If suspension span, correction=2.5 ft (see above). Equivalent span=1000 ft + correction. Read chart sag for equivalent span length. EQUIVALENT SPAN CORRECTION (ADD TO HORIZ. SPACING TO OBTAIN EQUIVALENT SPAN LENGTH) Fig 14 Nomograph for Determining Level Span Equivalents of Nonlevel Spans 37 2+ 3 + 44 5 + ~1o=t25s_ 12.5 100 150 37.5 200 50 250 625 300 75 | | z e, $2 az za ge es ee) i a” a D> o * OF SUPPORTS (B) VERTICAL SPACING IEEE Std 524-1980 20 25 30 35 40 45 50 60 70 i 80 ut 100—S—_ 150 —- 200 250 300 350 400 500 Sag is based on parabolic functions. If sag exceeds 5% of span, do not use this chart. [8], [9]. TEEE Std 524-1980 PROCEDURE DETERMINE FROM NOMOGRAPH THE CONTROL FACTOR OF TRANSIT SETUP” USED IN SAGGING THE CONDUCTOR (SEE EXAMPLES ON THE RIGHT) FOR MOST ACCURATE RESULTS IN SAGGING THE CONDUCTOR THIS VALUE OF CONTROL FACTOR SHOULD NOT BE BELOW THE CURVE SHOWN BELOW. IN ALL CASES A CONTROL FACTOR OF 1.00 IS IDEAL (FOR T=1). B 8 8 ras ft CONTROL FACTOR 8 8880 CONTROL FACTOR 2 / $ / Io : 2S. 458.,- oF CONTROL FACTOR = & = 4S -1- (ESE at T= Distonce tronsit is set below conductor support t= Corresponding distance target is set below opposite 4 support. S= Conductor sag determined from stringing charts. { S= Corresponding sag at point of tongency of conductor ond line of sight. BS= Change of sag “S” BS,= Change of sog “S\" Sag is based on parabolic functions. If sag exceeds 5% of span, do not use this chart. [8], [9]- Fig 15 IEEE GUIDE TO THE INSTALLATION OF EXAMPLES soa SS? ng by calculoted ng (See Figure 17) Exomple | When 3 Yorgel se Te400" ongle of sight (See Figure 16) +601 2 tes900' — aviao0.0" s Poe 7 seaor" ‘ Control foctor = 0.99 (From nomogroph) 5 7 Exomple 2. When sogging by horizontel 7 ~~ fine ef sight (See Figure 18) +9 +1 (T-1) = "B" for horizontol fine of sight 2» = 60.0 staal a Control foctor= 0.9! (From nomograph) e 4 « ° S 408 8 z + $ 08 © Exomple 3. When sogging by calculated ¢ 70 -—80 30 100 os FQ langle of sight) + (T= Aton 6-28) @ = Angie of sight. 200 4+@ = When ongle is above horizontal. -@ = When ongie @ below horizontal, B = Vertico! distance between points of support. 300 +B = When support oheod is higher. = B = When support cheod 1s lower. ~}-400 In exomple, @ = +1°40'2I" or ton @ = +0 02920 S00 A= 1400.0 = B= +600 700 . S= 49. 800 Then (T-t) = 14000002920) -(+60.0)= - 19.12 1000 Control foctor = 0.99 (From momogroph) Nomograph for Determining Control Factor for Conductor Sagging : 38 OVERHEAD TRANSMISSION LINE CONDUCTORS + B- METHOD I: Tan B= Test METHOD 2: Ton = Bit sierM) @ = Angle of sight. + @ When angle is obove horizontal. — @ When angle is below horizontal. t = Vertical distance below support to line of sight. (See Figure 17) T = Vertical distance below support for transit. = Sag. run Horizontal distance between points of support — obtained from structure list or plon & profile. B = Vertical distance between points of support — obtoined from plon & profile, tower site data sheets or field meosurement. +B when support ahead is higher. — B when support ahead is lower. M = Determined from curve on Figure 17. ‘ EXAMPLES GIVEN: A = 1400.0° Ss= 491 @ 60°F B= +600' S = 51.2' @ 90°F T= 400! 1 = 5912) @ 60°F 1 = 6376 @ 90°F METHOD 1 METHOD 2 Ton g = T* B-4 Ton g = Bt 2T—-S(2+M) 4 - ° 0°. | Ton Deoer = 9.000 $912 - 002920 Ton Beorr = s0.0+(6 1 OK2)-1S8 1112+ 0 018) - aoasia Zeorr = + 1°40' 21" Ton Bsorr = Fee = 0.02589 Booey = + 1° 2859" Change in angle $ for 5°F = (1° 40 2I"- 19 28° 59" BH) =0° 1 54" Sag is based on parabolic functions. If sag exceeds 5% of span, do not use this chart. [8], [9]. Pcorr = + 1°40" 19" _ 60.0 + (400)2)-(51.2)(2+0.027) _ Tan Bsoer = 1400.0 = 0.02587 Dsocr = + 1° 28° 55" Chonge in ongle @ for S°F = (12 40" 19" 1° 28'55")( $5 )= 08 1" 54" Fig 16 Conductor Sagging by Calculated Angle of Sight 39 TEEE Std 524-1980 IEEE Std 524-1930 : IEEE GUIDE TO THE INSTALLATION OF EXAMPLES GIVEN: 1400.0° 60.0 40.0° 49.1'@ 60°F 51.2'@ 90°F ONADD wenn ‘ 7 METHOD I: 1 = (2v5-vT)* METHOD 1 METHOD 2: t= 2S-T+SM METHOD 4 = Vertical distance below support for target. t = (2VS—VT) T = Vertical distance below support for transit, vT = 6.325 S = Sag. / ; VSqor = 7.007 A = Horizontal distance between structures — obtained from structure VE: list or plan & profile. 2VS coop = 4014 B = Vertical distance between points of support - obtained from plan a t 60°F = 59.12" profile, tower site dato sheets or field measurement. M = Determined from curve below. VSqr = 7155 Baa 2VSsqer = 14310 . CURVE FOR DETERMINING tone = 63.76" VALUE OF “M" Change in “t“ for 5°F For finding value of target setting “t", See Methods 18 2 ft = (6376 - 59.12X5)= 0.77" a above, or angle of sight "SZ" (See Figure 16). . Ratio "R" =(T/S) = T. - M at i 7S) 4VT/S METHOD 2 For checking vclue of sog "S" (See Figure 19). t = 2$-T+SM Ratio “R" = (T/t) - 0.10 + : M = 2+ 2(T/1) — 4avi/t —4 T/S goog * 0.815 mee Meoer = 0.019 t 2S goog = 98.2" teoor = 59.13 ts 0.08 T/Sgoer = 0.781 ‘c Mgoer = 0.027 2 2Sgoer = 102.4" 2 tooee = 63.78" & 0.06 Change in "t" for 5°F = - DS.) = ; =(63.78 59.13)(35)= 0.78 0.04 . | Sag is based on parabolic func- tions. If sag exceeds 5% of span, do not use this chart. [8], [9]. 0.02 0.00 0.4 0.6 0.8 1.0 12 14 1.6 RATIO "R" Fig 17 Conductor Sagging by Calculated Target Method 40 OVERHEAD TRANSMISSION LINE CONDUCTORS Sta 524-1980 10 os T=S(I-B/4S)*= $k T = Vertical distance of transit below lower support for taking level sight. 08 . A = Horizontal distance between points of support- obtained from structure + list or plan & profile. B = Vertical distance between points of support—obtained from plon & profile, tower site data sheets or field measurement. S = Sag. 2 07 { { K= -&) Determined from curve below. \ EXAMPLE a A= 1400.0 B 60.0) s 49.1 @ 60°F S=_51.2 @ 90° FL B/S = 60.0/49.1= 122 @ 60°F | B/S = 60.0/51.2=1.17 @ 90°F ° o K= 0.482 @ 60°F K =0.50! @ 90°F T= (49.1N0.482)=23.66'@ 60°F T= (51.2)(0.501)= 25.65'@ 90°F Change in"T" for 5°F = (2565-23.66)($5)=0.33' "kK" FACTOR ° uo °° > O3 iFor most accurate results use that 02 part of curve drawn in solid line. o.! 0.0 05 1.0 15 20 25 3.0 35 40 RATIO (B/S) ; Sag is based on parabolic functions. If sag exceeds 5% of span, do not use this chart. [8], [9]. Fig 18 Conductor Sagging by Horizontal Line of Sight 41 IEEE Std 524-1980 IEEE GUID® TO THE INSTALLATION O METHOD 1: S= ( = + t ) . 2 yi ™ METHOD 2: S= 2 + 2 5 S = Sag. t = Vertical distance below support for line of sight. = T+B-—Atan @ when angle @ is above horizontal. = T+B+Atan @ when angle @ is below horizontal. T = Vertical distance below support for transit. Do a Vertical distance between points of support— obtained from plon and profile, tower sife dato sheet or field measurement. +B when support ahead is higher. -B when support ochead is lower. Horizontal distance between points of support - obtained from structure list or plan and profile. B = Angle of sight. M Determined from curve on Figure 17. EXAMPLES GIVEN: A = 1400.0' T = 400° B= 60.0' @ = +1°40' 2I"@ 60°F . (Field Measured) METHOD 1 METHOD 2 NOTE: When using Method 2, value of ®T" should lie between 3/4"S"@ 4/3"S" _ vttvt,? T t 1M Ss = ( 2 ) s 2 + > 7B 1 = 40.0 + 60.0- 1400.0 tan 1° 40'2I" 1 = 59.12! = 59.12 1/2 = 29.56" vt = 7.689 T/2 = 20.0° v T = 6.325 M = 0.061 . 061) Seorr = 49.1" Segoe = 20.0 + 29.56 - SS1210.081 ' Seorr = 49-1 Sag is based on parabolic functions. If sag exceeds 5% of span, do not use this chart. [8], [9]- : Fig 19 Conductor Sagging for Checking Sag S 42 OVERHEAD TRANSMISSION LINE CONDUC] ORS such records might greatly assist in providing the answers. 10.5.3 Design Criteria. A complete set of design criteria for the sag section should be available in the field. Included should be structure design data, stringing data, line profiles, conductor and pulling line sag templates, etc. 10.5.4 Equipment. Major equipment required for sagging includes transits (or similar viewing devices), portable radios, conductor thermom- eters, sagging platforms and targets, hand levels, stadia rods, measuring tapes and miscel- laneous marking devices. 10.5.5 Pull Site and Snub Structure Rela- tionship. A pull site should be adjacent to the snub structure whenever possible. However, if the snub structure is a deadend structure, it could be located several spans away. When this occurs, the conductor between the pull site and the snub structure must be slacked down as much as possible at sag completion to minimize prestressing of the conductor. It is not a desir- able situation since the next sag section will include the prestressed conductor together with unstressed conductor. Such a situation should be avoided. 10.5.6 Conductor Uplift. Under certain con- ditions, conductor uplift within a sag section could occur at sag tension. Hold down blocks or uplift rollers, or both, will be required to hold the conductor in the travelers to compen- sate for this condition. 10.5.7 Sag Section Length. A sag section should not exceed 4% mi (7 km), or approxi- mately 20 spans, in length. Exceptions do occur but should be avoided, particularly in hilly or mountainous terrain. Excessive sag section length will usually result in sagging difficulties. 10.5.8 Sag Span Locations. Before sag spans are selected, a scale profile of the entire sag section should be reviewed to provide a com- plete, clear picture of the relationship between the terrain and the conductor. Such a profile is a valuable tool to be used in the selection of the sag spans and may emphasize locations of potential problems. Sag spans should be at or near each end of the sag section. For sag sections over two miles long, additional sag span(s) near the center of the sag section should be utilized. Sag spans - should be the longer, more level spans. If the sag span is not-a level span, it is best if the 43 TEEE Std 524-1980 transit is located at the lower structure since conductor control is increased. Sag spans should also be located on each side of line angle: de 10.5.9 Tension Changes. Tension changes may occur at any point within a stringing sec- tion where a deadend structure is located. The most complicated situation occurs, however, when tension changes divide the stringing sec- tion into three or more separate parts, each of which must be sagged independently of the other. Under these conditions, two or more ruling spans, and hence two or more required tensions, exist within the stringing section. Although the conductor is continuous through- out the entire stringing section, the tension changes may be accomplished by deadending or the correct use of grips and hoists. Deadend structures will always exist at any point where conductor tension changes, but the mere existence of a deadend structure does not always imply a tension change. 10.5.10 Control Factors. When choosing a sagging method, it should be kept in mind that the point of tangency of the line of sight from the transit to the conductor should fall in the middle third of the span. Reference to the profiles will usually give an indication of the best sagging method to use. For example, tall structures on flat terrain and short spans indi- cate that the methods shown in Figs 17 and 18 would probably provide the best control. Hills, long spans and large conductor sag indicate that the method shown in Fig 16 might be best. Fig 15 depicts various nomographs and curves which may be used to ensure that the methods chosen to sag the conductor will provide adequate control. After the sag spans have been selected, they should be field checked for any potential difficulties which might occur during sagging. At the same time, sagging hubs should be established if required, and measurements required for sagging computa- tions should be obtained. Although stopwatch sagging is sometimes used, accuracy-restricts its applica maller conductors and shorter spans than normally found~in_trans- mission work. 10.5.11 Preparation Prior to Sagging. Prepa- rations for performing the mechanics of con- ductor sagging should be completed well in advance of the actual sagging operation. Other- wise, excessive costs and delay can be incurred. IEEE Std 524-1980 vA O- Fig 20 ' Sagging Thermometer and Container When required, sag span transit hubs should be located and staked, transit height reference marks placed on the structures, and sagging platforms and transit mount brackets installed. Sagging thermometers should be installed sufficiently prior to the actual sagging opera- tion to allow temperature stabilization and should be mounted far enough above the ground to avoid the effect of ground heat radiation. Thermometers should be inserted ina container (sometimes a conductor section) to represent the temperature internal to the conductor. See Fig 20. Two thermometers should be used and should be located in the sag spans which are near, or at the ends of the sag section. . The availability of sufficient portable radios should be ensured and, if necessary, transporta- tion should be arranged. All sagging personnel should ensure that they have the proper equipment and sagging data in their possession. The person who controls the sagging should have in his possession a com- plete set of records pertaining to the entire sagging operation. Due to adverse terrain conditions, sagging personnel will not always be able to observe all spans of the sag section. A study of the sag section profile will normally reveal such a situation. If the condition exists, additional help will be required to ensure that the con- ductors are sagging evenly in the blind spans. 10.5.12 Performance of Sagging Operation. After all preparations have been made and all personnel associated with the sagging operation are in position, the person who controls the sag should relay all last minute details to the puller operator. 44 IEEE GUIDE TO THE INSTALLATION OF He should obtain last minute thermometer readings and use the average of the two read- ings adjusted for an estimated increase or de- crease in temperature at sag completion as the temperature for sagging the conductor. This information should be relayed to all persons involved in the sagging. Never sag a conductor to the level of a previously sagged conductor. Sag all conduc- tors based on temperature design criteria only. At the time of sagging conductors, the sag of any given phase should be within six inches of the theoretical value for the existing tempera- ture conditions. The sag of all phases of a circuit should have similar tolerances and direc- tion from theoretical sag. Subconductors within a phase should have tolerances between each other of not over two conductor diameters with a maximum of two inches. When checking sags at a time after original sagging, it must be remembered that creep will increase the sag and greater tolerance limits must be allowed for this and other unavoidable variations. Although it is desirable to check sags as soon as possible, it must be remembered that errors may be introduced during the clipping and deadending processes. Communications and cooperation between the personnel who are sagging and the puller operator, and among the personnel themselves, are essential. The personnel should keep the puller operator constantly informed of the conductor movement, and if bundled con- ductors are being sagged, they should also keep him advised of the state of evenness existing between the subconductors. Conductor is sagged in progressive order from the tensioner end of the sag section to the puller end. Therefore, as the puller operator initiates conductor movement at the puller end, each person in a sag span, progressing from the puller end to the tensioner end, should inform the person who is actually sagging of the conductor movement as it moves through the sag section. Two benefits are derived by this method of communication. First, the person who is actually sagging knows when to expect conductor movement in his sag span, and second, the puller operator knows when he should slow down or stop pulling. Actual conductor sagging is initiated by the person who controls the sag and is first per- formed by the person in the sag span farthest from the puller working with persons who have OVERHEAD TRANSMISSION LINE CONDUCTORS spliced the conductor in the span containing “he anchors for the previous sag. As the con- juctor is slowly released from the anchors,. the person who is sagging should have the puller operator take the slack out of the con- ductor until it is slightly below sag. This condi- tion should be maintained until the conductor is completely released from the hold down blocks. Once the conductor is completely released, it can be pulled to sag. If the conductors being sagged are bundled conductors, they should be brought to sag as evenly as possible. Should one of the subcon- ductors be inadvertently pulled above sag in the sag span, severe difficulties can develop. In this situation, an attempt to slack one sub- conductor of the bundle down to sag usually results in unevenness in all of the other spans. Should this situation occur after an attempt to slack one subconductor down to sag, the sag should be stopped and the entire bundle slacked down below sag and evened. Another attempt to sag the conductors can then be made. Once the first sag span has been brought to sag, the subconductors of the bundle should be checked for evenness, and then the next progressive sag span should be sagged. Uneven- ness in the sag spans in the middle or puller end of a sag.section can usually be corrected by some manipulations of the conductors and under normal conditions will not result in starting the sag over again. Attempts to sag conductor on excessively windy days should be avoided since serious errors can result due to conductor uplift caused by wind pressure on the conductor. Should severe wind conditions occur after a sag is in progress, allowances must be made for conductor uplift or the sag must be stopped. 10.5.13 Techniques for Checking Satisfactory Sag Progression. There are various techniques which are employed to determine if a conduc- tor is sagging correctly. As stated before, con- ductor is sagged progressively toward the puller end of a sag section. As the first sag span comes to sag, the second person to sag should find that the conductor in his sag span is too high. This is to be expected and is normal unless the conductor is excessively high. As the second person slacks his conductor down to sag, the third person should find the conductor too low in his sag span, and so on until the sag is completed. If any of the persons who are sagging do not have the required conditions 45 Sta 524-1980 when the conductor is brought to sag in the preceding sag span, the entire sagging operation should be halted until the trouble is located. If the conditions above are met, satisfactory sag progression is indicated. However, if an attempt to sag any sag span results in serious movement of a previously sagged span, trouble is again indicated, and the sagging operation should be halted until the trouble is located. When the sag is completed, a tension reading should be recorded if a dynamometer has been used. The reading should be very close to the nominal tensions expected. Should the reading deviate excessively from the nominal tensions expected, the trouble should be located and any corrections made before the completed sag is accepted. 10.5.14 Conductor Reaction to Sagging Tensions. The reaction of conductor to ten- sions applied during sagging operations is similar to the wave created by dropping a stone in water. Once the wave is initiated, it con- tinues for some period of time. Similarly, when tensions are applied to the conductor at the puller end of a sag section, the movement of the conductor is initiated at that point, and although the tension may be held constant (puller stops), the movement of the conductor continues toward the other end at a decreasing rate. This movement must be dealt with when sagging conductor. The travelers which are used to string con- ductor are not frictionless and, therefore, can cause problems during a sagging operation. If one or more of the travelers becomes jammed, sagging can become very difficult. A traveler which swings in the direction of the pull may be an indication of a defective traveler. Should unexplainable sagging difficulties occur, the travelers should be checked. Tensions applied to the conductor to overcome sticky or jammed travelers can cause sudden, abrupt movement of the conductor in the sag spans and quickly cause loss of sag, particularly if the conductor is already very close to sag. 5 10.6 Deadending Precautions 10.6.1 Electrical Hazards. The electrical haz- ards that exist when deadending work is being performed are analogous to those that exist during splicing operations. Therefore, precau- tions must be taken to prevent personnel from accidentally placing themselves in series with a potential electrical circuit. IEEE ftd 524-1980 10.6.2 Tension and Pull Sites. Continuity of grounding and bonding must be maintained when conductors or conductive pulling lines, or both, are transferred between pieces of equipment, or between pieces of equipment and anchors. In the majority of cases, it will be necessary to move an existing ground on a conductor or pulling line before it can be transferred. Before removing the existing ground, the person must install his own per- sonal ground to ensure that he will not place himself in series to ground with the conductor or line being transferred. When two conductors or pulling lines, or any combination of them, are to be spliced or connected together in any way, the recom- mendations of 10.3.3 should be followed. 10.6.3 Deadend Structures. Prior to installing or removing deadend jumper on a metal struc- ture, personal grounds must be installed on the conductors on both sides of the intended work area and connected to the structure. If the structure is wood, they must be connected to a common ground source. In some cases, after one end of the jumper has been per- manently attached to one conductor, electrical induction may be so severe that a third personal ground will be required to bond the loose end of the jumper to the other conductor in order that the jumper can be permanently attached. 10.7 Clipping In. The clipping portion of the conductor stringing operation involves the work following sagging and plumb marking of the conductors. This entails removing the conductors from the travelers and placing them ~ in their permanent suspension clamps attached to the insulator assemblies. Clipping begins once the conductor has been brought to sag and is initiated by placing plumb marks on the conductor directly below the insulator attachment points on the struc- tures with a plumb marker pole. This marking is done as soon as possible after reaching sag to minimize the effect of creep and possible movement of the conductor between spans. In rugged terrain, clipping offsets may be used whereby the suspension clamp, rather than being placed at the plumb marks, is offset a calculated distance from the mark to compen- sate for the unevenness of the terrain and to allow the insulator assemblies to hang vertically when all structures have been clipped in. When clipping is being done, care must be exercised 46 IEEE GUIDE TO THE INSTALLATION OF to be certain that the conductors are grounded prior to clipping, despite the fact that the lines being clipped are not attached to any electrical source. This involves placing a personal ground upon the conductor at the location being worked. After the conductors have been marked, personnel lift the weight of the conductors, allowing the travelers to be removed and the suspension clamps, and armor rod if used, to be placed on the conductors. Lifting is nor- mally done by use of a hoist suspended from the structure and a conductor lifting hook which is designed so as not to notch or severely bend the conductors. After placing the suspen- sion clamps on the conductor, the hooks are lowered; thereby placing the weight of the conductor on the suspension clamp and com- pleting the assembly. Where bundled conduc- tors are used, the multiple conductors may be lifted simultaneously by the use of a yoke arrangement supporting the hooks and a single hoist or other lifting means. 10.8 Damper Installation. Dampers are nor- mally placed on the conductors immediately following clipping to prevent any possible wind vibration damage to the conductors which at critical tensions and wind conditions can occur in a matter of a few hours. 10.9 Spacer Installation. Following the clipping sequence of operations for bundled conductor lines, spacers must usually be installed. This is done by placing personnel on the conductors with the use of a conductor car to ride from structure to structure. Depending on the amount of line to be spaced and the equipment available, cars may be hand powered, towed by persons on the ground or in adjacent struc- tures with ropes, or powered by a small engine on the car itself. Care must be exercised to ensure that the concentrated load of the man, car and equipment does not increase the sag sufficiently to cause a hazard from obstruc- tions over which the car will pass. The installa- tion of the spacers on the conductor varies with the type and manufacture of the spacer and is normally done in accordance with the manufacturer’s recommendations. The load of the man, car and equipment should be equally distributed to all subconduc- tors of the phase. This is particularly important at the time each spacer is attached. OVERHEAD TRANSMISSION LINE CONDUCTORS tEEE Std 524-1980 Appendixes (These Appendixes are not a part of IEEE Std 524-1980, IEEE Guide to the Installation of Overhead Trans- mission Line Conductors.) Appendix A Travelers or Snub Structure Load Calculation The following is a method for calculating the actual load on travelers and snub structures when tension stringing. If structures are at the same elevation and there are no angles in the line, only the first and last travelers need to be considered. However, in rough terrain and when angles are encountered, the load at these points should also be calculated. For snub structure loading the weight of insulator assem- blies and travelers must also be considered. A = distance of tensioner or puller from structure height of structure arm from eleva- tion of tensioner or puller sag during stringing operation difference in elevation between points of attachment angle of conductor from tensioner or puller to horizontal i] B D E "ou F° 47 G = angle tangent to conductor and horizontal K° = azimuth angle of departure in line L = length of span Ry horizontal load on traveler Ry = vertical Joad on traveler Rmax = total load on traveler T = line tension Example: Stringing tension is 5000 lb (T) and you locate your tensioner 300 ft (A) from the first structure. Height from the point of attach- ment of the traveler to the elevation of the tensioner is 100 ft (B). The first span is 1000 ft (L) and sag during stringing is to be 50 ft (D). Angle of departure from the lead-in from the tensioner is 16° (K). The difference in eleva- tion from the first to the second structure is 98 ft (E). The resultant load on the traveler is calculated as shown on Page 48. JEEE Sid 524-1980 A=300ft L=1000ft 5B=100ft D=50ft E = 98 ft _B _ E+4D Tan F = rr Tan G= L _ 100 _98+4-50__ 298 Tan F= 359 Tan @=""4900-~ 1000 F=184° G=166° . The lead-in angle is 18.4° from horizontal and the lead-out angle is 16.6°. The traveler will bi- sect the total angle of 35°, actually giving a 17.5° angle on either side. T = 5000 lb K =16° To solve for Ry: ° ° Ry = 2Tsin- 32 Ry = 2+°5000-sin17.5° IEEE GUIDE TO THE INSTALLATION OF Ry = 3000 lb To solve for Ry: Ry = 2Tsin x Ry = 2° 5000°sin 8° Ry = 1390 1b To solve for Rmax: Rmax = V3000° + 1390" Rmax = 3.307 1b Therefore, the total load on the traveler is 3.307 lb. This value is approximate as the above formulas are based on parabolic rather than catenary equations and sag is disregarded between the tensioner and first traveler. How- ever, this method gives slightly less than actual load. 48 OVERHEAD TRANSMISSION LINE CONDUCTORS Std 524-1°5e Appendix B Efficiency of Travelers During Tension Stringing The question of the efficiency of travelers often arises when planning overhead line con- struction jobs. Before this can be determined, the amount of force, holding power or tension just to support the wire in the span must be calculated. For a level span this can easily be done with the following formula. 2 no W = weight per unit length of conductor D = sag (sag during stringing, not final sag) L = span length T, = tension to support wire in span (static condition) Knowing the tension required to support the wire in a static condition, the next considera- tion is the amount of tension needed to pull the wire across the supports, which in this case are the travelers. The additional tension re- quired here is primarily the work to bend the wire, not to overcome the friction on the bear- ings of the travelers. - If a solid round metal bar is bent around a radius, the metal on the inside of the bend must compress and the metal on the outside of the bend must stretch. It takes a consider- able amount of force acting through an ap- preciable distance to bend such a rigid bar. Force acting through a distance is called work. Wire rope, cable, strand or conductor is made much more flexible than a solid bar by taking round wires and forming them into a helix. The greater flexibility of such a structure is due to the fact that the wire at any point on the inside of the bend does not have to com- press, or on the outside of the bend, stretch. Instead, the wire simply slips around the helix so as to adjust for the shortening on the inside and the lengthening on the outside of the bend. However, these wires are pressed together with considerable pressure. The pressure is due to and is proportional to the tension in the cable (the pull on the cable). Thus the slipping of the wire around the helix when the cable is bent is accompanied by considerable friction. 49 Therefore, while it takes a great deal less work to bend a cable than it does to bend a solid bar, still it does involve an appreciable amount of work. Friction is proportional to the tension in the cable. Thus, the higher the tension, the more work is required to bend the cable around a radius. At each point of support as the cable or con- ductor is being pulled, it must bend to the sheave radius of the traveler at the entering side and then must be straightened out again at the leaving side. Thus an appreciable amount of work (or resistance to pull) is developed at each sheave. The amount of work (resistance to pull) is proportional to the tension and is inversely proportional to the diameter of the sheave because it obviously takes more to bend around a smaller arc than around a larger arc. From this it is apparent that the tension be- comes greater as each traveler is passed since this tension builds up progressively at each support. , If we assume 2% loss at each block, then th efficiency is 98% at each support. To solve for the total loss or the total efficiency, the number of travelers must be an exponent of the efficiency. The efficiency will vary depend- ing on the size of the wire, size of the block, and other factors discussed above. Efficiency at 98% is used as representative under nor- mal conditions encountered. From this, if the initial tension before en- tering the first sheave T,, and the final tension after passing over N number of sup- ports = Trax, then: Tmax = —2 mex 0.98N where ; T, = tension to support first span 0.98 = the efficiency at each traveler N =number of supports Example: D = 50 ft (sag in ft during stringing) WwW = 2 lb (weight of conductor per ft) L = 1000 ft (span length in ft) Std 524-1980 T, = tension to support first span N = 8 (number of supports) 0.98 = assumed efficiency at each traveler Tmax = tension to pull conductor oe WL? _ 2: 1000? 8D 8-50 T, = 5000 lb, Ty 5000 5000 then Tmax = = = ——— =. 5877 lb This formula, explanation and example are 50 IEEE GUIDE TO THE INSTALLATION OF published in this form as a guide. Many factors affect the value being sought. This is an accept- able figure in most instances. In the case of actual varying field conditions encountered, an allowance should be considered. Many variables will affect the assumed 98% efficiency of the travelers. Should very small sheaves be used, the efficiency of the travelers will be much less. On the other hand, cases of large sheaves, over 20 times conductor di- ameter at bottom of groove, have resulted in efficiency of over 99%. This is important as it must be considered in the selection of pulling and tensioning equipment and pulling lines. he ‘Wea OVERHEAD TRANSMISSION LINE CONDUCTORS Std 524-1980 Appendix C : Recommended Bearing Pressure on Sheave Linings Considering bearing pressure between con- ductors and stringing sheaves, it is to be noted that the pressure per unit of length between the conductor and sheave groove is a function of the tension (T) in the conductor and the di- ameter of the sheave to the bottom of the groove (D,) and the diameter of the conductor (D,). The pressure is independent of the angle of radial contact around the sheave and the resulting load on the traveler. The bearing pres- sure is therefore expressed by the following equation: 3T DD, " bearing pressure " P P T conductor tension D, , = diameter of sheave to bottom of groove D, = diameter of conductor or pulling line Limits or guidelines for conductors have been 500-700 for lined sheaves, less for unlined ones. To obtain reasonable wear on sheave linings maximum allowable unit bearing pres- sures for steel pulling lines is 2000 for Neo- prene, 3500 for Urethane. Examples: T = 12000 lb for pulling line T = 6000 lb for each conductor D, = 24 in (28 in sheave, 24 in bottom of groove diameter) 0.625 in (diameter of pulling line) 1.502 in (diameter of conductor) 3 + 12000 24 - 625 2388 representing unit bearing pressure for the 5/g in OD pulling line 3 - 6000 24 + 1.502 && iow uv oY 1 tl 500 representing unit bearing pressure for the 1.502 in OD conductor 51 IEEE Std 524-1980 IEEE GUIDE TO THE INSTALLATION OF . Appendix D All Aluminum 1350* Alloy Conductor Standard Packages : size No **| Conductor Rated | Wr Per | Wt Per | Standard Packaging Gas IStrands} of Diameter Suength | 1000 ft | km bon Weight or sign _[eemit Timm?) Layers Vinches | (mm) |b 1 op 1b. op ft Orchid 636 | 322| 37 | 918 | 23.32 | 11400 | 598.9 | s88.4] RMT 84.45 | 7400 | 3355 | 12.400 | 3780 NR 66.28 | 3.700 | 1.680 | 6,200 | 1890 RM 68.32 | 3.700 | 1.680 | 6200 | 1890 RM 68.38. | 3.700 | 1.680 | 6.200 | 1890 NR 48.28 | 1850 sso | 3100 | 945 Violet 71551 363] 37 | 2 | .974 | 24.78 | 12.800 | 672.0 | 1000 | RMT 84.45 | 7400 | 3.355 | 11020 | 3 360 ; NR 66.28 | 3700 | 1,680 | $510 | 1680 RM 68.32 | 3.700 | 1680 | $510 | 1680 RM 68.38. | 3.700 | 1680 | 5.510 | 1 680 | | NR 48.28 | 1850 840 | 2,755 | - 840 Arbutus 795 403 3x” 2 1.026 26.06 13 900 746.4 in RMT 84.45 7 400 3355 9 920 3025 NR 66.28 3700 1 680 4960 1510 RM 66.32 3 700 1 680 4960 1510 RM 68.38 | 3700 | 1680 | 4,960 | 1510 | 7 NR 48.28 | 1.850 840 | 2480 755 Lilac 79s | 403 | 6: | 3 [1.028 | 2611 | 14300 | 746.8 | 1inr | RMT 90.45 | 9760 | 4.425 | 13080 | 3 985 RM 68.38 4 880 2215 6 540 1995 Magnolia oss | 483] 37 | 2 [1.128 | 2855 | 16.400 | 895.8 | 1333 | RMT 8445 | 7400 | 3355 | 8.260 | 2520 NR 66.28 3.700 1 680 4,130 1 260 RM 66.32 3.700 1 680 4.130 1 260 RM 68.38 | 3,700 | 1680 | 4,130 | 1 260 | NR 48.28 1850 840 2 065 630 Goldenrod 954 483 61 3 1.126 28.60 16 900 896.1 | 1333 RMT 90.45 9760 4425 10 900 3320 | rm 68.38 | 4880 | 2215 | 5450 | 1 660 Bluebell 1033.5 $24 x 2 1.170 29.72 17 700 9710 144 RMT 84.45 7 400 3355 7 630 2325 NR 66.28 | 3.700 | 1.680 | 3815 | 1 165 RM 66.32 3.700 1,680 3815 1165 RM 68.38 | 3.700 | 1680 | 3185 | 1 165 NR 48.28 1850 840 1910 580 Larkspur 1033.5 S24] 61 3 1.172 29.77 18 300 970.7 1444 RMT 945 9 760 4.425 10 060 3 065 RM 68.38 4 880 2.215 5 030 1535 Mangold 1na3 Sos} 61 3 1.216 30.89 19 700 1045 1555 RMT 90.45 9 760 4425 9 0 | 2 845 RM 68.38 4 880 2215 4670 1425 Hawthom 1192.5) 604) 61 3 1.258 31.95 21 :100 mnie 1665 RMT 90.45 9760 4425 8720 2 660 RM 68 38 4 880 2215 4 360 1330 Narcissus | 1272 | 685] 61 | 3 | 1.300 | 33.02 | 22.000 | 1198 1777 | RMT 90.45 | 9760 | 4.425 | 8.170 | 2,490 RM 68.38 | 4.880 | 2.215 | 4085 | 1.245 Columbine | 1351s} 68s} 61 | 3 | 1.340 | 34.04 | 23400 | 1269 rseg | RMT 90.45 | 9760 | 3.425 | 7690 | 2345 | | RM 68 38 4.880 2 215 3 845 1,170 Camation | 1431 | 728] 61 | 3 | 1.379 | 35.03 | 24300 | 1344 1999 | RMT 90.45 | 9760 | 4425 | 7270 | 2215 _| RM 68.38 4 880 2215 3.635 1110 Gladiolus 1510.5) 76S} 61 3 1.417 35.99 25 600 419 2110 RMT 90.45 9760 4425 6.880 2095 RM 68.38 4 880 2215 3.440 1 050 Coreopsis 1890 806] 61 3 1.454 36.93 2? 000 1493 2222 RMT 90.45 9 760 4425 6 540 1995 RM 68.38 | 4880 | 2215 | 3270 | 995 Jessamine 1750 887) 61 3 1.525 38.74 29 700 1643 2445 RMT 90.45 9 760 4425 5 940 | 1810 | | _| RM 68.38 4 880 2215 2 870 905 | 4. Cowslip 2000 voi] cu 4 1.630 41.40 34 200 1876 2793 RMT 90.45 9 100 4 x0 | 4850 jt 480 Sagebrush | 2250 | 11so] 91 | 4 | 1.729 | 43.92 | 37 700 | 2132 ai7a | RMT 90.45 | 9100 | 4130 | 4270 | 1300 Lupine 2500 1267] 91 4 1.823 L 46.30 41 900 | 2368 | 3827 | RMT 90.45 | 9 100 4130 3.840 1170 ‘Alloy 1380 was formerly designated as EC The number of alummmum layers does not include the 7 central wires which are considered as a core. () Denote approximate value : 52 OVERHEAD TRANSMISSION LINE CONDUCTORS Std 524-1980 Appendix E ACSR Conductors Standard Packages Cat ee ee ae oe eo = Word AUstl | : Design Weight Length kemil_[(mm?) vers Finches | (mm) Ib tb (kg) 1b. (key ft im Kingbird 636 | 322 Jig | 2 940 | 23.88 | 15700 | 691 | 1027 | RM 66.32 | 4160 | 1.885 | 6,020 | 1.835 NR 66.28 4160 1 885 6.020 1 835 RM 68.38 |" 4.160 | 1.885 | 6020 | 1.835 NR 48.28 | 2.080 | 935 | 3010 | 91s : NR 42.28 | 1.385 | 620 | 2005 | 610 Rook 636 | 322/247 | 2 | 977 | 24.82 | 22.000 | s19 | 129 | emt 83.36 | 6550] 2.970 | 8000 | 2.110 RMT 84.45 | 6550 | 2970 | 8.000 | 2440 [ NR 60.28 | 3275 | 1485 | 4000 | 1.220 Grosbeak | 636 | 322/267 | 2 | .990 | 25.15 | 25200 | 875 | 1302 | RMT 84.36 | 7590 | 3435 | 8670 | 2685 RMT 84.45 | 7.590 | 3435 | 8670 | 26485 _| NR 60.28 | 3795 | 1720 | 4335 | 1320 Egret 636 322 | 30/19] 2 1.019 28.88 31 500 988 1470 RMT 84.45 9 860 3470 9 980 300 RM 66.32 | 4930 | 2235 | 4990 | 1520 NR 66.28 4930 4 990 1 S20 RM 68.38 | 4.930 4990 | 1520 Flamingo | 666.6} 338 [24/77 | 2 | 1.000 | 25.40 | 23700 | 859 | 1277 | RMT 84.36 | 6.550 7.630 | 2325 RMT 8445 6.550 297 7.630 2328 NR 60.28 3.275 1.485 3.815 1.165 Starling 715.5} 363 }26/7 | 2 | 1.081 | 2670 | 28 400 985 1466 | RMT 84.36 | 7590 | 3435 7.710 | 2.380 RMT 84.45 | 7.590 | 3.435 | 7710 | 2.350 NR 60.28 3.795 1720 3.855 117s Redwing 715.5 363 | 30/19 2 1.081 27.46 34 600 wat 1653 RMT 84.45 9.860 4470 8880 | 2705 RM 66.32 4.930 2235 40 1.355 NR 66.28 4.930 235 4440 1355 4 al, fel RM 68.38 | 4930 | 2.235 | 4.430 | 1.355 Cuckoo: 795 403 | 24/7 2 1.092 27.74 27: 900 1024 1822 RMT 84.36 6.550 2.970 6.400 1 950 RMT 84.45 6 550 2970 6 400 1950 i NR 60.28 | 3275 | 1485 3.200 978 Drake 795 403 | 267 2 1.108 28.14 31 500 1094 1628 RMT 90.45 11 380 £160 10 400 3.170 RMT 84.36 7 590 3445 6.940 2.018 RMT 84.45 7 590 3445 6940 2211S : NR 60.28 3795 1,720 3 470 | 1.069 t Tern 795 | 403 |45/77 | 3 [1.063 | 27.00 | 22100 | 896 | 1333 | RMT 90.45 | 10.750 | 4875 | 12.000 | 3 660 RM 68.38 5.375 2440 6,000 1 830 NR 60.28 3.585 1625 4900 1 220 Condor 795 403 | 54/77 3 1.093 27.76 28.200 1024 1524 RMT 90.45 11,800 5350 11 $20 3510 RM 68.38 5 900 2.675 5.760 1758 Mallard 795 403 | 30/19] 2 1.140 28.96 38 400 1235 1838 RMT 84.45 9.860 4470 7 980 2430 RM 66.32 | 4930 | 2235 | 3.990 | 1215 NR 06.28 4.930 2 235 3 990 12s RM 66.28 | 4930 | 2235 | 3990 | 1.215 Canary 900 456 | 547 3 1.162 29.51 31.900 11s9 1725 RMT 90.45 11 800. 5 350 10 180 3105 RM 68.38 5 900 2 675 5 090 1.550 Rail 954 483 |45/7 | 3 [1.165 | 29.59 | 25900 | 1.075 | 1600 | RMT 9045 | 10750 | 4.875 | 10,000 | 3.050 RM 68.38 $375 2 440 5 000 1,525 NR 60.28 3.585 1.625 3.335 1,015 Cardinal 954 483 [54/7 | 3 | 1.196 | 30.38 | 33800 | 1.229 1829 | RMT 90.45 | 11,800 | 5.350 | 9,600 | 2.925 RM | 68.38 | 5900 | 2.675 | 4.800 4S Onolan 1033.5] $24 |45/7 3 4.212 30.78 27.700 1164 1734 RMT 90.45 10,750 4875 9 230 loss RM 68.38 5375 2440 4615 1 405 NR 60.28 | 3585 | 1.625 | 3075 | 935 Curlew 1033.5] 524 |s4/7 | 3 | 1.244 | 31.60 | 36600 | 1330 | 1981 | RMT 90.45 | 11800 | 5,350 | 8870 | 2705 RM 68.38 | $900 | 2.675 | 4435 | 1350 53 pe IEEE Std 524-1980 IEEE GUIDE TO THE INSTALLATION OF fe [ No Conductor Rated | wr Per | We Per aay Standard Packaging Code Size strands} of Diameter Suength | 1000 ft | km ee! Word AUst Design Lenath kemil [(mm*) Layers [inches [_(mm) 1b 1b (ep) ft im) Blucjay m3 564 45/7 3 1.259 ; 31.98 29 800 1255 1868 RMT W4S 10 750 4 875 8 570 2610 : RM 68.38. | 5.375 | 2440 | 4285 | 1 305 NR__60.28 | 3585 | 1625 | 2.855 | 870 Finch ina | 564 [sano] 3 |4.293 | 32.84 | 39100 | 1431 | 2130 | RMT 9045 | 11720 | S315 | 8,200 | 2.500 ; RM _ 68.38 | $860 | 2660 | 4.100 | 1250 Bunting 1192.5] 604 [457 | 3 [1.302 | 33.07 | 32000 | 1344 | 2000 | RMT 90.45 | 10750 | 4875 | 8000 | 2440 RM 68.38 | 5375 | 2440 | 4000 | 1.220 NR 60.28 | 3585 | 1625 | 2665 | 810 Grackle 1192.5] 604|sano] 3 [1.333 | 33.86 | 41900 | 1533 | 2281 | RMT 90.45 | 11,720 | $315 | 7650 | 2,330 L RM__68.38 | 5.860 | 2660 | 3825 | 1 165 Bittern i272 | essfas7 | 3 [4.345 | 34.16 | 34100 | 1434 | 2134 | RMT 90.45 | 10750 | 4875 | 7500 | 2285 RM 68.38 | 5375 | 2440 | 3750 | 1 145 NR 60.28 | 3585 | 1625 | 2500 160 Pheasant [1272 | 645 |5a/19| 3 {1.382 | 35.10 | 43600 | 1635 | 2433 | RMT 90.45 | 11720 | 531s | 7175 | 2185 | RM _68.38 | 5.860 | 2660 | 3585 | 1.095 Dipper 1351.5] 685 |45/7 | 3 |4.3e5 | 35.18 | 36200 | 1523 | 2266 |-RMT 90.45 | 10750 | 4875 | 7,060 | 2.150 RM 68.38 | 5375 | 2440 | 3.530 | 1075 NR 60.28 | 3585 | 1625 | 2355 720 Manin i3si.s}| oss |sano] 3 |x | 36.17 | 46300 | 1737 | 2585 | RMT 90.45 | 11,720 | $315 | 6755 | 2.060 [pm onrn_| s.x60 | 2.660 _| 3375 | 1.030 Bobolink [1431 | 725] 4577 | 3 [1.427 | 36.25 | 38300 | 1613 | 2400 | RMT 90.45 | 10750 | 4875 | 6665 | 2.030 RM 68.38 | 5375 | 2,440 | 3335 | 1,015 NR 60.28 | 3.585 | 1625 | 2220 | 675 Plover 1431 | 725 |san9] 3 [1.465 | 37.21 | 49 100 | 1.840 | 2738 | RMT 90.45 | 11,720 | 5315 | 6375 | 1,945 | RM 68.38 | 5.860 | 2660 | 3190 | 970 Nuthatch 1510.5 765 | 45/7 3 1.466 37.24 40 100 1 702 2533 RMT 90.45 10.750 4875 6,320 1.925 RM 68.38 | 5.375 | 2440 | 3160 | 965 NR 60.28 | 3.585 | 1625 | 2110 | 645 Parrot 1510.5| 765|s4n9| 3 | 1.505 | 38.23 | 51.700 | 1940 | 28090 | RMT 90.45 | 11.720] 5315 | 6.040 | 1.840 RM 68.38 | 5860 | 2660 | 3.020 | 920 Lapwing [1590 | 806 ]4s77 | 3 |1.508 | 38.15 | 42200 | 1792 | 2667 | RMT 90.45 | 10.750 | 4875 | 6,000 | 1.830 4 RM 68.38 | 5.375 | 2440 | 3,000 91s NR 60.28 |_3.585 | 1625 | 2.000 | 610 Falcon 1590 | s0o6|saio| 3 |a.s4s | 39.24 | 58500 | 2094 | 3042 | RMT 90.45 | 11720 | 5.315 | 5,740 | 1750 | RM 68.38 | 5.860 | 2560 | 2870 875 {— Chukar i780 | 902} 83/19] 4 [1.602 | 40.69 | si000 | 2075 | 3086 | RMT 9.60 | 19.080 | 8.655 | 9.200 | 2.805 Bluebird 2156 1092 | 84/19 4 1.762 44.75 60 300 PE 3737 RMT 96.60 18.830 8.540 7500 2.285 Kiwi 2167 | 1098]727 | 4 41.737 | 45.12 | 49800 | 2303 | 3427 | RMT 96.60 | 16.120 | 7.310 | 7.000 | 2.135 Thrasher 2312 1172 | 76/19 4 1.802 45.77 $6 700 2 526 3761 RMT 9.60 17,690 8.025 7,000 2.135 Joree 2515 1274 | 76/19 4 1.880, 47.75 6; 700 2 749 L 4091 RMT 96.60 17,325 7 860 6.300 1920 () Denote approximate value 54 IEEE OVERHEAD TRANSMISSION Li. JE CONDUCTORS Std 524-1980 Appendix F Drum or Reel Winding Stranded members should be wound on a finger protruding. Use the right hand for right drum or reel according to the lay and the lay and the left hand for left lay. The clenched direction of travel. fingers represent the barrel and the index finger Note the convenient thumb rule. Clench the the direction of pull-off. The thumb points to hand into a fist, but with the thumb and index the proper attachment site. Fig F1 Left Lay Right Lay Left Hand-Left Lay Right Hand-Right Lay Index Finger on Top Index Finger on Top Thumb on Right Thumb on Left Left Hand-Left Lay Right Hand-Right Lay es Index Finger on Bottom Index Finger on Bottom 2 Thumb on Left Thumb on Right 55 IEEE Std 524-1980 Wire rope L = (A+D) ABK (ft) Appendix G Drum or Reel Capacities oo. K = Constant as tabulated below and is ob- tained by dividing 0.2618 ft/in? by the oversize wire diameter squared* H Fiber rope L B(H* -D*) (tt) 15.2 d? § : ; d = rope diameter | | A, B, D, H and d are in inches B Fig G1 Table G1 Nominal Nominal Nominal Wire Diam In K, fuin?* Wire Diam . In K, fvin®* Wire Diam , In K. fuin?* 116 49.8 12 925 13/8 127 3/32 23.4 9/16 741 11R 107 V8 13.6 5/8 607 15/8 .0886 5/32 8.72 16 -506 13/4 .0770 3/16 6.14 3/4 428 17/8 .0675 7132 4.59 13/16 354 2 .0597 V4 3.29 718 308 218 0532 5/16 2.21 1 239 21/4 .0476 3/8 1.58 1 18 191 238 0419 76 119 1 ous 152 212 .0380 | *Values of K allow for normal oversize. Clearance shown on Fig G1 should be 2 inches unless fittings require greater clearance. The formula is based on uniform winding and will not give correct results if wound nonuniformly. It is based on the same number of wraps in each layer which is not strictly correct but which does not result in appreciable error unless the traverse of the reel is quite small compared with the flange diameter (H). 56 IEEE OVERHEAD TRANSMISSION LINE ( ONDUCTORS Std 524-1980 6 3 NOTE: CONDUCTORS TO ANCHORS (i) DELETED FOR CLARITY _ 1. Anchor (see 10.1.3) 9. Finger line 17. Reel stand A. Typical stringing arrangement 2. Running board 10. Pilot line 18. Crossing structure B. Typical pulling line installation with pilot line ~ 3. Bundled conductor 11. Pulling line 19. Snub structure (see 10.2) Cc Typisal installati f pulling li ith 4, Ground grid (see 5.5.5) 12. Confector link 20. Bullwheel tensioner a—_——_ with fate 5. Woven wire grip 13. $éivel link 21. Crawler tractor D. Typical installation of pilot lines with helicopter 6. Running ground 147 Bullwheel puller 22/ Traveler 7. Structure base ground 15. Drum puller 3. Pilot line winder 8. Traveler ground (see 10.2.3) 16. Ground rod 24. Ree] winder 1 & , 2 J , || wig 10 ‘ . Coinposite for the Installation of Overhead Transmission Line Conductors , 33