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AL~SK~ POWEP AUTHORITY
SUSITNA HYDROELECTRIC PROJECT
TASK 8 -TRANSMISSION
SUBTASK-8~02-PROGRESS REPORT
ELECiR I C SYSTEf~ STUDIES
·!>
MARCH 1981
ACRES AMERICAN INCORPORATED
1000 Liberty Bank Building
Main at Court
Buffalo., New York 14202
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ALASKA POWER AUTHORITY SUSITNA HYDROELECTRIC PROJECT
TASK 8 -TRANS.tvtiSSION
SUBTASK 8.02 -PROGRESS REPORT
ELECTRIC SYSTEM STUDIES
TABLE OF CONTENTS
f_age
LIST OF TABLES • • • • • • • • • • • • • • • • • • • .. • • • • • • • • • • • • • • • • • • • • • • • . • • • • • • • • • • • • • i i ; ,., ..
• • • • • • c • • • • • • • • • • • • • • • ~ • • • 0 • • • • • • • • • • • • • • • • ~ • • • • • • • • • • • • LIST OF FIGURES
1 -INTRODUCTION •••••••••••••••• ·• ••••••••••• & •• ~ •••••• 0 ••••••••••••••.••.•
1 .. 1 -Background ................................................... .
1. 2 ·-Repo.rt Contertts ........................... ~ ......•............
1-1
1-1
1-1
2-S.UMMARY .................................................. ,. .... ;~ ....•. 2-1
2 .. 1 -Scope of Work .................................................. ·2-1
2 .. 2 -Reports Reviewed ..•.............. 8. • • • • • • • • • • • • • • • • • • • • • • • • • • 2-1
2.3-Planning Criteria ........................ ·, ..................... 2-1
3 -APPROACH ......... ,. .....••...•........ ·.. . . . . . . .. . . . . . . . . .. . . . . . . • . .. . . . . 3-1
4 -DESCRIPTION OF STUDIES AND PRELI~UNARY RESULTS ...................... 4-l
4.1 -System Data Assembly ...................•.•................... 4-1
4:2 -System Load Distribution •...•.•....•..•.......••............. 4-1
4.3 -Description of Studies ................................ o ••••••• 4-1
4.4 -Preliminary Results of Studies ............................... 4-3
5 -GENERf.\L COMMENTS •••• · • • • • • • • • • • • • • • . • • • • • • • • • • • • • . • • • • • • • • • • .. • • • • • • • 5-1
APPENDIX A -PROPOSED PLANNING CRITERIA
B -TRANSMISSION LINE -ECONOMIC CONDUCTOR SIZE
ATTACHMENT -LETTER TO APA, DATED MARCH 24, ~:981
SUBJECT: TRANSMISSION LINE CHARACTERISTICS
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LIST OF TABLES ·
Number
4.1
4.2
4 .. 3
Title Page
Staging of the Susitna Development •..•....•...•.•••.......... 4-5
Maximum Power to be Transmitted to Anchorage
and Fairbanks For Each Stage of Susitna Development ........... 4-5
Line Losses· Under Maximum Power Transmission ................. 4-6
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LIST OF FIGURES
Number Title
4.1 345 kV System···············"·············--·············· ... ···· 4-7
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1 -INTRODUCTION
1.1 .... Background
The Plan of Study {POS) for the Susitna-Hydroelectric Project, which is current-
ly being undertaken for the Alaska Power Authority by Acres American Inc.
includes studies of the required transmission system under Task 8.
Subtask 8.02 of Task 8 is entitled Electric System Studies. The objective of
this subtask, as defined in the February 1980 POS is as follows:
uro ensure that the electrical aspects of the project design are integra-
ted with the existing Railbe,lt area power systems and to design an elec-
trical power system which is reliable and economic ...
The Transmission System for the Susitna Project, as currently envisaged, will
ultimately involve 1 ines from the 1Jatana and Devil Canyon sites to both
Fairbanks and Anchorage. The system will also be compatible \'lith ·the proposed
intertie between Healy and Fairbanks which is presently under study for the
A1 aska Power Authority by Commonwealth Associates. ·
\~ork on Subtask 8.02 commenced in June 1980 .and is scheduled to be complete by
March 5, 1982. The purpose of this progress report is to present the resu1ts of
work c_ompleted under Subtask 8.02 through February 15, 1981-.
1.2 Report Contents
A summary of the report is presented in Section 2 and the approach adopted in
the studies in Section 3. A description of studies undertaken and a discussion
of pre11min~~.Y results follows, in Section 4. Gene·ral comments on the results to
date are presented in Section 5.
Appendices A and B and an attachment are also included ~s support documents
which have been issued to advise APA of early study findings. ·
1-1
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I 2 -SUMMARY
•. 2.1 -Scope of Work
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The scope of work includes the following:
planning criteria
-system data. assembly
-power delivery points
-line loading
·preliminary system configurations
-preliminary cost for alternatives
-preliminary screening of systems
-recommend transmission configuration, voltage, and conductor size.
2.2 -Reports Reviewed
The following reports were reviewed as to content relating to the scope of
work.
..
-U.S. Corps of Engineers/Alaska Power Administration -Susitna Hydroelectric
Project Interim Feasibility Report .. Sect ion H -Transmission System,
December 1975.
-International Engineering Co, Inc/Robert H. Retherford Associates Economic
-Feasibility Study Report, December 1979.
-Institute of Social and Economic Research -Electric Power Consumption for
the Railbelt: A Projection of Requirements, May 1980.
,.
-Woodward -Clyde Consultants: Forecasting Peak Electrical Demand For
Alaska's Railbelt! draft September, 1980 and final report December, 1980 -
Subtask 1.02o
-Subtask 1.01 -Closeout Report, Review of ISER Work December, 1980.
-Corrmonwealth Associates Inc -Anchorage -Fairbanks Transmission Intertie
draft November, 1980.
-Commonwealth Associates Inc -Anchorage -Fairh ... nks Interconnection
Fe as ib il ity Study, January, 1981.
-Subtask 6.36, Generation Planning-Preliminary Information.
2.3 -flanrling Criteria
System planning criter·ia (Appendix A) \'/ere submitted to APA in ·August, 1980.
The system study assumes a fully developed Susitna potential so that final
system parameters can be determined. The criteria are based on the desirability
to maintain· rated power flow to Anchorage and Fairbanks during the outage of any
single 1 ine or transformer element. The essential features of the criteria. are
as follows~
2-1
. . ~ . . . · : . . .
t. ~ " ... . • !'. • • •
-total power output of Susitna to be delivered to two stations at Anchorage
and one at Fairbanks
-"breaker-and-a-half11 switch~ng station arrangements
-dynamic overvoltages during line ener·gizing not to exceed specified limits
-system ~oltages to be within established limits during normal operation
-power delivered to the loads to be maintained and system voltages to be
kept within establi~hed limits for system operation under emergency
conditions
-transient stability during a 3-phase line fault cleared by breaker action
with no reclosing
-where performance limits are exceeded, the most cost effective corrective
measures are to be taken.
2-2
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3 -APPROACH
The following steps were adopted and pursued to achieve the preliminary subtask objectives.
-develop system planning criteria (paragraph 2~3)
-ass.emb1e existing system data (obtained by RWRA)
-study present load distributicn to Anchorage and Fairbanks
-establish bulk power delivery points
-obtain development capabilities (from Task 6)
·-determine 1 inE! loadings at each development stage
-examine various system configurations
-compare various systems on a performance and cost basis
-make prelimin~ry voltage recom~endation
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4 -DESCRIPTION OF STUDIES AND PRELIMINARY RESULTS
4.1 -System Data Assembly
The services of R. W. Retherford· Associates were obtained August, 1980 to
gathet .. system data from the utilitieso The final data assembly was completed
late October, 1980.
4.2 -System Load Di stri buti on
Based on the ISER load forecasts (low~ medi urn and high load growth), the
di strihutron .of the total Rai lbelt load between Anchorage and Fairbanks ar'eas
remains essentially constant throughout the range of load growth p·r-edictions.
Anchorage is predicted to have approximately 80 percent of the total load
with Fairbanks having the r-emaining 20 percent. To allow for some variations
in the forecasted load split, the transmission system will be designed to
deliver 85 percent of total Susitna power to Anchorage and 25 percent to
Fairbanks. ·
The foregoing was studied after receipt of system data and the delivery
points, two at Anchorage and one at Fairbanks were estab 1 i shed in November,
1980.
4.3 -Description of Studies
(a) Power Transfer -After studying various reports 1 i sted above and
obtaining preliminary information on the staging of Susitna from Subtask
6.36, Generation Planning, the electric system studies were able td proceed
in December, 1980o Table 4.1 shows the staging schedule for the Susitna
Development. The maximum power to be transmitted to Anchorage and
Fairbanks for each stage of development, based on the 85 percent and 25
percent limits is given in Table 4.2. The load power factor is assumed to
be 0.95 and the power factor capability of the Susi tna generators is
assumed to be 0.90.
Following determination of the system power transfer requirements for each
stage of Susi tna deve 1 opment, alternative system configurations were
developed taking into account the following:
-initial Susitna development at the Watana site
-a major switching station at Devil Canyon or near Gold Creek
-possible intermediate switching at Willow and Healy.
Preliminary line lengths for the system configurations under study were
obtained from Subtask 8.03, Transmission Line Rout~: Selection ..
Having established the peak power to be delivered and the distances over
which it is to be transmitted, transmission voltages and number of circuits
required were determined. To maintain a consistency with standard ANSI
voltages used in other parts of the U.S.A., the following voltages were
considered for Susitna tran$mission.
4-1
(b)
(c)
-Watana to Devil Canyon or
Gold Creek and on to
Anchorage
-Devil Canyon or Gold Creek
to Fairbanks ..
500 kV or 345 kV
345 kV or 230 kV
(,)
Conductor Sizes -Based on the selected transmission and power transfer
requ1rements at the var·ious stages of Susitna development, economic
cnnductor sizes can be selected. The methodology used to obtain the
economic conductor size and the results obtained are outlined in Appendix
B, 11 Transmission Line-Economic Conductor Size11
• Also included in
Appendix B are the capit~~lized costs of transmission line losses. The cost
of these losses are taken into account in comparing the overall costs of
alternative transmission schemes.
When determi ni ng1 appropriate conductor size, th\ · se 1 ected conductor i s
checked for radio interference (RI) and corona "equirements. If RI and
corona performance are within acceptable limits~ then the selected
conductor based on economic analysis may be used4 On the other hand, where
necessary to satisfy RI and corona performance requirements, a larger
conductor size may be selected.
Total line lassos for the proposed conductor size for each of the different
line voltages be·ing considered are given in Table 4.3. These losses are
for the alternat·!ves where a major switching station is located at Devi 1
Canyon. The losses given are the total losses for transmis;;ion from Devil
Canyon to Anchorage and from De vi 1 Ca;tyon to Fairbanks. The line ·from
Devi 1 Canyon to Anchorage is 155 miles long.. The losses were calculated
for the maximum expected power transfer to Anchorage and to Fairbanks for
each of the stages of Susitna development as given in Table 4.,2~
Line Energizing and Outage Coaditions -Following selection of the
conductor sizes using economic, RI and corona criteria, computer
simulations of line energizing were carried out. These simulations w ·."e
performed to determine shunt reactor requi.rements necessary to ensure that
dynamic overvoltages during line energizing. remained below the values
established in the system planning criteria .. (See attached Appendix A).
Once the line reactor requirements were established, computer load flow
simulations of single contingency outage conditions were commenced. The
purpose of these simulations is-to determine the following:
-need for intermediate switching stations
-transformer tap settings
-need for, and magnitude of series compensation
-var generation requirements at the load centers
These simulations are being carried out for the various transmission system
configurations and stages of development of Susitna being considered and
are current 1 y in progress.
4-2
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(d) Pre 1 iminary Cap ita 1 Cost Estimates -These estimates wi 11 be engineering
type estimates with an appropriate cent ingency to cover any unforeseen
construction problems.
In working up the transmission 1 ine costs, Acres referred to RWRA
experience in Alaska_. The line costs are based on an X-type tower. The
cost figures developed are consistent with CAI January, 1981 transmission
1 ine costs.
Appendix B shows the methodology of obtaining the line costs as a function
of voltage and conductor size. The capitalized cost of 1 ine losses are
_also treated in this appendix.
Substation equipment costs were developed, based on unit costs in the U.S.
Department of Energy, Federal Energy Regulatory Commision publication,
11Hydroelectric Power Evaluation 11
, August 1979 edition. The costs obtained
from this publication were escalated to reflect 1981 levels and the higher
cost of 1 abor in Alaska.
4.4 -Preliminary Results of Studies
·The studies performed to date (February 15, 1981) have given preliminary
results as.follows:
(a)
(b)
(c)
(d)
(e)
(f)
345 kV is a viable voltage for transmission from Susitna to Anchorage and
to Fairbanks and appears to be the economic choice.
Two circuits are expected to be adequate to each 1 oad center~ however., the
circuits to Anchorage will require series compensation to handle the
heavier loading to the south. System configuration is shown in Figure 4.1.
Conductor sites (preliminary) are 2 x 1272 MCM to Anchorage and
2 x 795 MCM to Fairbanks.
Costs and performance calculations to date are inconclusive as to the
preferred location of the Susitna terminal station -either Gold Creek or
Devil Canyon. Final decision may be based on other factors.
Intermediate switching at Wi 11 ow is a cost-effective ~tJay of improving the
contingency performance of transmission· to Anchorage. It also has the
advantage of facilitating the supply of future load at this point (e.g.
future capital) ..
Studies are based on two delivery points in the Anchorage area to handle
the u 1 t imate 1 oad i n!:~O'f 1020 to 1190 MW. [This is based on assumed
requirements for subtransmission rights of way in the load area and has no
impact on the question of primary transmission voltage and configuration].
(g) Transmission to Fairbanks does not need an intermediate switching station
at Healy to satisfy contingency requirements. This could be added if
required for load or generation at this point.
4-3
The cost estimates obtained from these studies were used to calculate
transmission system costs for the "1981 Upper Limit Capital Cost Estimate and
Associated Economic Analysesu dated March. 1981.
4-4
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TABLE 4.1 -STAGING OF THE SUSITNA DEVELOPMENT
Year -
Watans
Increments
Susitna C~acity -MW Devil anyon
Total Increments Total
Susltna
Total
199J
1996
2000
400
400
2000 (optiona.) -
400
800
400
200
400
600
400
800
1,200
1,400
TABLE 4.2 -MAXIMUM POWER TO 8~ TRANSMITTED TO ANCHORAGE
AND FAIRBANKS FOR EACH STAG£ OF SUSITNA DEVELOPMENT
Total Susitna Maximum Power Transmission
C!Eaeit:t (MW) To AnChorage (MW) To fairbankS (MW)
400 340 100
800 680 200
1,200 1,020 300
1,400 1 '190 350
Note: For system planning purposes a mriximllll of 85 percent .of. Susitna
generation is assumed to be transmitted to Anchorage and a maximum
of 25 percent to Fairbanks.
4-5
0
TABLE 4.3: LINE LOSSES UNDER MAXIMUM POWER TRANSMISSION
Susitna
Capacity (MW)
400
800
1,200
Susitna
Capacity (HW)
400
800
1,200
1,400
Devil Canyon to Anchorage (155 miles)
Pnwer · 5otrkV 345 kV . 3 circuits
Transaitted (MW) 2 Circuits (MW) 2 Circuits (MW) (MW)
340
680
1,020
1,190
1.5
.6.2
13.8
18.8
3 .. 2
12.8
28.8
39.2
2.9
11.2
.25.5
35.3
Power . · 345 kv · DO kV
Tranmwitted (MW) 2 Circuits (MW) Z Circuits (MW)
100
200
300
350
4-6
0.5
2.0
4.6
6.3
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ANCUOUAG& It ifAIRBANKS
WILLOW
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E 65 ~I SO MI 189 MI
138 K
345 KV 15 MI
138 K.V
·-:( 65 MI
90 MI 189 i-ii
345 Kv·
345 KV
ANCHORAGE I
LEGEND
345 KV DEVIL CANYON -LOAD e--GE~lERATION
&-VAR GENERAl'ION
~E-.SERIES C~iPENSATlON
27 Mt
..-rvY"\._ SUUNT UEACTOR 27 MI
~ GENERATOR TRANSFORMER(S)
~ STEPDOWN TRANSFOnMER(S) 345 KV WATANA
WITH TERTIARY WINDING
345 KV SYSTEM FIGURE 4.1 filii
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·s-GENERAL COMMENTS
Transmission planning studies are still in progress examining the impact of
conti ng~n<;Y~.o~;t,~aes and transi e1 .~t · stability on system configuration. Other
detai Ts ___ wfi1ch are not yet fi na h zed and which may influence the transmission
configuration are the sizes and staging of generation at Watana and Devi 1 Canyon
sites.
Current work on transient stabi 1ity has shown that survival of a three-phase
fault on the EHV system will be difficult (and costly) to achieve~ The
arbitrary choice.of a three-phase design fault in the planning criteria may
have been undu1y severe,. since multiphase faults are rare in EHV systems •
. Further study is needed but we may propose changing to EHV design fault in
-the planning criteria from "three-phaseu to "sing1e~line-to-ground 11 •
Structural and mechanical detai 1 s of the trqnsmi ssi on system have not been
studied as yet. These will be addressed after completion of the electrical
system· studies.
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APPENDIX A
P"ROPOSED PLANNING CRITERIA
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SUSI~'NA TRANSMISSION PLANNING
PROPOSED PLAi~NING CRITERIA
July 22, 1980
P5700.08
I'n general, we propose to plan transmission facilities so
~"lat single contingency outages will not result in restrictions
in power transfer although voltages may be temporarily out-
side of normal limits. The proposed guidelines concerning
stability, system performance limits and thermal overloads
are detailed below.
{a) Stability
The system \\Till be checked at each stage of development
for transient stability. In the case of multiphase
faults, delayed reclosing is assumed, \vhereas high
speed rcclosing would be attempted following single-.
ph;,:;~" faults that ~vere cleared by single pole switching.
-.
The de:>i9n fault for transienc stability check would
!;C' ~ 1-phnsc fault cleared in ~ cycles by the local
h:•'}~: .... r nnd 8 cycles bythe r~~mote breaker, vlith no
.,.. -..... 1 r:·~ l. n·""" ... t "\.~ .... . " : •
(Note: l\t later· sta .. ;es of de~;ign it may be useful to
check dynamic stability for unsuccessful
rcclosurc of a SLG fault cleared eventually
by 3-phasc trip and lock-out following initial
single-pole trip. For the present, a 3-phase
design fault is considered to be equivalent
in terms of severity.)
(b) Station Configuration~
The determination of system transmission requitemerits
\vill be based (initially at least} on assumed. success-
ful breaker operations. When the oaf feet of a stuck
breaker is examined, the clearing of back-up breakers
will be based on 11 breaker-and-a-half11 ::.;witching
arrangements.
{c) System Energizing
Line energizing initially and as part of routine
switching operations will generate some dynamic over-
voltages. System design should be arranged to keep
these.overvoltages within the following limits
-line open-end voltages at the c-remate end should not
exceed 1.15 pu on line energizing
-following line energizing, switching of transformers
and VAR control devices at the receiving end should
bring the voltage down to 1.10 pu or lqwer
.
-the step-change in voltage at the energizing end
of the line should not exceed 5 percent.
(d) Load Flow
System load flows will be checked at each .stage of
development to ensure that the system configuration and component ratings ,are adequate for normal and
emergency operating conditions. The load levels to be
checked will include peak load, minimum load (assumed
50 percent of peak) and also any intermediate load
level tht3.t is judged to be critical due to off-peak
sh:.! t do\.;n of loo.d-ccnter generation.
2
Nor:nal system flows must be v: i t:.hin all normal thermal
li:-:-its for transformers and l~acs, nnd should give bus
'.tolt.vr(!S on the _EHV system tvit..hin +5 percent, -10 percent,
~nd t1t subtran!.;mi~sion buses within +5 percent, -5 percent~
" ~ Em~rgcncy system flo·.-.rs with the loss of one system
ele:ncnt must be within emerge:1cy thermal limits for lines
and transformers (20 percent 0/L). Bus vo;t.tages on
the EHV system should be v1ithin +5 percent, -10 percent,
and at. subtransmission buses \..rithin +5 percent,.
-10 percent.
(e) Corrective Measures
Where limiting performance criteria are exceeded,
system design modifications will be applied that are
considered to be most cost-effective. Where conditions
of low voltage are encountered 1 for exampler power
factor improvement would be tried. 1ihere voltage
variations exceed the range of normal corrective
transformer tap change, supplementary VAR generation
and control would be applied" Where circuit and
transformer thermal limits are about to be exceeded,
additional elements·would be scheduled.
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(f) Power Delivery Points ·
For study purposes, it will be assumed that when
Susitna generation is ·fully developed (i .. e .. , to
approximately 1,500 MW), the total output will be
delivered to 'terminal stations as follows
-Fairbanks -one station at Gold Hill .
Anchorage t"t--.70 stations
-one c.-'c Palmer
-one 11 elsewhere 11
-(the two stations at Anchorage would be
interconnected at EHV.)
The provision of intermediate switching stations along
the routc.·may prove to be economic and essential for
stability and operating flexibility. Utilization of
thr·::~· ~·..;i r-ching stations for the supply of local load
·..;ill b .. ! ~xamined, but security of supply to Anchorage
~nd Fairbank~ will be given priority consideration.
MWS:rf
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M. W.
L ..,= • ( 1 ft..' I ./ r-v··r-v Cl. ~-A-
Stoc.ldart
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APPENDIX B
TR..l\NSMISSION LINE
ECONOMIC CONDUCTOR SIZE
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TRANSMISSION LINE -
ECONOMIC CONDUCTOR SIZE
1 -INTRODUCTION
February 13, 1981
In EHV tra.nsmis=-ion, line conductors and conductor bundles
must be sized to minimize corona, RI and audible noise
effects. An additional factor that needs to be quantified
is the economic incentive to increase the conductor section
still further to achieve savings in the future cost of line
loss.
This appendix deals with the economic aspects of conductor
sizing, and since both line costs and line losses ar~ pro-
portional to line length, the analysis is carried out on the
basis of costs per circuit -mile.
2 -LINE CAPITAL COST
Transmission costs are generally a function of the trans-
mission voltage and conductor size, modified by local
considerations such as me~eorological factors, access,
transport costs and local labor costs. At a particular
voltage, the variation in line cost as a function of conductor
area is normally of the form
On the basis of line·cost estimates for Alaska, values of
"Kl", nK2u and "a" have been determined. These are
approximate, but they describe the relationship between
line cost and conductor size sufficiently well to be used
2
as a guide in dete·rrnining the economic size of line conductor ..
The equations are shown belew
230 kV = $/mi...te ~ 125,000+2 ( 1\l C M ) 1 • 4 5
345 1<. v = $/mi_i_e ~ 175,000+2 {MCM)1.45
500 k.V = $im-i...te.. ~ 300,000+2 ( M C 1\l ) 7 • 4 5 .
3 -CAPITALIZED COST OF LOSS
Line loss varies directly as the square of the line loading
and inversely as the conductor cross. sectional area. Since
the line loading varies in a daily pattern and also through-
out the life of the facility, these variations must be
taksn into account.
Daily variations in load are described by the Load Factor
(LF) which in the railbelt area is expected to be about
62 .. 5 percent.. The average annual energy capability at
Susitna is also of the same order, and the load factor of
line losses (LLF) is estimated to be
LLF = (LFJ 2 +LF
2
= {0.625) 2 +0.625
2
= 0.508
LLF ~ 0.50 ..
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3
Transmission line loading over the life of the facility
can orily be estin:tated at this time. According to generation
planning studies, each time a block of 400 MW of generation
is cotn.T'!lissioned (in years 1993, 1997 and 2000), this
capapility is fully absorbed by the system. Generation
additions after year 2000 cannot be forecast with any.
certainty. The contribution to loss energy from any
additional peaking capacity would be negligible, hence, the
following load pattern kS assumed.
Period
1993 -1996.
1996 -2000
2000 -20 43
Susitna
Caoacity
(HW)
400
800
l 200
~ine Loadings -
To
Anchorage
320
640
960
{MW}
To
Fairbanks
80
160
240
Expressing line loading and line resistance in per unit on ·
Surge Impedance Loading (SIL} and surge impedance {Ze)
base leads to the following expressions
Li.n:e -'l.e.~.s .i...~!> .tan c. e.
I n £..{. n e. i o a. d.i. n g
100 ohm.~~ peJt m.i.ic. -· XlTIT
100 1 pe-t LUt.i...t pe.t = .\fC,'.l X. Ze
= S pe4 unlt on SIL ba~c
-S 2 X TOO X J pe~ anlt MC~\I TC:
k. v 2
= z-e '~'-'Htl 1
m L l.c
2 100 1 kv 2
= S x ITC"i\f x. z c. x. Tr ( Af W I m ,{. e. e. }
S 2 100 lzV 2
= X ~ X -
1
.2 X 8. 76 X LLF
c.
{ GW • It I m f.. t \.?..}
4
And i6 the eo6~ o6 loJ~ ene.~gy = e ~/kW·h
= c. $ M.<.t.e..i. o n I Gltf • It
2 1 0 0 . lc V 2
= S x x ---rr x. 8~76 x. LLF x. e ~ -9 {. Ze
{ $ AU. t tl o n I m .[ e. e. )
Typical values of LLF and C for Susitna are
LLF = 0.50 (a~ deve~oped ea~lle~)
. .
c. = ~ 0·. 0 3 5/ltW • h (an ave..tag e. 6ig u.~e. de.ft...L v e.d in the 0 GP-5
pl.annlng -~.tu.dle .. ~ ba,s e.d on. Z(Uto J..n6ta.tLon
and 3 pelteen-t ne..t eo.~t o& money)
A () t , f) _ 75.33 s 2 ~tv 2 ($ .11 -o"· 1 ·p} naua..(.. c. a .6 ~ o 0 .{..o .. ) ... s -. 1 •• .{ {.. E.t on m.<... t.e .
MCAI Z c. ...
In tables 1 and 2 the capitalized cost of loss per mile is
derived for transmission to Anchorage and Fairbanks 1
respectively,as a function of conductor size and for the
line voltages that are being considered.
In Table 3 the 1?-ne capital cost and capitalized cost of loss
are shown for ea!~h voltage and transmission route. Also
shown are the optimum conductor sizes based on loss
evaluation. The relationship between total cost and
conductor size is sho\.vn graphically in Figure 1 for trans-
mission to Fairbanks and Anchora<:e. Line loadings at 50 0 I~ V
to Anchorage and at 345 kV to Fairbanks are low and lead
to conductor sizes below the acceptable limit from an RI and
Corona point of vie~T. Pr9posed conductor sizes for the
various line sections, taking into account Corona arid RI
effects, are shown at the bottom of Table 3.
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TABLE 1
TRANSMISSION LINE TO ANCHORAGE
DEVELOPMENT OF CAPITALIZED COST OF LOSS
Loading Perl
Annual3 Fac or4
Circuit 1 1 1 Capitalized
Total on SIL Cost of Duration of Offset from X Cost of·
Period Load Base2 Loss Load Period P.W. Datum T (l+i)m Loss
{MW) Un·l) (S-pul. ($M/MCM) (n-Y:ears) (m-years) ($M)acM) "'
1993 -1996 320 160 0.386 3 .. 305 3 0 2. 8286 9;.3-•9
1996 -2000 640 320 ~ 0.771 13.186 4 3 3.4017 44 .. 855
• ltl
.2000 -2043 960 480
<ql
rt'l 1.157 29.695 43 7 19.4995 579;.,037
Total at:. 345 k.V = $M 633~241/HCM
1993 -1996 320 160 0.178 1~5737 3 0 2.8286 4 .... 451
1996 -2000 640 320 ~ 0.356 6.2949 4 3 3.4017 21 .. 41.3
0
2000
0 0.533 14.1105 43 7 19,4995 275 .. 1.47 -2043 960 480 ltl
Total at 500 kV = $M 30l.Oll/MCM
"
1 T . . 't d
2 wo c1rcu1 s are assume •
SIL base values are: 415 MW (345 kV) and 900 MW (500 kV).
3Annua1 cost of loss = 15.33 s2 kv2Jzc2, based on losses valued at $0.035/kW•h and a 50 percent loss load factor.
4present worth discounting is at annual rate of 3 percent.
TABLE 2
TRANSMISSION LINE TO FAIRBANKS
DEVELOPMENT OF CAPITALIZED COST OF LOSS ..
Loading Perl
Factor4
circuit Annuall 1[1 _ 1 xL
cap:it:alized
Total on SIL cost of Duration of Offset from
cost o:f
Period Load • Base2 Loss Load Period p .• w. Datum I (l+i)n (l+i)m LOSS
(MW) (Mrl) (S-pul T$M/MCM) In-years) (m-years)
(.$M,IRCM.)
1.993 -1996 80 40 0 .. 292 0.4665 3 0 2.8286 1 .. 31.95
1996-2000 160 80 0.584 ~I 1.,8660 4 3 3.4017 Ei .. l416
2000 -2043 240 120 o. 87.6 ~ 4.1984 A~ 1 19.4995
Sl .. S-10
---
...
Total at 230 kV • $M 0$ ... S331/MCM
1993 -1996 80 40 0 .• 10 ~I 0.2061 3 0 2.8266 0: .. 5~30
1996 -2000 160 80 0.20 o. 8243 4 3 3.4017 -t .. a:2uo
2000 -2043 240 120 0.30 1. 85·41 43 1 19.4995
3.6· .. l.t'60
Total at 34S ltV ., $M 4Ch.~lil 7/MCM
1 TWo circuits a£e assumed. 2siL base values are: 137 MW {230 kV) and 400 MW (345 kV). lAnnual cost of loss = 15.33 s2 kVlJzc2, based on losses valued at $0.035/kW•b and a 50 percent loss load factor.
4present worth discounting is at annual rate of 3 percent.
(J
_____ ! ___ _ ,.
TABLE 3
SU!-1MARY OF ECONOMIC FACTORS AND
PROPOSEO CONDUCTOR SIZES
Voltage
Transmission to Anchorage soo kv 345 kV
Capital cost of line
($M/mile)
Capitali;edl cost of loss
($M/~'ile)
Optinnun conductor s i~
(i<!Cl.f)
Proposed conductors
0.30 + ~ (MCM)1 •45
10
301.011
MCM
1
(
'301 .• 9llxl06 \ 2 .. 45
2.9 . 1
= 1:,870 MCM2
3x795 MCM
0.175 + b-(MCM)l.-4S
10
633.241
f.!CM
1
(
633.24lxlo6 )2 •45
2.9
= 2,533 MCM
2xl,272 MCM
Transmission to Fairbanks
34S kV 230 kv
0.175 + 2 (MCM)1 •45
to6
40.975
MCM
89 .. 534
MC.t-t
l. 1
{40. 97Sxlo6 Y2 • 45
\2.9 1 (89.534x!o6)' .'1:~45 ·
~ ·g : ..... .
= 829 MCM 2
2x795 MCM
= 1,140 MCM
lxl,272 MCM
1 capitalized cost of loss expressions are derived in tables 1 and 2.
2The economic conductor areas for 500 kV to Anchorage and 345 kV to Fairbanks ,are smaller than the minimum needed fol:' RI
and Corona performance. Hence, RI considerations vill dictate conductor si~~e ..
0.4
.
"'-.
"-TOTAL COST INCLUDING ---,.,., CAPITALIZED LOSS ---~ ........ '54~'1.....--230 KV --._..--
0.3 -(/) z
0 -_.J
..... .__ ~ .,. ...
-----------·~-........... ~
...J -:E
-
UJ 0.2
....J -:a
___ .....
~----
--.,.,. ......... -----~ --.,.,-'3451<.~--...... -----~
a::
L&J
0.
L LINE CAPITAL COST
z~ov.:v~ ----
...
fJ)
0
(.)
-
0. I
0
500 1000
CONDUCTO·R AREA { MCM)
{TOTAL)
TRANSMISSION TO FAIRBANKS
1500
FIGURE lA
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-(J) z
0
:::i
0~7~----------~----------~----------~--------~
TOTAL COST INCUJOtG
CAPITALIZED LOSS
::! 0.5 t-------+-------+------+---------1 :s -UJ
...J -~
cr
1.&.1 a..
...... 0.4
.(I)
0
(.)
~.,._LINE CAPITOL
COST· 345 KV
,
--~ 0.2 .... _____ ......_ _____________________ ..__ ,. -·-· -· -~---·--
1500-2000 2500 3000 3500
' TOTAl CONDUCTOR AREA (MCM)
TRANSMISSION TO ANCHORAGE
FlGURElB ~~~~
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ATTACtr!YlENT
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Narch 24, 1981
P5700.11
T.783
r~r. Eric P. Yould
Executive Director
Alaska Po~tJer Authority
333 West 4th Avenue
·Suite 31
Anchorage$ Alaska 99501
Attention: Mr. David Wozniak
Dear Dave: Susitna Hydroelectric Project
Transmission Line Char3cteristics ;__; ___ -.w .... .. --·
t~e are attaching one copy of interoffice memo from t1. H. S~oddart/
I. R. Shepanik to E. N. ~hudeed. This memo or1tlines t~a: tr.Jnst:lission
line characteristics required 1:hich \vil1 carry the pro_:,-.cted 1400 ITI\'1
Susitna capacity to Anchor<.1ge ond Fai rban~:s ~
This information was previously given to A.-Poppens of C;1! ,-.i f.·~;r·uary 20,
1981 ..
As noted in the memo, the typE:·~ of com:fuc tor used in thf: •, ~ .;-·:
but the conductor capacity is tonsidered as a mini~um. I: t·~
proceeds with 345 kv construction, any conductor choirn ,: :!
coordinated with the Susitna ~ quirements.
ENS/ljr
-Attachment
cc: A. D. Poppens
ACRES AMERICAN INCORPORATED
Con:.c!tt~g Eng r:-oers
The Lib~rty aar.~ e• .... :cmg, :.~1\>n nt c"-wt
Buffalo ::~::·.•.· Yor:-: 1.!.202
-[John ~. lawl"ence r;r· Project Manager
\1 rf! typi ca 1 .. .. ,_ . 1r.~.-er~..1e
... ~ ~losely
TO:
FROM:
SUBJECT.:
OFFICI: MEMORANDUf\.'1
E. N. Shadeed Date: March s, 1981
File: P5700.07.08
M. w. Stoddart
I. R. Shepanik cc:
SUSITNA TRANSMISSION LINES
We -are currently carrying out electric system studies to
determine transmis~ion requirements for the Susitna
. development. The \vork performed to date indicates that
the recommended characteristics for the lines from
Susitna to !1.nchorage· and Susitna to Fairbanks will be as
follO\-lS •
Voltage
Number -c;rcuits 0!:
Number of conductors pt'r bundle .
Conductor size
Conductor type
Susitna to
Anchor a<i~-
345 kV
2 z·
1272 J.~c ... ~ ,, ,_
Pl1~.:l r-:"1•1 t ... • .. -...>c.. l.
Susitna to
Fairbanks
345 kV
2 ... ...
7'15 r·1CH
'" '... d • t \ tar
The conductor size for the line fro::t Sus i tna t.~J :.;1chorage
\Jlas chosen for econor:1i t" reasons. For th-:; Sur: i t: .. 1 to
Fairbanks line the conr!uctor size wns r;c lect.c ! ~ o !': c1 tisfy
radio in terferencc and corona require~··:; t r;, ~ .. ,· .. ·h in this
case override econon~ic considerations.
The tower-line dimensions on which calculations of radio
{! • interference and corona performance were based are gl.ven
belo'tv. Similar dimensions were used for both the lines
from Susitna to Anchorage and those from Susitna. to
Fairbanks.
tower height -95 ft
-conductor height above grou:q.d -85 ft at tower
-30 ft midspan
horizontal phase spacing -27 ft
-bundle spacing -18 in.
Our studies related to conductor selection focussed on
conductor cross sectional area and conductor diameter.
These indicated approximately 2x1272 HCM for circuits to
Anchorage and 2x795 HCM for the circuits to ~airbanks.
\men the total line design is being optimized there will
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E. N. Shadeed March 5, 1981
be some trade-offs ,bettveen tower cost and conductor cost,
and these will lead to the selection of conductor tvoes -.. with stranding and strength characteristics that are part
of an optimized design. The conductor types used in our
calculations, Pheasant and Mallard, are considered typical
but not necessarily the final choice.
Any s;gnificant departures from the above that are being
considered for a 345-kV intertie should be chec}~ed for
compatability with future Susitna requirements.