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HomeMy WebLinkAboutUtility Test Results of a 2 Megawatt 10 Second Reserve Power System 1999 SANDIA REPORT SAND99-2570 imi Release andia National Laboratories Albuquerque, Ne exico 87185 and Livermore, California 94550 Sandia is a laboratory operated by Sandia Corporation, omp ny, for the United States Department of ct DE-AC04-94AL85000. "public release; further dissemination unlimited. ih Sandia National Laboratories Issued by Sandia National Laboratories, operated for the United States Department of Energy by Sandia Corporation. NOTICE: This report was prepared as an account of work sponsored by an agency of the United States Government. 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This report has been reproduced directly from the best available copy. Available to DOE and DOE contractors from Office of Scientific and Technical Information P.O. Box 62 Oak Ridge, TN 37831 Prices available from (703) 605-6000 Web site: http://www.ntis.gov/ordering.htm Available to the public from National Technical Information Service US. Department of Commerce 5285 Port Royal Rd Springfield, VA 22161 NTIS price codes Printed copy: A05 Microfiche copy: A01 SAND99-2570 Unlimited Release Printed October 1999 Utility Test Results of a 2-Megawatt, 10-Second Reserve-Power System Benjamin L. Norris 121 Starlight Place Gridwise Engineering Company Danville, California 94526 Greg J. Ball Energy and Environmental Economics, Inc. 353 Sacramento St., Suite 1540 San Francisco, California 94111 Abstract This report documents the 1996 evaluation by Pacific Gas and Electric Company of an advanced reserve-power system capable of supporting 2 MW of load for 10 seconds. The system, developed under a DOE Cooperative Agreement with AC Battery Corporation of East Troy, Wisconsin, con- tains battery storage that enables industrial facilities to “ride through” momentary outages. The evaluation consisted of tests of system performance using a wide variety of load types and operat- ing conditions. The tests, which included simulated utility outages and voltage sags, demonstrated that the system could provide continuous power during utility outages and other disturbances and that it was compatible with a variety of load types found at industrial customer sites. UTILITY TEST RESULTS OF A 2-MEGAWATT, ACKNOWLEDGMENTS 10-SECOND RESERVE-POWER SYSTEM Acknowledgments Sandia National Laboratories would like to thank Dr. Imre Gyuk of the U.S. Department of Energy, Office of Power Technologies within the Office of Energy Efficiency and Renewable Energy, for support and funding of this work. ti UTILITY TEST RESULTS OF A 2-MEGAWATT, 10-SECOND RESERVE-POWER SYSTEM CONTENTS 1. 4. 6. Appendix A: Outage Mitigation Alternatives . Contents Background and Rationale. Summary of Tests. Test Site... Installation and Test Setup . Grid Synchronization/Standby and Light-Load Tests Partial-Load Tests... Introduction............. Passive Resistive and Reactive Load Loss of Utility, Full Duration .... Loss-of-Utility Test . 90% Voltage Sag Unbalanced Load and Sag Tests Operation with Partial Capacity. Repetitive Discharge Tests . Resistive and Capacitive Load .. Capacitor Switching Test. Loss-of-Utility Test........ Repetitive Discharge Tests. Resistive and Rotating Machine Load. Loss-of-Utility Test . Motor Starting ......... Repetitive Discharge Tests . ASD, Resistive and Single-Phase Electronic Loads.. ASD Outage Tests...... 90% Voltage Sag Test Repetitive Discharge Tests ............000++ Electronic Load Outage and Sag Tests Full-Load Tests.. Ten-Second Tests Short-Duration Tests .. System Design and Operation Implications from Test Results System Design Ratings Reconnection Logic ....... Switch Commutation Impacts Synchronizing with Utility/ Oscillations . Frequency Detection .. Energy Loss Savings .. Energy Management/Power Quality Multimode Operation Energy Storage Technology Conclusions and Further Research... Diesel Integration ...........2eeese Medium- Voltage Interconnection Alternative Storage Technologies Parallel Generation References.......cccccseereesscsrerceecescseeeeeseeeeenees tii UTILITY TEST RESULTS OF A 2-MEGAWATT, CONTENTS 10-SECOND RESERVE-POWER SYSTEM Appendix C: List of Tests... Figure ES-1. Test Facility Layout. .........c.cecccsesssessssesessesssessseecseseesesesieseeeeeaeaeeneaees Figure ES-2. Load Transfer upon Loss of Utility Source. Figure ES-3. Restoration of Utility after Outage. ............. Figure 1-1. MGTF Circuit Diagram with PQ2000 in Full-Load Position. . Figure 2-1. Partial-Load Test Configuration. Figure 2-2. 10-sec Test: System Voltage and Current Traces at Transfer. Figure 2-3. 10-sec Test: System Voltage and Current Traces During Reconnect. Figure 2-4. Sag Test: System Voltage and Current Traces During Transfer. Figure 2-5. Fast Sag Test. ........ccsccssecsssssesecsesesssscssscsesscecsueceeseeesacseeeeeeaeseeeenes Figure 2-6. Waveform Capture of R-L Test; Resistive Load Dropped at Transfer... Figure 2-7. Transfer Created by 12-kV Capacitor Switching on, with No Other Loads. . Figure 2-8. Capacitor Strike on Loads Served During PQ2000 Discharge. Figure 2-9. Transfer with 300-kVAR Capacitive Load.. Figure 2-10. Transfer with Motor and Resistive Loads. Figure 2-11. Utility Reconnection with Motor and Resistive Loads. . Figure 2-12. Motor Current Oscillations During Resynchronization. Figure 2-13. Unloaded Motor Starting During Discharge....... Figure 2-14. Current Drop upon Loss of One of the Two ASD Power Supplies. Figure 2-15. Transfer with ASD Load Onlly................. Figure 2-16. Utility Reconnect with ASD Load Only. Figure 2-17. Load Current Oscillations During Utility Resynchronization Stage... Figure 2-18. Transfer with Electronic Loads and 25-kW Resistor. Figure 3-1. Test Configuration for 2-MVA Load Testing. Figure 3-2. Failed Reconnect Attempt. . Figure 3-3. Transfer During 2-MW, 10-sec Outage Test... Figure 3-4. Utility Reconnect During 2-MW, 10-sec Outage Test. . Figure 4-1. Out-of-Phase Reclose on Decaying Motor Load. Figure 4-2. Motor Current Oscillations. Table ES-1. List of System Tests.. Table 1-1. Summary of PQ2000 Prototype Tests* 1-2 Table 1-2. Test Facility Breaker Assignments 1-3 Table 1-3. Auxiliary Load Measurements... 1-5 Table 2-1. Full-Duration Discharge; 500-kVA Resistive and Inductive Loads 2-2 Table 2-2. Ten-Second Outage; 500-kVA Resistive/Inductive Loads.. - 2-2 Table 2-3. Voltage Sag Test With Nominal 500-kVA R/L Load... 2-4 Table 2-4. Capacitor Strike Tests .0........secessssesecseseseeeseeeeseseeeneaes -2-7 Table 2-5. Loss-of-Utility Tests with Resistive/Capacitive Loads. Table 2-6. Loss-of-Utility Tests Serving Motor Loads............... Table 2-7. Summary of Outage Tests with ASD Loads....... Table 3-1. Summary of Full-Power, 10-Sec Outage Tests... Table 3-2. Summary of Results from 30 Short-Duration Discharges at Full Load . Table 4-1. Utility Reconnection Schemes for Energy Storage Systems. Table 4-2. UPS Energy Loss Processes .. Table 4-3. Energy Loss Assumptions Table 4-4. Sample Energy Loss Calculation for 1-MW UPS .........:cssssssessesssssessseessesesessescsececesseecsussesececscscseseeesseeeese, 4-6 iv UTILITY TEST RESULTS OF A 2-MEGAWATT, 10-SECOND RESERVE-POWER SYSTEM ACRONYMS Acronyms ASD adjustable speed drive DOE Department of Energy ESS Energy Storage Systems HVAC heating, ventilation, and air conditioning MGTF Modular Generation Test Facility ms milliseconds MVA mega volt-amp MW megawatt PCS power conditioning system PG&E Pacific Gas and Electric Company PS power supply R/L resistive/inductive load RMS root mean square SCR silicon controlled retifier SMES superconducting magnetic energy storage SNL Sandia National Laboratories SOc state-of-charge UPS uninterruptible power supply VAC volts alternating current VAR volt-amp reactive UTILITY TEST RESULTS OF A 2-MEGAWATT, ACRONYMS 10-SECOND RESERVE-POWER SYSTEM This page intentionally left blank. vi UTILITY TEST RESULTS OF A 2-MEGAWATT, 10-SECOND RESERVE-POWER SYSTEM EXECUTIVE SUMMARY Executive Summary An advanced “off-line” reserve-power system capable of supporting 2 MW of load for 10 secs was evalu- ated in 1996 by Pacific Gas and Electric Company at its test facility in San Ramon, California. The project was supported by the U.S. Department of Energy (DOE) Energy Storage Systems (ESS) Program under a contract from Sandia National Laboratories (SNL). The system was developed under a DOE Cooperative Agreement with AC Battery Corporation of East Troy, Wisconsin. The system featured a container housing 384 low- maintenance, lead-acid batteries; a high-speed static transfer switch; and control circuitry, which enabled it to detect utility source disturbances and isolate and support critical customer electric loads. It enabled mission-critical loads at industrial facilities to “ride through” momentary outages. Novel design elements included: e Short-term component ratings, enabling the sys- tem to be designed for a much lower cost than a system designed for comparable loads at con- tinuous duty; e A sophisticated monitoring feature that triggered operation during utility-voltage sags, swells, transients, and outages; e High-speed transfer capability, enabling the sys- tem to isolate loads and ramp to full power within one-quarter cycle (4 milliseconds); ¢ Control circuitry that provided resynchronization with the utility grid once restored to normal; e¢ A monitoring computer, which reported detailed status and diagnostic information. Testing was intended to demonstrate system perform- ance using a wide variety of load types and operating conditions that would be found at customer sites in the field. These tests, summarized in Table ES-1, included operation at partial load and full load, and included simulated utility outages and voltage sags. As shown in Figure ES-1, the facility provided for testing with resistive, reactive, rotating, capacitive, and electronic loads. A typical load transfer is shown in Figure ES-2. The second trace shows the utility voltage dropping to zero — a simulation of a utility outage caused by opening a line-side breaker (identified as Breaker 52- 20). The third trace shows that voltage at the load is supplied by the system after the utility is lost, and that only a minor change in the waveform at the moment of transfer is observed. The fourth and fifth traces represent utility- and load-side current waveforms, respectively. Figure ES-3 shows the corresponding waveforms as the utility is restored (by closing Breaker 52-20, thus simulating the return of utility power). Table ES-1. List of System Tests Test Dates, 1996 Tests April 15-24 Installation, interconnection and protection 2 April 24-25 Grid synchronization/standby and no-load tests June 6-July 29 _— Partial-load tests (500 kVA) 3.1 Passive-resistive and reactive loads 3.2 Resistive and capacitive loads 3.3 Resistive and rotating machine loads 3.4 Adjustable speed drive (ASD), resistive, and various single- phase and electronic loads 4 August 6-21 Full-load tests (2 MVA) 41 Ten-second tests 4.2 Short-duration tests ES-1 UTILITY TEST RESULTS OF A 2-MEGAWATT, EXECUTIVE SUMMARY 10-SECOND RESERVE-POWER SYSTEM 800A MGTF grid bus SaaS 52-16 2MVA 800 A island bus —™ rented load (» -— 300 300 300 400 600 s2-15( 52-3 ( se-t4( s2-7( kW kW kW_kW__kW Po Node #1 YH PTs CTs | Crt Pa Node FOPCS asp motor \ (ce i 52-20 TIOKVA soo kVA 100 KVA a 400 impedance loop 52-25 — — AR kW pa CB-3 EO mm 52-27 2000 A kvar’ | rN a ( ce smart sub transformer Alternate parallel loads static switch PQ-2000 4: = ™ 7 Cane EVA 150 KVAR Figure ES-1. Test Facility Layout. aad 1 C:\GREG\PG&E\PQ2000\ TEST S\WAVEBOOK\R&LSAGS\7221ST... Fae] ES To. Options H Figure ES-2. Load Transfer upon Loss of Utility Source. The testing demonstrated that the system could be used to provide continuity of power during momen- tary utility outages and other disturbances, and that it was compatible with a variety of load types found at industrial customer sites. A number of lessons were learned with respect to the design and application of off-line reserve-power sys- tems that utilize energy storage. Some of the issues that were identified led to on-site design modifica- tions of the prototype itself, some led to improved designs for subsequent generations of the PQ2000, and some remain for the marketplace to resolve. The issues include: e System Design Ratings. The optimal unit size ratings (in both power and time) remain elusive. Performance ratings are somewhat conservative because the field experience is still limited. True ratings would couple power and time (MW- seconds) because the design constraints are largely driven by component heating. e Reconnection Logic. While the testing demon- strated that off-line designs can support momen- tary outages within the design performance ES-2 UTILITY TEST RESULTS OF A 2-MEGAWATT, 10-SECOND RESERVE-POWER SYSTEM 473.235 EXECUTIVE SUMMARY 5227RMS 3 486.0352 v 14s 794.3707 ‘L966 6015 y Lis Figure ES-3. Restoration of Utility after Outage. envelope, it is not clear how the system should respond when the outage is approximately equal to the system temporal rating. For example, if the utility is restored while discharging but it does not have adequate time to resynchronize, should the system transfer the load back to the utility out-of-phase in order to provide continuity of power? Switch Commutation Impacts. Certain sensitive loads tripped off-line during the transition from the utility source because the transfer scheme re- quires a momentary overvoltage condition. While the magnitude of the overshoot has been reduced for subsequent designs, the manufacturer and customer should coordinate protection settings as a normal activity during installation to prevent unnecessary loss of load. Synchronizing with Utility/Oscillations. Some oscillations were observed during the resynchro- nizing periods before the utility was restored. Such oscillations can generally be expected with loads that react dynamically to supply frequency variations. Frequency Detection. Under certain conditions, rotating loads were observed to generate back- electromotive force on the load circuit during a utility outage. The presence of voltage initially confounded the utility-monitoring circuitry. To accommodate this situation, frequency detection was added in determining whether protective ac- tion is necessary. 75.1171 | A 1m s | Energy Loss Savings. The off-line design ap- proach results in a significant cost savings to the customer by eliminating demand and energy charges associated with rectification and inver- sion losses. These benefits are estimated to be nearly $300/kW, which is as much as one-third of the total capital cost. Energy Management/Power Quality Multimode Operation. While combining multiple economic benefits is attractive, various technical and cost hurdles will have to be overcome in a multimode design, particularly in the case of off-line sys- tems, which incorporate short-term component ratings. Energy Storage Technology. While the system revealed no shortcomings in the battery compo- nent, the utility power source industry in general faces enormous challenges with respect to sys- tems requiring longer-term storage. Advanced battery technologies promise greater reliability and consistency for these applications. A number of follow-on research activities are sug- gested, given the current stage of power quality tech- nology and the market requirements. These include integration of an off-line system with diesel genera- tion, interconnection at medium voltage (e.g., 12 kV), assessment of alternative storage technologies, and the operation of multiple off-line systems in parallel. ES-3 UTILITY TEST RESULTS OF A 2-MEGAWATT, EXECUTIVE SUMMARY 10-SECOND RESERVE-POWER SYSTEM This page intentionally left blank. ES-4 UTILITY TEST RESULTS OF A 2-MEGAWATT, 10-SECOND RESERVE-POWER SYSTEM OVERVIEW 1. Overview Background and Rationale A prototype model of an advanced facility-level backup power system was evaluated during the sum- mer of 1996 by Pacific Gas and Electric Company (PG&E) at its test facility in San Ramon, California (Norris, 1996; and Ball, 1996). The system was de- signed and manufactured by AC Battery Corporation, and development support was provided by the U.S. Department of Energy (DOE) and Sandia National Laboratories.” This 2-MW system, given the product designation PQ2000, was derived from an earlier grid-connected battery energy storage system, also manufactured by AC Battery, which was designed to support peaking power requirements on utility distribution systems or customer sites. This previous system housed low- maintenance, lead-acid batteries and power electron- ics and controls in a modular container, rated at 250 kW and 167 kWh. It was designed for a 480-V, three-phase interconnection. The PQ2000 utilized most of the mechanical design features of the earlier energy storage system, includ- ing the structural housing, internal racking, hydrogen ventilation, cooling, safety alarms, and controls. The new design, however, included a high-speed “static switch” and control circuitry, which enabled it to isolate critical customer electric loads and support them in the event of utility-side power disturbances. The PQ2000 therefore was designed to operate as a voltage source for an isolated load, and had a net system rating of 2000 kVA. One of the key test objectives of this study was to verify that the PQ2000 could operate as a bridge be- tween the time of the utility outage and the startup of a diesel engine generator. Although the cost of the engine generator and the development of the control integration precluded a comprehensive demonstration of this application, it was reasoned that the most criti- cal aspects would be the operation of the static switch and the capability of the system to maintain its full 2- MW output for the bridging time of about 10 sec- onds. The prototype was rated for 10 seconds whereas subsequent units were rated at 15 seconds. * Final Report on the Development of a 2MW/10 Second Bat- tery Energy Storage System for Power Disturbance Protec- tion. Although the prototype was not to be integrated with the diesel, the system did suggest that another niche application exists for power quality devices in a stand-alone technology configuration. The PQ2000 system could be used in applications requiring only short-term (under 10 seconds) protection, and appli- cations where the additional cost of the diesel gen- erator could not be justified. Even in these cases, the 10-second rating exceeded the typical reclosure set- tings of utility distribution systems, and it was rea- soned that about 90 percent of all utility outages could be averted without the added cost of the diesel supplement. Therefore, the PQ2000 in a stand-alone configuration potentially would have application for existing electric customers. The PQ2000 testing would be not only to validate the design ratings, but also to demonstrate the reliability and operation of the unit as a stand-alone technology. The PQ2000 design promised to take advantage of high short-term component ratings. By understanding its thermal operating characteristics over limited peri- ods, component costs could be reduced. While the original storage system was rated for 250-kW con- tinuous duty, the PQ2000 would be rated for 2,000 kW-eight times the original steady-state rating. One important goal of the PQ2000 design was the ability to reduce system hardware costs by targeting the short-term duty cycle niche application and elimi- nating the need for continuous power ratings. Most UPS designs are based on steady-state ratings and can apply power for more than 15 minutes. A 2-MW, 15- minute uninterruptible power supply (UPS) might require the entire basement of a large building, whereas, the PQ2000 could be housed in a standard 20-ft shipping container. In principle, the system could be produced and installed at a significantly lower cost than a standard UPS due to a much smaller volume of battery, the type of short-discharge battery used, and the throughput advantages of using tran- sients ratings for the power train. The PQ2000 consists of eight battery storage modules within an environmentally enclosed container, a high- speed static transfer switch, and a step-up trans- former. The system is capable of sensing a utility voltage or frequency disturbance and switching from standby to full operation in less than four millisec- onds. The high-speed transition is intended to elimi- nate the potential end-user effects of momentary out- ages, switching transients, voltage sags, and other OVERVIEW short-term disturbances to utility power. The PQ2000 utilizes a microprocessor-based controller to super- vise aspects of the system operation and is interfaced with a monitoring computer for the user. A monitor- ing computer reports status and diagnostic informa- tion and permits some user control. This report summarizes the testing and lessons learned from the prototype PQ2000 by PG&E, Inno- vative Power Systems, and Energy and Environ- mental Economics, Inc. from April through August of 1996. Key test results from this prototype have been incorporated by the manufacturer in to the second- and third-generation designs, which have since been installed on “mission-critical” loads at customer sites across the country. Summary of Tests The overall test objectives were to: ¢ Ensure that the system met the design specifica- tions of 2 MW and 10 secs; ¢ Demonstrate the system’s performance under the worst-case conditions that could take place at customer sites; and ¢ Gain installation and operational experience with the system. Table 1-1 shows a summary of the tests described in this report. UTILITY TEST RESULTS OF A 2-MEGAWATT, 10-SECOND RESERVE-POWER SYSTEM Test Site Testing was conducted at PG&E’s Modular Genera- tion Test Facility (MGTF) in San Ramon, California. An electrical diagram of the test facility (Figure 1-1) shows the location of the prototype PQ2000 (on the low-voltage side of the “Smart Substation” trans- former), a 2-MW resistive load (Breaker 52-24), a resistive/reactive load (52-17), an electronic load (52- 15), a capacitive load (52-14), and a motor load (shown as the “Gen-Set” on 52-3). The system’s position in this configuration permits full loads of 2 MVA because it is connected on the 1600-Amp smart-sub bus. Another position, labeled in Figure 1-1 as “Alternate PQ2000 Location,” is used for partial-load tests and permits the variation of the 480-Vac bus voltage. The “Impedance Loop” shown in Figure 1-1 is a vari- able series impedance used to create voltage-sag con- ditions. In addition to the bus voltage variations, the partial-load tests were designed to evaluate a wide range of load types, as illustrated in the figure. The project did not have the resources to test such a vari- ety at the full 2-MVA capacity. Table 1-2 lists the MGTF breakers and associated test equipment used during the test program. a ——————————————$——$— $$$ ———————— —scece iii Table 1-1. Summary of PQ2000 Prototype Tests* Test Dates, 1996 Tests 1 April 15-24 ¢ _ Installation, interconnection and protection 2 April 24-25 ¢ — Grid synchronization/standby and no-load tests 3 June 6-July29 e —_ Partial-load tests 3.1 — Passive-resistive and reactive loads 3.2 — Resistive and capacitive loads 3.3 — Resistive and rotating machine loads 3.4 — Adjustable speed drive (ASD), resistive, and various sin- gle-phase and electronic loads 4 August 6-21 e Full-load tests 41 — Ten-second tests 4.2 — Short-duration tests * A detailed list of the tests that were performed is included in Appendix B. ieee ener a a 1-2 UTILITY TEST RESULTS OF A 2-MEGAWATT, 10-SECOND RESERVE-POWER SYSTEM OVERVIEW 52-2 GRID BUS 800 A bus —~ a i 1 Met Bldg Loads from AD ) 52-1 Diablo Division . : 52-8 : i 10( face ( ( an ( VoltiFreq Wie w/52-25 Relay Package interrupter Motor 4 - Control 480V/21kV : Center 500 kVA 2 i 52-12( / PV Inverter ; Fuel Cell PCS MODULAR GENERATION nil Intlck 70 kVA 1 110 kVA TEST FACILITY - ee : Gnd Bank ISLAND BUS to 52-2 Transfer 7 Seg | Switch i 52-14( 52-15( 52-16( 52-17( Intick 52-3 ( wis2-12 ! | = c > interrupter PV Simulator Gen-Set Capacitor Load Banks Bank 196 kVA 400 kW 300 KVAR 480V/21kV Volt/Freq 1MVA Rela) 52-20 A Y 52-28 Impedance loop | 52-25 2000A 2 Cc oi 7 _ 800 A bus 1600 A bus o Intick ee Intick CB-3 | ae w/S2-27 59.97 t w/52-9 ) Pre a She 2400A/8s A Og cea 1 c8-2( ee Gnd Gnd | Alternate Relay Relay Lf PQ-2000 LL. + Location Lal static SMART SUBSTATION Eu x switch Load Banks = PM-250 : Battery To 2000 kVA t PQ-2000 Figure 1-1. MGTF Circuit Diagram with PQ2000 in Full-Load Position. Table 1-2. Test Facility Breaker Assignments Breaker Assignment 52-17 Existing 400-kW — 300-kVAR load banks 52-16 Connection between MGTF and smart-sub bus 52-15 DC simulator (12-pulse ASD-type load) 52-14 Capacitor bank via 12-kV transformer 52-3 Motor generator set and load bank 52-7 Fuel cell inverter 52-20 Main electrical entrance to smart sub 52-24 Dummy breaker (removable shunt bus) serving rented resistive load banks 52-25/52-28 Impedance loop input and output 52-27 Impedance loop bypass 1-3 OVERVIEW Installation and Test Setup The PQ2000 was shipped from the manufacturer in East Troy, Wisconsin, using a low air-ride trailer, installed onto a previously prepared foundation, and connected electrically to its test breakers. The system was inspected to verify that it was in good condition after shipment, that it was properly installed and interconnected with the facility grid, and that it met all of its defined safety and protection require- ments. These preparations were performed through April 24, 1996. 1. Load bank connections. Five rented load banks totaling nearly 2 MW in resistive load were con- nected to the output of the system via a dummy breaker (52-24) in the smart-sub switchgear. These loads included three 300-kW banks, one 400-kW, and one 600-kW bank. Additional re- sistive and inductive loads totaling 500 kVA were provided by facility load banks connected via Breaker 52-17 on the MGTF bus. The con- nections to these loads, shown in Figure 1-1, were checked and verified by facility personnel. 2. Remote emergency stop. A switch was added from the PQ2000 to the control room for emer- gency shutdown of the system. This provides extra protection for emergency situations in which the utility Breaker 52-20 has been opened, and PQ2000 is to be prevented from operating. 3. Instrumentation. High-speed data acquisition instrumentation was connected to measure pa- rameters on both the utility and the load side of the PQ2000 system. 4. Rotation. The correct electrical rotation for the facility (A-C-B) was established at the system connection. Measurements showed that the smart-sub 480 Vac rotation was in fact A-B-C, and not A-C-B, indicating that the phases were reversed either at the transformer or at the 21-kV service to the facility. The PQ2000 is designed to be rotation-indifferent because it operates as three independent phase sources. This was veri- fied by running two small discharges with the B-C phases in normal and switched positions. 5. Hi-pot tests. Sensitive components were isolated as defined by the manufacturer to facilitate hi-pot tests on the 2000-kVA isolation transformer. UTILITY TEST RESULTS OF A 2-MEGAWATT, 10-SECOND RESERVE-POWER SYSTEM The test confirmed that there were no shorts or leakage problems in the transformer or cable in- sulation between the system and utility. Grid Synchronization/Standby and Light-Load Tests The following tests were performed to safely bring individual system components and the complete sys- tem to an operational state. These tests were per- formed and approved from April 24 through 25, 1996: 1. Safety and protection. Performed visual inspec- tion, verified safety alarms and control functions, and checked communications (shunt trip, alarms to switchgear, lights, modem operation, etc.). 2. Static switch communications. Verified that fiber-optic communications between the battery container and static switch were working prop- erly. The system initially failed this test because a jumper fiber for the backup diesel option was missing, having been lost during the packing or shipping. This fiber was replaced, and a subse- quent test verified correct communications. Other tests were performed to ensure that the system would fault properly given the loss of one of the seven communication fibers between the static switch and PQ2000 container. All but one occurred without problem. When the PQ-Run signal fiber was pulled, the fiber connector was exposed to sunlight, causing the PQ2000 to acti- vate even as the static switch was still gating its switches to the utility. This caused the two volt- age sources to exist simultaneously, and a fault current was created from the potential difference. The fault tripped open Breaker 52-27. Shielding the signal fiber resulted in proper fault operation. 3. Container pre-charge. Completed two succes- sive and complete equalization charge cycles for all of the eight PQ2000 modules, following pro- cedures defined by the manufacturer. 4. Static switch synchronization. Verified the op- eration of the static switch and container using a light (about 250-kVA) load. Performed a load transfer from the utility to the PQ2000. Tested the synchronization function and ensured that the switch would not close on an unsynchronized utility. 1-4 UTILITY TEST RESULTS OF A 2-MEGAWATT, 10-SECOND RESERVE-POWER SYSTEM OVERVIEW The system passed this test, but the reconnection duration (the elapsed time between the restora- tion of the utility supply and reconnection of the load to the utility) was recorded for as long as four seconds. The manufacturer noticed a soft- ware error related to the counter used to monitor the frequency excursion between the utility and system, and modified the code. This resulted in a significant improvement in the reconnection duration. Static switch fault detection. Created a fault on the static switch by manually disabling it. Veri- fied that the PQ2000 set the proper fault on the operator display and sent a fault message to the monitoring computer. Auxiliary load measurements. While the static switch and the PQ2000 were synchronized with the utility, and they were supplying a light resis- tive load, the continuous system power draw to the PQ2000 was measured using a BMI 3030 monitor connected between the PQ2000 and Cir- cuit Breaker 2 (CB-2) of the static switch. Recordings were made of the container’s primary auxiliary loads, which include a heater, two sets of air-conditioners, and a hydrogen blower. These loads are characterized in Table 1-3. Table 1-3. Auxiliary Load Measurements Container Status Vv | kVA Load No HVAC 201 2.6 0.5 Heater On 200 29 5.8 AC 1&30On 201: 19.2 3.9 AC 1,2,3&4On 200 35 7.0 1-5 UTILITY TEST RESULTS OF A 2-MEGAWATT, OVERVIEW 10-SECOND RESERVE-POWER SYSTEM This page intentionally left blank. UTILITY TEST RESULTS OF A 2-MEGAWATT, 10-SECOND RESERVE-POWER SYSTEM PARTIAL-LOAD TESTS 2. Partial-Load Tests Introduction The prototype PQ2000 system was tested using a wide variety of load types at partial-load levels (500 kVA maximum). These tests were designed to simulate possible loads and operating modes that could be seen in the field at customer sites. These tests were performed between June 5 and July 29, 1996. During the course of testing, the manufacturer made certain changes to the design of the voltage detection circuitry, control logic, and other components that were necessary for the system to perform satisfacto- rily in particular tests. A final series of tests were run after all such changes were implemented, and the test results for this final series are reported here. In order to characterize the PQ2000’s ability to serve a variety of customer loads, the partial load tests were split into four steps, each using a different type of load: (1) passive resistive and reactive load, (2) re- sistive and capacitive load, (3) resistive and rotating machine load, and (4) a combination of adjustable speed drive (ASD), resistive, and various single- phase and electronic loads. In addition to load-specific characteristics, the first set of tests covered general aspects of the system’s operation, such as recharge and operation with fewer than eight modules. —— MGTF grid bus pains A island bus (s27 52-15( 52-3( a 52-17 FC PCS ASD motor Mpa(sou() san() (sess PQ Node #2 110 KVA 300 400 190 kVA 100 kVA KVAR kW 300 1 kKVAR > PQ-2000 oe th c8-2( — static | switch 150 KVAR 2000 kVA Figure 2-1. Partial-Load Test Configuration. )ee-1 The PQ2000 was connected at the partial-load-test location detailed in Figure 2-1 for all of the tests de- scribed in this section. Passive Resistive and Reactive Load These tests were performed using parallel 400-kW and 300-kVAR load banks, totaling 500 kVA and connected on Breaker 52-17 (all other breakers were open during these tests). Loss of Utility, Full Duration This test was designed to determine the system response to a loss of utility condition and the maxi- mum discharge duration given an indefinite outage. Two representative tests are described in Table 2-1. The system is rated to ensure that there will be sus- tained service to a load if an outage as long as 10 secs in duration occurs. It is therefore designed with ample margin to allow time for synchronization and reconnection to the utility once the outage is over. Long outages of up to 30 secs were used to determine the maximum time the system discharges before it shuts down. PQ Node #1 impedance loop 52-25 1600 A bus, 52-20 20 at - 522d 2000 A smart sub transformer 2 MVA rented load 350 350 350 400 600 kW kW kW kW kW 2-1 PARTIAL-LOAD TESTS UTILITY TEST RESULTS OF A 2-MEGAWATT, 10-SECOND RESERVE-POWER SYSTEM Table 2-1. Full-Duration Discharge; 500-kVA Resistive and Inductive Loads 3-Phase Outage Discharge vet Date Load Duration ie Duration Comments . (kVA) (sec) (sec) 1 7/22 500 30 2.5 13.4 After discharge, container and static switch shut down from loss of supply. 2 7/22 500 12.2 3 13.0 System did not synchronize in time to reconnect to grid. Failed to recharge after this test. =—— ooo These discharges were typically around 13 secs as indicated. Test 2 illustrates an outage that lasts for fewer than 13 secs but that is too long for the system to adequately recognize, synchronize, and reconnect to the restored grid supply. Loss-of-Utility Test This test was performed to characterize the operation and speed of response of the PQ2000 to a rated 10- second loss-of-utility condition. A typical response is described in Table 2-2. In this test, 1.1 secs tran- spired between the time the utility was restored and the time that the system reconnected the loads to the grid. Table 2-2. Ten-Second Outage; 500-kVA Resistive/Inductive Loads 3-Phase Outage Test Load Duration Response No. Date (kVA) (sec) t (ms) 1 7/22 500 10.2 2.8 Figures 2-2 and 2-3 show system voltage and current traces recorded using a PC-based data acquisition and graphing package during the 10-sec test. The traces shown in this plot, as well as most subsequent plots, are identified as follows: Trace 1: Utility voltage phase A rms (Labeled 5227RMS) Trace 2: Utility voltage phase A (Labeled 5227Vab) Trace 3: Load voltage phase A (Labeled 5216Vab) Trace 4: Utility current phase A (Labeled 5227Ia) Trace 5: Load current phase A (Labeled 5216la) Figure 2-2 shows the utility outage and transfer of load to the PQ2000 system. The voltage overshoot created by the PQ2000 to disconnect the utility (by commutating [turning off] the conducting static switch) is evident in the load voltage, 5216Vab. At that point, the utility current (5227Ia) drops off, and the load is maintained by the battery system. Figure 2-3 shows the PQ2000 reconnecting the load to the utility 11 secs later. This is indicated by the return of utility-supplied current 5227Ia. The utility voltage (5227Vab) had returned a second earlier. 90% Voltage Sag This test characterized the system response to a util- ity-side voltage sag to 90% of nominal voltage, thus simulating another type of disturbance that the PQ2000 was designed to mitigate. The voltage sag was artificially introduced by opening Breaker 52-27 (see Figure 2-1) so that current flowed through the reactive elements in the impedance loop. Because of the test configuration, once the PQ2000 assumed the load, the utility load dropped to zero, and its voltage returned to normal (the current through the impedance loop dropped to zero). Therefore, in order for this test to be carried out, the static switch reconnect settings were changed to force a minimum run time of 2 secs. Without this tempo- rary modification to the control logic, the PQ2000 would immediately restore the “normalized” utility source, causing a rush of current through the induc- tors, and the subsequent voltage sag would result in another load transfer — the PQ2000 would cycle rapidly between the two sources. UTILITY TEST RESULTS OF A 2-MEGAWATT, 10-SECOND RESERVE-POWER SYSTEM Pl ee LL EG\PG&E\PQ2000\TESTS\WAVEBOOK\R&LSAGS\722TST PARTIAL-LOAD TESTS Figure 2-2. 10-sec Test: System Voltage and Current Traces at Transfer. GH PostView 1.3 -- C:\GREG\PG&E\PQ2000\T ESTS\WAVEBOOK\R&LSAGS\722TST [= (o[x} 745.1191 A ims Figure 2-3. 10-sec Test: System Voltage and Current Traces During Reconnect. One sag test (summarized in Table 2-3) was per- formed by slowly lowering the voltage to the trip point, so that the trip point could be accurately meas- ured. The system tripped at just under 432 Vac, cor- responding precisely with the design rating of 90% of 480 Vac. The measured load was less than 500 kVA because it was proportional to the lowered supply voltage. The discharge duration was not captured by the instrumentation for this particular test. Figure 2-4 shows the load transfer to the PQ2000 with the phase A voltage around 432 Vac. Note that the utility voltage (5227RMS) increases immediately as the load is dropped (the voltage increase is instan- taneous, but the measurement reflects the instru- ment’s 10-cycle averaging of the RMS voltage). Five subsequent sag tests were successfully per- formed by rapidly dropping the voltage to below 90%. The tests were conducted by rapidly increasing PARTIAL-LOAD TESTS UTILITY TEST RESULTS OF A 2-MEGAWATT, 10-SECOND RESERVE-POWER SYSTEM Table 2-3. Voltage Sag Test With Nominal 500-kVA R/L Load Test 3-Phase Load Response t Trip No. Date (kVA) (ms) Voltage 1 7/22 425 2.8 ~432 Vac fae PostView 1.3 -- C: i a ENT au yeh j Figure 2-4. Sag Test: System Voltage and Current Traces During Transfer. the line impedance in the impedance loop from its lowest setting (Step 1) to its maximum setting (Step 3). This effectively dropped the load voltage from a phase average of around 450 Vac to below 430 Vac. Each discharge lasted approximately two seconds. The impedance loop setting was switched back to Step 1 during the discharge to prevent a subsequent sag from occurring when the utility was reconnected. Figure 2-5 shows the transfer from one of the fast sag tests. The sag (with averaging delay) is evident from the top trace, which is the utility phase A rms voltage. The load voltage (5216Vab) shows an almost imper- ceptible change as the battery system assumes the load. A slight increase in high-frequency harmonics is noticeable after the transfer. Unbalanced Load and Sag Tests These tests were performed on June 29, 1996, to characterize the response of the PQ2000 to an unbal- anced load under a sag condition. The static switch was again set so that a two-second delay occurred between the time a normal utility voltage is detected and the system transfers load back to the utility. The test personnel determined that the best method for creating the imbalance was to remove a phase leg from one of the impedance loop-step contactors. Two successful tests were performed in this manner, veri- fying the PQ2000’s response to a sag in only one phase. The test was not repeated on other phases. Operation with Partial Capacity These tests were performed to verify the PQ2000’s ability to transfer and serve partial-capacity loads with one or more modules out of service. The con- tainer was designed to handle 500 kVA of load with as few as three modules operating. The capability was verified by the following tests, all with 500-kV resistive and inductive load, on June 6, 1996. 2-4 UTILITY TEST RESULTS OF A 2-MEGAWATT, 10-SECOND RESERVE-POWER SYSTEM PARTIAL-LOAD TESTS [785.4492 | .791.2006 | 813.5743 Figure 2-5. Fast Sag Test. 1. One module disabled (Module 1) 2. Three modules disabled (Modules 1, 5 and 7) 3. Five modules disabled (Modules 2, 3, 4, 6 and 8) Repetitive Discharge Tests A series of 43 repetitive, short-duration discharges were performed to characterize the overall reliability of the system. Each test was an outage averaging one to two seconds in duration and supporting the full 500-kVA resistive/reactive load. The tests were per- formed in sets of four, with a recharge period be- tween each set. The sets were viewed as “worst case” multiple short-duration power outage scenarios. The resistive load was dropped temporarily during transfer on at least five of the 43 tests. The bank’s over-voltage relay occasionally tripped the load as a protective measure in reaction to the PQ2000 voltage overshoot. The resistive bank also tripped once toward the end of a discharge; however, this was attributed to an over-temperature condition in the bank itself. Thus, it became evident that customers using equipment sensitive to such an overshoot should review and possibly adjust the protection set- tings. The system failed to recharge following the first set of four outages. As a result, the system cut out during the fifth outage, and the load was dropped. A "Container Over Temperature" warning was noticed on the monitoring computer at the end of the 43 repetitive tests. It was later discovered that all four container air-conditioner breakers had tripped sometime during the testing, but it is not known exactly when. The warning itself is not cause for a shutdown, which would have occurred if the tem- peratures had exceeded a higher set of limits. The tests therefore confirmed proper operation of the temperature warning indicator. The system was later modified by the manufacturer to revise the charge-control software and replace the container air-conditioner circuit breakers, which corrected both of the described problems. Figure 2-6 shows an example of a waveform from a test in which the resistive bank was shut down by its over-voltage relay. The overshoot can be seen in the negative cycle of the load voltage (Breaker 52-16). The dropped load is apparent from the decrease in load current (bottom trace) as the load stabilizes approximately five cycles after the transfer. This plot also illustrates how the voltage harmonics increased during the unstable transition and in response to a specific load. As the waveform stabi- lizes five cycles after the transfer, the load current to the inductive load is very low in harmonics, but the supply voltage created by the PQ2000 through its capacitors experiences a slight resonance at the switching frequency. It exhibits a marked difference from the voltage waveform shown supplying the load in Figure 2-7. 2-5 PARTIAL-LOAD TESTS UTILITY TEST RESULTS OF A 2-MEGAWATT, 10-SECOND RESERVE-POWER SYSTEM 466 5967 5227RM | 467.1387 Vv -62.496ms r + } 795.9229 [7 [785.4493 © -go0.0973 f es00301 | Biase ae pete ea -62.496ms 486.3282 v "7 -62.496ms w-be-b eld 5227la_ =f 0.976562 A -226.5625 Ao A poop tp pepe -62.496ms Figure 2-6. Waveform Capture of R-L Test; Resistive Load Dropped at Transfer. Resistive and Capacitive Load These tests used the 400-kW resistive load bank and a 12-kV, 300-KVAR capacitor bank connected via a step-up transformer from the 480-V bus. The capacitors were isolated on Breaker 52-14 to accom- modate capacitor switching tests. Capacitor Switching Test These tests were performed to determine whether the PQ2000 is activated as a result of a voltage spike from capacitor switching. The tests were intended to simulate the field condition of utility capacitor switching on the distribution line feeding the cus- tomer. Two types of transients were performed using the capacitor. The switch can be closed on either side of the transformer. Switching on the 480-V side creates a transient that includes the energization of the trans- former, and is a more severe disturbance. The trans- former is already energized when switching on the 12-kV bus; therefore, this method better replicates an actual feeder capacitor switch. On July 23, 1996, a total of six strikes were per- formed from the 12-kV bus and one on the 480-Vac bus. In addition, four strikes were tested while the PQ2000 was serving the load, simulating a capacitor energizing on the load side of the PQ2000. All of these tests are summarized in Table 2-4. The 250-kVA loads were 200-kW resistive and 150-kVAR inductive, while the 335-kVA loads were comprised of 200-kW resistive and 150-kVAR in- ductive. As shown in the table, all of the strikes but two were significant enough to cause the PQ2000 to discharge and assume the load—albeit for very short durations. The two strikes that did not cause a dis- charge were performed with light load on the 12-kV line late in the afternoon. The previous 12-kV strikes (with loading) that caused a discharge were in the morning, when the service voltage at the MGTF is typically higher. Figure 2-7 shows the transfer that occurred in the afternoon during a 12-kV strike with no load. The current shown in 5216la is the capacitor coming on while the current from the utility shuts off. The strike itself can be seen in the 5227RMS trace at the top of the plot. Note that the utility voltage decreases after losing the 150-kVAR PQ2000 capacitive load. These results confirm the benefit of off-line backup power systems with energy storage such as the PQ2000: the system is able to provide ride-through 2-6 UTILITY TEST RESULTS OF A 2-MEGAWATT, 10-SECOND RESERVE-POWER SYSTEM PARTIAL-LOAD TESTS , 71027.954 f f Ws A Figure 2-7. Transfer Created by 12-kV Capacitor Switching on, with No Other Loads. Table 2-4. Capacitor Strike Tests 3 Phase Outage Test Load Duration Strike No. Date (kVA) (sec) Voltage Comments 1 7/23 250 <1 12 kV Discharged 2 7/23 250 <1 12 kV Discharged 3 7/23 250 <1 12 kV Did not discharge 4 7/23 250 <1 12 kV Did not discharge 5 7/23 0 <1 12 kV No load conditions; discharged 6 7/23 0 <1 12 kV No load conditions; discharged 7 7/23 250 <1 480 V Discharged 8 7/23 335 ~5 12 kV Strike on load during a 5-sec outage 9 7/23 335 ~5 12 kV Strike on load during a 5-sec outage 10 7/23 335 ~5 12 kV Strike on load during a 5-sec outage 1 7/23 335 ~5 480 V 480-Vac strike on load during a 5-sec outage during all types of utility disturbances, including out- ages, sags, and overvoltage conditions (within the storage capabilities of the system). Figure 2-8 shows a 12-kV strike that was incurred while the PQ2000 was discharging into a 335-kKVA load. This plot shows only the voltage and current to the load, traces 5216Vab and 5216Ia. A tremendous current spike is seen at the load while it is supplied by the PQ2000. Nevertheless, the system maintained the load without incident following the transient. Loss-of-Utility Test These tests were performed to characterize the opera- tion and speed of response of the PQ2000 serving a resistive-capacitive load following a complete loss- of-utility condition. Two successful 10-sec carry- overs were performed and are summarized in Table 2-5. In each, the PQ2000 continued to dis- charge for approximately 1.1 secs after the utility voltage was restored, and then it reconnected the loads to the utility. PARTIAL-LOAD TESTS 873.34 UTILITY TEST RESULTS OF A 2-MEGAWATT, 10-SECOND RESERVE-POWER SYSTEM 2033.105 , at Figure 2-8. Capacitor Strike on Loads Served During PQ2000 Discharge. Table 2-5. Loss-of-Utility Tests with Resistive/Capacitive Loads 3-Phase Outage Test Load Duration Response t No. Date (kVA) (sec) (ms) 1 7/23 500 9.82 3 2 7/23 500 9.97 3 Figure 2-9 shows the load transfer to the PQ2000 during one of the 10-sec outage tests, with a 300-kKVAR capacitive load (500-kVA total load). The oscillations on the load current shown are significant, but were typical during a transfer with such high ca- pacitive loads. The current typically stabilized after about four cycles. Repetitive Discharge Tests Repetitive short-duration discharges were success- fully performed using the resistive-capacitive loads. As in the case with the resistive-inductive loads, the discharges were performed four at a time with interim recharges after each set of four. The discharges ranged from one to two seconds in duration. Resistive and Rotating Machine Load A motor-generator set was rented to facilitate rotating load testing. The motor was connected to the supply at Breaker 52-3 and was coupled to the generator via a belt drive, which, in turn, supplied an independent resistive load bank. With the generator supplying 100 kW to the load bank, the total motor load seen by the utility was approximately 160 kVA. These tests used the facility resistive and inductive load banks individually and together with the motor to provide a variety of load combinations. Tests with the motor were performed from July 24 through 29. Loss-of-Utility Test These tests were performed to characterize the opera- tion and speed of response of the PQ2000 while it was serving the motor loads following a complete loss-of-utility condition. Table 2-6 summarizes six characteristic tests performed with a variety of load combinations and outage durations. 2-8 UTILITY TEST RESULTS OF A 2-MEGAWATT, 10-SECOND RESERVE-POWER SYSTEM PARTIAL-LOAD TESTS | -184.5703 L v 45.483ms } 999.1367 1436 621 | aa9939s 7 5227la_ 2.929687 A -49.129ms 5216la =H -74 99Sems Rios RD <I Figure 2-9. Transfer with 300-kVAR Capacitive Load. Table 2-6. Loss-of-Utility Tests Serving Motor Loads Test 3-Phase Load Outage Duration No. Date (kVA) (sec) Comments 1 7/24 160 3 Motor only (gen loaded with 100-kW resistive load) 2 7/24 160 8.5 Motor only 3 7/29 160 9.59 Motor only 4 7/29 160 12 cycles Motor only 5 7/29 160 kVA + 300 kW 10 Motor + 300-kW resistive [load?] 6 7/29 160 kVA +225 kVAR 1 Motor + 225 kVAR Figures 2-10 and 2-11 show a successful transfer and reconnect of a motor-based load with 300 kW of additional resistive load. Several interesting aspects of powering the motor loads were revealed and are described further below. Audible current oscillations occurred when the PQ2000 was serving the motor load. The oscillations themselves did not cause a loss of stability or load, but sometimes the current magnitude varied by 50% or more. This led to some concern over whether the oscillations would present a more serious problem at loads approaching the 2-MVA rating of the system. The oscillations typically occurred at two times dur- ing anevent. The first was when the battery first took the load from the utility. These dampened within one second. The second, and usually the more significant occurrence, was when the utility supply was first restored (not when the load is reconnected to the util- ity, but when the PQ2000 first detected that the sup- ply was restored). At this point, the PQ2000 began to track the utility phasing in order to synchronize. It is this tracking that caused the oscillations. Figure 2-12 shows the beginning of a current oscilla- tion in the motor (bottom trace) after the utility volt- age is restored (but before the load is transferred back). The plotting software was incapable of dis- playing a full period of oscillation on a single plot, but this period was approximately 20 cycles. The magnitude of the oscillations eventually dampened, and the utility was restored. On no occasion was there any loss of load. 2-9 UTILITY TEST RESULTS OF A 2-MEGAWATT, PARTIAL-LOAD TESTS 10-SECOND RESERVE-POWER SYSTEM C:\GREG\PG&E\PQ2000\TESTS\WAVEBOOK\MOTOR\729T ST. [23a F777 3369385 | __ 839.1357 856.9337 | 12094.238 958.496 “357.5195 1021.68 sso [I -112.493ms Figure 2-10. Transfer with Motor and Resistive Loads. ps] \PG&E\PQ2000\TES TS\WAVEBOOK\MOTOR\729TST. | 491.1914 L 4972202 f 10.7625 | 822.6000 | 5227Vab i E 32.578 236.3525 FN 10.762 5 B0EDS A 5216Vab =|} & J fe 278.3203 . v | seastea f ; 10.7625 _| 1171484 | ads Al 5227la J | r “1933125 | ! } . 11554.297_f 10.7625 Tacs [mee -129.8828 A 340.7812 10.762 ¢ 10.762 [Bitescee [eT > <Te] = iz a = Figure 2-11. Utility Reconnection with Motor and Resistive Loads. {sso | i} tin ' : 99s 588s Figure 2-12. Motor Current Oscillations During Resynchronization. 2-10 UTILITY TEST RESULTS OF A 2-MEGAWATT, 10-SECOND RESERVE-POWER SYSTEM PARTIAL-LOAD TESTS In the chart, 5227Vab shows the newly returned util- ity source voltage. The load voltage shown in the 5216Vab is the back-electromotive force of the motor load, initially low in frequency relative to the utility. At the reclose (not shown), currents from the utility and load were at fault levels. Oscillations during re- synchronization are discussed in more detail in Chapter 4, Conclusions. Motor Starting Two additional tests were performed to characterize the operation of the PQ2000 in response to a motor in-rush current while supplying load during an out- age. The motor could not be started under load, so the first test examined the motor starting without the gen- erator load, and the second test examined switching the running generator’s load from 0 to 100 kW. The PQ2000 system handled both tests successfully. Figure 2-13 shows the load voltage and current (5216Vab and 5216Ia) at the instant the motor was started, given 100 kW of additional resistive-base load on the circuit. As expected, the in-rush current was significant and tapered off after several cycles. Repetitive Discharge Tests Ten repetitive short-duration discharges, each lasting one to two seconds, were performed with the motor and 300 kW, 150 kVAR of additional load. A single test was first performed to ensure proper operation. Following that, three sets of three rapid tests were performed, allowing time for the system to recharge between each set of three. The system failed to charge after the first test (this problem was later cor- rected through a modification to the charge control software by the manufacturer). Each of the carry- overs was successful, and at no time were any of the loads dropped. Audible current oscillations occurred as before, primarily while the PQ2000 tracked the utility supply for synchronization. ASD, Resistive and Single- Phase Electronic Loads A 196-kW power supply (which was previously used by PG&E as a mock source of photovoltaic DC gen- eration) served to emulate an electronic adjustable speed drive (ASD) load. The power supply is a 12-pulse, SCR-based AC-DC converter. The DC side of the converter was loaded using a 110-kW inverter (which had been used by PG&E in connection with a molten-carbonate fuel cell demonstration project) connected to the separate MGTF grid bus. The ASD was connected to Breaker 52-15, and the load inverter to Breaker 52-7 as shown in Figure 2-1. In addition to the ASD, a 480/120-V transformer was used to connect various single-phase loads, primarily electronic loads such as computers and printers, etc. The purpose was to verify that sensitive electronic loads are not affected adversely by the transfer or operation of the PQ2000. The voltage sag trip-point tests were repeated because of the potential voltage sensitivity of the electronic loads. | 349.0225 Figure 2-13. Unloaded Motor Starting During Discharge. 2-11 PARTIAL-LOAD TESTS UTILITY TEST RESULTS OF A 2-MEGAWATT, 10-SECOND RESERVE-POWER SYSTEM ASD Outage Tests A series of ASD load combinations were configured to verify the PQ2000 response given utility outages. Table 2-7 below summarizes the 13 outage tests ulti- mately performed from July 24 through 25. A recurring observation during the ASD tests was that one or both of the two power supply “legs” that formed the 12-pulse ASD rectifier would trip off during the transfer to the PQ2000. These trips were caused by the internal ASD voltage relays activating during a test, similar to those reported earlier that occurred on the resistive load banks. As indicated in the table, this happened on five of the 13 outage tests. Figure 2-14 shows an event in which one of the two power supply legs was lost. The load current in the 5227la trace drops significantly as shown. In this case, the power supply trip occurred five to six cycles after the actual load transfer. Figures 2-15 and 2-16 show a successful transfer and reconnect with just the ASD load. With a purely ASD load, 12-pulse harmonics are evident in the load current trace 5216Ia of both figures. The utility cur- rent before transfer in 5216a exhibits far more dra- matic harmonic components. This is caused by the PQ2000 capacitor bank operating in parallel with the ASD. The capacitive current is not included in the load current, which is measured down line of the PQ2000. As is also evident, the voltage harmonics from the PQ2000 are more significant with a purely ASD load. As in the case with the motor load, the ASD loads also experienced oscillations when operating in par- allel with the system. The most significant oscilla- tions took place again when the utility had been re- stored, and the system tracked the utility frequency before reclosing. Slight oscillations also occurred when the transfer was first made. The oscillations are the result of the ASD trying to supply a constant current load to the inverter while being supplied by a varying frequency AC source. The variation in frequency impacts the effective DC current created by the ASD, and oscillations are cre- ated as the ASD control system tries to compensate. A typical oscillation is illustrated in Figure 2-17. Note that the oscillation period is shorter than that of the motor load because it is caused by dueling elec- tronic controllers rather than rotating inertia. 90% Voltage Sag Test A test was performed to verify the system response to a 90% voltage sag while serving the ASD load. An- other test investigated ramping up the ASD load from Table 2-7. Summary of Outage Tests with ASD Loads Test Outage Duration No. Date (sec) Comments 1 7/24 3 ASD only 2 7/124 11 ASD only 3 7/124 - ASD only 4 7/124 - ASD only 5 7/124 3 ASD and 300 kW - Lost power supply No. 2 6 7/24 3 ASD and 300 kW - Lost both PS 7 7/24 3 ASD and 300 kW - Lost PS No. 2 8 7124 3 ASD and 300 kW, 150 kVAR 9 7/25 3 ASD and 300 kW - Lost PS No. 2 10 7/25 3 ASD and 200 kW - Lost PS No. 2 1 7/25 3 ASD and 100 kw 12 7/25 3 ASD and 100 kw 13 7/25 3 ASD and 100 kw 2-12 UTILITY TEST RESULTS OF A 2-MEGAWATT, 10-SECOND RESERVE-POWER SYSTEM PARTIAL-LOAD TESTS 495.1172 v 0.01lus | exons | ea57m08 | A | epeoseer PET ae Len eel OL p LI Ce Meg eee ps EUs | { Mel O.0llus 7 | Figure 2-14. Current Drop upon Loss of One of the Two ASD Power Supplies. Pel Ps ~ C:\GREG\PG of oN prof O as ea a 335.1709 895.0195 Figure 2-15. Transfer with ASD Load Only. Ded tm Oe ee ACL kU ke fF 101S.83 | -toss.727 | 497.6562 621.4944 | 625.2906 TTC een AT ne 3.295 Figure 2-16. Utility Reconnect with ASD Load Only. 2-13 PARTIAL-LOAD TESTS is SCR y PostView 1.3 -- C:\GREG\PG&E\PQ2000\TEST S\WAVEBDOK\ASD\. UTILITY TEST RESULTS OF A 2-MEGAWATT, 10-SECOND RESERVE-POWER SYSTEM 724TST03.1. 596.875 Figure 2-17. Load Current Oscillations During Utility Resynchronization Stage. zero to full power while the PQ2000 system was dis- charging into a 200-kW resistive load. Both tests were successful in that no load was lost, and the PQ2000 handled the ramp-up without any problem. Repetitive Discharge Tests A series of repetitive short-duration discharges were also successfully performed using the ASD. Each outage was approximately one to two seconds long. Electronic Load Outage and Sag Tests Various tests were performed to verify the PQ2000 response to utility outages and sags while the system is serving various electronic load combinations. The 120-V load circuit consists of two PCs with monitors, a laser printer, and a TV-VCR unit. The electronic load tests performed included: e —120-V load circuit and 25-kW resistive load for eight seconds. ¢ — 120-V load circuit and 400-kW resistive load for five seconds. e¢ 120-V load circuit, 200-kW resistive load, 225-kVAR inductive load and ASD for five sec- onds. e — 120-V load circuit, 200-kW resistive load and ASD for five seconds. e Sag with 120-V load circuit, 200-kW resistive load, 225-kVAR inductive load and ASD. e Ten repetitive outages (five with ASD base load and five with 100-kW resistive base). Figure 2-18 shows the transfer to the PQ2000 during the light-load test, consisting of the electronic loads and 25 kW of resistive load. At the time of the trans- fer, one of the two computers was printing to the printers, the other was running the screen saver, and the VCR was playing. None of the electronic loads experienced any problems, and no transients were shown on the computer monitors. The plot does show, however, that the 25-kW resistive load was dropped temporarily at the point of transfer, but came back on less than half a second later. Both of the five-second tests using the ASD resulted in the ASD’s power supply No. 2 tripping off. None of the outage tests caused any problems to the 120-V circuit loads, nor were any problems to the 120-V circuit caused by short duration sags to 90%. The PQ2000 operated correctly on these sags, without impact to the loads. Several attempts were made to create a brief sag con- dition that might affect the PCs if not protected by the PQ2000. However, the only condition that caused a PC reboot was when the supply voltage stayed low (below approximately 455 V) for a length of time. A short-duration drop to below 90% (432 Vac) would not cause a reboot. Therefore, a test could not be performed that would demonstrate this type of prob- lem being solved by the PQ2000. 2-14 UTILITY TEST RESULTS OF A 2-MEGAWATT, 10-SECOND RESERVE-POWER SYSTEM PARTIAL-LOAD TESTS | $22.7148 | sez f 701.2939 : 374.2188 -$22.6084 “2.49608 1316.016 5216Vab = | _-$6.01562 i" -62.496ens T 76 210ms i co oi) eS 2 2 2 2 8 Figure 2-18. Transfer with Electronic Loads and 25-kW Resistor. 2-15 UTILITY TEST RESULTS OF A 2-MEGAWATT, PARTIAL-LOAD TESTS 10-SECOND RESERVE-POWER SYSTEM This page intentionally left blank. 2-16 UTILITY TEST RESULTS OF A 2-MEGAWATT, 10-SECOND RESERVE-POWER SYSTEM FULL-LOAD TESTS 3. Full-Load Tests A series of tests were performed to demonstrate that the PQ2000 met its design rating of 2-MW for 10 secs. The tests included a number of initial charac- terization tests of various discharge lengths. Follow- ing these, a set of repetitive tests was run to assess system reliability. The PQ2000 was physically re- connected in the position shown in Figure 3-1 to ac- commodate the full loading. Ten-Second Tests These tests were designed to demonstrate the full- power and discharge duration of the PQ2000 in re- sponse to a complete loss-of-utility condition. Before these tests, various trial discharges were performed to ensure that the system had been connected in the new position properly and that it could produce the full- load current of 2400 amps (2 MVA at 480 V). Two observations during the initial tests are worth noting. First, the system would not initially respond to full-power outages because the test loads drew currents in one or more phases that marginally ex- ceeded the 2400-amp system rating. In such a situa- tion, the system locked itself out of operation as a self-protective measure. To allow continued testing, the set point was raised to 2500 amps. Second, the system initially had difficulty reconnect- ing to the restored utility at the conclusion of an out- age. The system cycled through multiple reconnects, each separated by an internally set 12-cycle delay. Such a reconnect attempt is illustrated in the half- cycle current notch in Figure 3-2. The behavior was attributed to voltage dips that occurred when the utility transformer first resumed support of the 2-MW load. The dips were interpreted as voltage sags or frequency excursions by the PQ2000, which responded by dropping the utility and serving the load again with the battery. Thus, the system attempted to continue protecting the load from these sags, further confounding the testing. One explanation was that the utility transformer was not sized adequately for the testing (it was rated for 1 MVA continuous duty). The reconnection control was modified to disable the frequency detection logic during reconnect, and this facilitated the testing. Table 3-1 summarizes the results of the ten, 10-sec tests that were performed. The phase currents for each of the tests are shown. The total apparent power from these tests ranged from 1.9 to 2.0 MVA, de- pending on the bus voltage. The voltage was typi- cally low (460-470 Vac) because of the heavy loading of the utility transformer. Figures 3-3 and 3-4 show a successful transfer and reconnect in response to a 2-MVA outage. Short-Duration Tests These tests were performed to characterize the reli- ability of the PQ2000 supplying numerous short- duration (one- to two-second) outages. The results from these tests are summarized in Table 3-2. At no time were loads lost because of a PQ2000 failure, or because of the reconnect attempts described previ- ously. Occasionally a resistive bank tripped on over- voltage during the transfer, as indicated in the table. 3-1 FULL-LOAD TESTS 800A MGTF grid bus ( $2-7 FC PCS 110 KVA UTILITY TEST RESULTS OF A 2-MEGAWATT, 10-SECOND RESERVE-POWER SYSTEM 2MVA rented load 300 300 300 400 600 kW_ekW_kW_skW__kW ;| 5: impedance loop 52-25 ¢ 2-24 52-16 800 A island bus Yamal s2-19( s2-a( s2-14( s2-17( ASD motor 300 400 190 KVA 100 kVA i vvaaluw 300 52-28 wan Alternate parallel loads fia Pa-2000 |" 1 ar ) 7 PQ Node #1 PTs [_ CTs PQ Node #2 52-20 on om CB-3 EO 2000 A )co- smart sub transformer Static switch 2000 KVA 150 kKVAR Figure 3-1. Test Configuration for 2-MVA Load Testing. File Number of Charts GoTo Options Help ee ise PostView 1.3 — I:ADATA\PQ2K\WAVEBOOK\FULL OAL ed ES Figure 3-2. Failed Reconnect Attempt. 3-2 UTILITY TEST RESULTS OF A 2-MEGAWATT, 10-SECOND RESERVE-POWER SYSTEM FULL LOAD TESTS ——————————————————ooooo ooo Table 3-1. Summary of Full-Power, 10-Sec Outage Tests Test Phase A,B,C Load Outage Duration No. Date Current (amps) (sec) Comments 1 8/19 2406, 2346, 2408 9.89 Resistive load 2 8/19 2420, 2357, 2393 9.46 Resistive load 3 8/19 2398, 2369, 2402 9.85 Resistive load 4 8/19 2418, 2402, 2434 10.23 Resistive load 5 8/19 2414, 2391, 2424 10.5 Resistive load 6 8/20 2418, 2379, 2410 9.96 Resistive load 7 8/20 2395, 2354, 2414 10.16 Motor load included 8 8/20 2410, 2381, 2436 10.27 Motor load included 9 8/20 2406, 2367, 2430 10.07 ASD load included 10 8/20 2432, 2387, 2445 10.11 ASD load included 583.0079 v -99.994ms 3344.727 | A -99.994ms 38.7 13ms Figure 3-3. Transfer During 2-MW, 10-sec Outage Test. 3-3 UTILITY TEST RESULTS OF A 2-MEGAWATT, FULL-LOAD TESTS 10-SECOND RESERVE-POWER SYSTEM 62.4072 488.9648 wrath 4b ee ' ' ' ’ ' 1 ' 1 461.1768 FT RSP ren tare torte : 1 1 r 1 776.2208 -797 6856 766.9922 772.8516 4174905 | -$174.805 © 4117.92 a Figure 3-4. Utility Reconnect During 2-MW, 10-sec Outage Test. 3-4 UTILITY TEST RESULTS OF A 2-MEGAWATT, 10-SECOND RESERVE-POWER SYSTEM FULL LOAD TESTS Table 3-2. Summary of Results from 30 Short-Duration Discharges at Full Load Test Phase A,B,C Load Outage Duration No. Date Current (Amps) (sec) Comments 1 8/20 2416, 2391, 2430 1.62 2 8/20 f 1.68 3 8/20 . 1.5 two reconnect attempts 4 8/20 2412, 2363, 2408 1.79 > three reconnect attempts 5 8/20 . 1.39 6 8/20 . 0.68 7 8/20 f 0.95 8 8/20 . 0.83 9 8/20 2424, 2377, 2414 1.39 10 8/20 e 1.53 one reconnect attempt am 8/20 7 1.57 12 8/20 . 1.44 13 8/20 2420, 2375, 2410 0.92 14 8/20 " 0.84 400-kW load bank failed at transfer 15 8/20 Ep 0.96 16 8/20 i 0.95 17 8/20 2406, 2365, 2398 1.06 18 8/20 i 0.82 400-kW load bank failed at transfer 19 8/20 ' 1.06 one reconnect attempt 20 8/20 1.24 OK 21 8/20 2420, 2375, 2410 1.16 one reconnect attempt 22 8/20 ; 1.51 400-kW load bank failed at transfer 23 8/20 ; 1.17 OK 24 8/20 ; 1.20 two reconnect attempts 25 8/21 2430, 2381, 2420 1.17 four reconnect attempts 26 8/21 7 1.28 OK 27 8/21 i 1.25 > two reconnect attempts 28 8/21 2430, 2371, 2408 1.04 OK 29 8/21 7 1.10 one reconnect attempt 30 8/21 i 1.10 OK FULL-LOAD TESTS UTILITY TEST RESULTS OF A 2-MEGAWATT, 10-SECOND RESERVE-POWER SYSTEM This page intentionally left blank. UTILITY TEST RESULTS OF A 2-MEGAWATT, 10-SECOND RESERVE-POWER SYSTEM SYSTEM DESIGN AND OPERATION IMPLICATIONS FROM TEST RESULTS 4. System Design and Operation Implications from Test Results In the course of testing, a number of lessons were learned with respect to the design and application of off-line, reserve-power systems that utilize energy storage. Some of the issues that surfaced led to on- site design modifications of the prototype itself, some led to improved designs for subsequent generations of the PQ2000, and some remain unresolved. The items reported below have been selected based upon their applicability to the technology and appli- cation in general. Design issues considered specific to the PQ2000 are not addressed. System Design Ratings From the outset of the project, the 2-MW, 10-sec performance envelope was specified. The rationale for this rating was in part based on the physical design of the predecessor battery energy storage product that had been developed by the manufacturer. The 10-sec rating was selected in part on the basis of the required startup time for rapid-start diesel gen- erators, such as those used for emergency backup in hospitals and other time-critical applications. In meeting with several potential customers, however, the rating selections were called into question. Some customers found that the 2-MW size exceeded the combined size of their critical-load circuits, and some found that the 2-MW size was not large enough. The manufacturer has developed design concepts for multiple product offerings partly in response to these findings, with ratings of 250 kW, 500 kW, and 1 MW (Meyer, 1998). One system, which the manufacturer fielded shortly after the prototype, was based on the same basic 2-MW design, but included only four of the eight battery modules, giving it a system rating of 1 MW. The system underutilized the container space but met the load requirements of the customer. The 10-sec discharge capability was also called into question. Many diesel generators, particularly gen- erators that are more than a few years old, have longer start times, typically in excess of 15 secs. Some backup power systems are not designed for rapid start at all (rapid-start systems generally circu- late warm oil for immediate starting and loading). These systems would require bridging intervals of 30 to 60 secs. The PQ2000 prototype was designed so that each component was capable of operating at full power for 100 secs (with the exception of the battery, which was designed for 50 secs). Thus, while there is an inverse relationship between discharge duration and battery cycle life, the PQ2000 rating was to some extent ar- bitrary. The 10-sec limit, which was “hard-coded” into the control logic as a precautionary measure, was viewed as a conservative rating appropriate for the first generation unit. Subsequent units with essen- tially the same hardware components were rated for 15 secs, and it is anticipated that the time ratings will be increased further as more field experience is gained. Cost trade-off analyses should be performed by sup- pliers and customers alike to determine when the cost of additional storage capacity exceeds the costs asso- ciated with the purchase and use of rapid-start gen- erators. The physical constraints governing the time rating relate to the heat generated in the power train during discharge. While the actual heat transfer relations are affected by ambient temperature, internal air flow characteristics, and other complicating factors, a rea- sonable first-order approximation may be made by assuming that the overall system rating is determined by the maximum system power rating in MW and the total energy rating in MW-seconds (or “megajoules”). Thus, if the system were rated for 10 secs at 2 MW, it should also be capable of dispatching one MW for about 20 secs without exceeding the power train thermal limits. The final envelope ratings will be determined by the manufacturer. It is worth noting (Meyer, 1998) that UPS manufac- turers generally design and rate equipment with a maximum apparent power at 0.8 power factor. This practice penalizes on a dollar-per-kVA basis those systems that are designed for the same apparent power regardless of power factor (such as the PQ2000). As such, if the PQ2000 could be redesigned with in- creased ratings for the power electronics to provide 4-1 SYSTEM DESIGN AND OPERATION IMPLICATIONS FROM TEST RESULTS UTILITY TEST RESULTS OF A 2-MEGAWATT, 10-SECOND RESERVE-POWER SYSTEM about 2500 kVA at 0.8 power factor (while retaining the 2000 kW rating at unity power factor), the overall improvement in dollar per kVA would far outweigh the incremental system cost on a dollar-per-kW basis. All of the above issues—the preferred power ratings, the treatment of energy versus temporal ratings, and the assumed power factor—remain for the market- place to resolve. Reconnection Logic Utilities often use breakers that automatically reclose several times after an initial trip in case the fault is transient or self-clearing in nature. If these reclosing operations (which generally are timed for a few cy- cles up to a few seconds) fail, the device locks in the open position for safety, requiring manual reset by utility service personnel. Most outages correspond to the duration of the reclosure settings because faults clear more often than not. Faults that do not clear on their own are more serious, requiring utility inspec- tions, repair, and manual device resets. Such faults result in outages of hours or days. Under the typical utility distribution scheme, there- fore, backup power systems with ratings higher than the maximum reclosure settings ensure reliable power for momentary outages, but not extended outages. Customers installing such systems can maximize the effectiveness by coordinating their protection plan with the utility distribution engineering staff. There are occasions, however, when the time required for reserve-power is comparable to the backup system time rating. In a case where the maximum reclosure setting is 2 secs, there are times when 5-sec or 10-sec protective capability in which avert a disruption to end-use loads. Voltage sags originating in the trans- mission system (“brown outs”), for example, can ex- pose loads to out-of-tolerance conditions for many seconds and, depending upon the type of equipment, can cause loss of load and costly downtime. It follows that the design of the reserve-power system should consider outages of any possible duration. The cases shown in Table 4-1 may be generalized, given that the reserve-power system has a finite energy storage capability and that a short (one to two sec- onds) period is required for resyncronizing with the utility. Of these, Cases 1 and 5, momentary and long-term outages, respectively, are considered the most com- mon. Case 1 corresponds to the condition in which the disturbance lasts only a few cycles or a few sec- onds. The reserve-power system is able to carry the load during the disturbance, resynchronize with the utility when it is restored, and transfer the load back to the utility. Case 5 would represent a long-term outage in which case the reserve-power system is forced to shut down, the load is lost, and the system returns to normal once the utility is restored. During the course of testing, it became clear that the system must also be designed to handle the situations Table 4-1. Utility Reconnection Schemes for Energy Storage Systems Description Desirable System Response Case 1 (momentary outage, to resynch. most common) Case 2 Utility is restored without adequate time to resynch. Case 3 Utility is restored immediately after energy storage is depleted, before system shutdown is completed. Case 4 Utility is restored shortly after com- plete shutdown. Case 5 Utility is restored long after com- (long-term outage) plete shutdown. Utility is restored with adequate time System resynchs with utility and reconnects load. Either (1) connect load out of phase to preserve continuity of power to load, or (2) drop load and restart after delay. Depending upon design, may have to force lock- out to complete shut down and start-up se- quences. Outage at load is extended. Voltage may be present on load side because of back-electromotive force from motors winding down. May want time delay or sensing to ensure smooth start up. Start-up sequence initiated when utility is within tolerance. S.:.Ne(jjT0a—€6—6j—jw—0w—a=Rq®«S=EooqOoqoweeeee_e_e_e 4-2 UTILITY TEST RESULTS OF A 2-MEGAWATT, 10-SECOND RESERVE-POWER SYSTEM SYSTEM DESIGN AND OPERATION IMPLICATIONS FROM TEST RESULTS illustrated in Cases 2 through 4. In Case 2, the utility is restored, and the reserve-power system begins to resynchronize with the utility. Depending upon the types of loads, the phase difference at the time of restoration, and other factors, the time to resynchro- nize may be a fraction of a second up to several sec- onds. However, the energy storage is depleted (or the system is otherwise constrained) before the system can fully resynchronize. In this situation, it is not clear whether the system should reconnect the load to the utility before shut- down. Connecting the load would ensure continuous power to the load. However, the transfer would take place out of phase, possibly causing faults or damage to equipment. If an outage were to extend beyond the point at which the energy storage is depleted, the system shuts down and the load is lost. However, the system may require an orderly sequence of events during shutdown (and later start-up), so if the utility is restored during the shutdown sequence (represented by Case 3), it may be desirable to include a lock-out or time-delay de- vice to ensure that the shutdown is completed before start-up begins. In effect, this provision extends the duration of the outage. The final case (Case 4) represents the situation in which the utility is restored and the shutdown is com- plete. However, if unprotected motor loads are present, a back-electromotive force is generated as the motors spin down. If the utility is restored while the motors are still spinning (up to several minutes after the load is lost), it may be problematic to restore power because the load and source are out of fre- quency. Restoring the load may cause excessive torque on the motor shafts and/or electrical damage to the motors. Figure 4-1 shows a motor load that reconnected about 1.5 secs after the PQ2000 stopped its discharge. The utility was restored only about % sec before the reconnect as the motor was slowing down. The utility closed in while out of phase, and the resultant surge tripped the utility breaker and damaged the insulation of the motor’s input cabling. In the figure, the second trace is the newly returned utility source voltage. The load voltage shown in the third trace is the back-electromotive force of the motor load, noticeably under frequency relative to the utility. At the reclose, currents from the utility and load shown are at fault levels. Industrial motors have protective circuitry built in, and it may be sufficient to rely on such circuitry to prevent motor reconnection in a potentially damaging situation. Alternatively, the system could include a site-specific time delay or voltage-sensing circuitry to prevent this from happening. : BOOK\MOTOR\724TST02.10 ~f* File Number of Charts GoTo Options Help 495.2197 425.434¢ | 863.4521 31236255 854.3751 516.408 1862.891 3210547 10.4496 Figure 4-1. Out-of-Phase Reclose on Decaying Motor Load. 4-3 SYSTEM DESIGN AND OPERATION IMPLICATIONS FROM TEST RESULTS Switch Commutation Impacts When the PQ2000 begins to transfer load from the utility to the battery, it immediately ramps up its out- put voltage to 110% of the pre-fault utility voltage. The overshoot is used to commutate (turn off) the SCRs that connect the load to the utility. Throughout the partial-load tests (500 kVA or less), these over- shoots periodically caused certain sensitive control power circuits in the adjustable speed drive (ASD, a 12-pulse SCR rectifier) and the 400-kW resistor bank to trip off. The manufacturer reports that the overshoot has been reduced to 5%, and this should mitigate the problem. In an actual field installation, it would be prudent to coordinate the voltage overshoot with the settings of various critical loads, thereby preventing unnecessary loss of load. Synchronizing with Utility/ Oscillations Audible current oscillations occurred during testing when the PQ2000 was serving either the motor or ASD load. While in no test did the oscillations cause File Number of Charts GoTo Options Help 491.1328 439.7266 UTILITY TEST RESULTS OF A 2-MEGAWATT, 10-SECOND RESERVE-POWER SYSTEM a loss of stability or load, the current magnitude did vary significantly. The test facility constraints pre- vented a more thorough examination with similar loads approaching the 2-MVA rating of the device. The oscillations typically occurred at two times dur- ing an event. The first was when the load transferred from the utility to the battery system. These were observed to dampen within one second. The second, and usually more noticeable occurrence, was when the utility supply was first restored and detected by the system. At this point, the PQ2000 would track the utility phasing to resynchronize, causing the oscillations as shown in Figure 4-2. Such oscillations can, in general, be expected with loads that react dynamically to supply frequency variations. Rotating inertia in motors and the non- linear control of electronics-based drives may actively oppose the frequency control and tracking inherent in off-line UPS systems. The interaction may be quickly damped, or it may set up larger os- cillations. In either case, this is a highly site-specific and load- specific phenomenon. Therefore, customers with this type of load will need to pay careful attention to their interaction with off-line reserve-power systems. BOO OTOR\729 O ~ —{5227RMS 3 490 8691 v 99028 8272RS 329.4078 5227Vab|'#} 405.0393 v 99626 W.7T36 8193517 5216Vab| $j 404.2969 Vv 99626 3.529062 492167 | 5227la 0.976562 A 99626 1462.816 S2i6la_ | ¥ “166.0156 -1866.699 A 99626 99626 Figure 4-2. Motor Current Oscillations. 4-4 UTILITY TEST RESULTS OF A 2-MEGAWATT, 10-SECOND RESERVE-POWER SYSTEM Frequency Detection The initial control specification called for dispatch of the PQ2000 in response to utility-side sags, swells, and outages. However, early loss-of-utility tests with the motor load revealed the necessity to incorporate frequency detection in the load-transfer logic. At the point in which the utility was dropped, the PQ2000 interpreted the back-electromotive force of the motor as in-tolerance utility supply. Therefore, the system did not discharge until the motor output dropped in voltage, at which time the motor frequency was about 58 Hz. The system discharged at 60 Hz, causing abnormal stress on the motor shaft. This observation led to the introduction of frequency detection as part of the load transfer logic (test results teported earlier were taken after this logic was in place). As detection of utility disturbances is integral to any off-line reserve-power system technology, it was concluded that frequency detection ought to be considered in all such designs. Energy Loss Savings An important benefit of “off-line” UPS configura- tions, exemplified by the PQ2000, is the cost savings associated with its reduced loss of energy. Conven- tional “on-line” UPSs (see Appendix A) provide con- tinuity of power by continually rectifying the primary utility power source to a DC bus and then inverting the power to supply the load. These processes, shown in Table 4-2, can result in significant eco- nomic impact. SYSTEM DESIGN AND OPERATION IMPLICATIONS FROM TEST RESULTS Table 4-2. UPS Energy Loss Processes On-line UPS Off-line UPS Rectification Continuous Only during losses post-dispatch charging Battery charge/ Only during Only during discharge dispatch dispatch losses Inversion Continuous Only during losses dispatch The cost of these energy losses depends upon the system ratings, the customer rate schedule, the con- version efficiencies, and the frequency of utility source disturbances. However, the results of a sam- ple calculation are provided below using the assump- tions shown in Table 4-3. The on-line UPS delivers 5,256 MWh to loads over the course of a year. To meet this load, the system incurs inversion losses of 219 MWh and rectification losses of 112 MWh. Losses associated with round- trip battery efficiency are negligible — the total annual energy delivered during outages is only 33 kWh — as are the rectification and inversion losses associated with stored energy. Therefore, the total annual energy loss is 331 MWh. Table 4-4 summarizes loss amounts. Table 4-3. Energy Loss Assumptions UPS Rating Efficiency — Rectification Efficiency — Inversion Cooling coefficient of performance Average cost of power (combined demand and energy charges) Utility disturbances per year Battery DC round-trip efficiency Load factor Service life Inflation Discount rate 1 MW - 10 secs 98% 96% 3.0 $80/MWh 12 (complete discharges) 80% 60% 10 years 3% 8% 45 SYSTEM DESIGN AND OPERATION IMPLICATIONS FROM TEST RESULTS Table 4-4. Sample Energy Loss Calculation for 1-MW UPS Energy Delivered to Loads 5,256 MWh/yr Losses: Inversion 219 MWh/yr Rectification 112 MWh/yr Battery Negligible Cooling 110 MWh/yr Total Loss 441 MWh/yr Total Energy Consumed by 5,697 MWh/yr Customer Se The UPS also incurs an energy penalty in removing this heat from the battery room (excess temperature can result in shutdown of the UPS protection). Power for cooling is about 110 MWh, bringing the total an- nual energy impact from losses and heat removal to 441 MWh, valued at $35,300. The system is assumed to have a 10-year service life, which may be longer than the battery life. For pur- poses of calculating energy losses, the number of battery replacements is not relevant. Taking into ac- count inflation, the value at present of these annual losses is $288,000, or $288/kW. Off-line systems do not incur continuous rectification and inversion losses, and the losses associated with support of dispatch events are negligible as in the on- line case. Both configurations incur parasitic losses associated with control power. Also, the off-line system is assumed to incur static switch cooling losses about equal to the fan power consumption in the UPS, both of which are therefore excluded for purposes of this analysis. The overall energy loss penalty for an on-line system, therefore, is nearly $300/kW. While the market pricing of UPS systems varies considerably depend- ing upon system specifications, the energy loss pen- alty can account for as much as one-third of the total system capital cost. UTILITY TEST RESULTS OF A 2-MEGAWATT, 10-SECOND RESERVE-POWER SYSTEM Energy Management/Power Quality Multimode Operation With energy storage located on the customer side of the meter, it is reasonable to ask whether this energy could be used to provide additional economic benefits by reducing the monthly demand charge and the energy component of the customer’s electric utility bill. Providing both “peak shaving” and _reserve- power capabilities is referred to as “multimode” op- eration. The question of designing a cost-effective multimode energy system revolves around the following issues: ¢ Reserve Capacity. It is anticipated that the power management feature will provide eco- nomic benefits that are secondary in magnitude to reserve-power. By reducing the energy stor- age capacity through the dispatch of on-peak power, the ability of the system to provide Teserve-power is reduced (both the energy stored and the thermal capacity are impacted). A mul- timode system will therefore have to be designed with an additional margin to handle both dispatch types, and the cost of this margin reduces the overall economic justification for multimode capability. ¢ Voltage/Current Sourcing. Most peak-shaving systems operate by sourcing current to the sys- tem, which is supported by the utility. Reserve- power is supplied when the system is discon- nected from the utility and operating as a voltage source. Therefore, these multimode systems will have to be designed with both voltage and cur- Tent source modes of operation, and control logic and circuitry to switch between them. For on-line systems, this is not an issue because the loads are always supplied in voltage-source mode, and peak shaving can be accomplished through reducing the load as seen by the utility. ¢ System Ratings. As peak shaving is supplied over many minutes or hours, the thermal design of the power train is handled as a steady-state system. Thus, the cost advantage gained by designing the PQ2000 in accordance with tran- sient thermal ratings is lost, and the overall sys- tem ratings decline significantly. In the case of the PQ2000, for example, the container rating of 2 MW (short term) would be reduced to 200 — 250 kW (steady-state). 4-6 UTILITY TEST RESULTS OF A 2-MEGAWATT, 10-SECOND RESERVE-POWER SYSTEM SYSTEM DESIGN AND OPERATION IMPLICATIONS FROM TEST RESULTS Reduced steady-state system ratings impact the overall economic justification by reducing the amount of captured demand reduction and peak energy savings. Using the PQ2000 prototype as an example, the customer would size the reserve- power system according to the total peak-power consumption (2 MW), but would only capture demand-reduction savings according to the steady-state rating (250 kW), only one-eighth the total load. Rating incompatibility is not an issue for in-line reserve-power systems because they are already rated for continuous power draw. However, these systems do not take advantage of the tran- sient ratings afforded by off-line systems. Ultimately, the market will determine whether multi- mode systems can be produced at a cost that justifies the dual reserve-power and energy management bene- fits. Energy Storage Technology It is important to note that the primary challenge fac- ing the UPS industry today—the reliability of lead- acid batteries—was never an issue during the course of testing the prototype PQ2000. The batteries per- formed flawlessly throughout the testing period. This is largely believed to be because of the high state-of- charge (SOC) maintained on the batteries, a direct result of the overall design approach. The PQ2000 is designed to handle only momentary outages, typically a few seconds. Even the longest discharge (10 secs) results in a reduction in the SOC by only a few percent. This contrasts dramatically with the market application of conventional UPSs, which handle outages spanning many minutes, reducing SOC by as much as 80 percent, and intro- ducing multiple battery failure modes. The battery selected for the prototype PQ2000 appears to meet all of the application requirements for the short-term discharges of its intended market, and it is expected that the failure mode of this battery will be corrosion of the internal plate grids. This failure mode is related to calendar life (approximately five years) rather than discharge history. 4-7 SYSTEM DESIGN AND OPERATION UTILITY TEST RESULTS OF A 2-MEGAWATT, IMPLICATIONS FROM TEST RESULTS 10-SECOND RESERVE-POWER SYSTEM This page intentionally left blank. 4-8 UTILITY TEST RESULTS OF A 2-MEGAWATT, 10-SECOND RESERVE-POWER SYSTEM CONCLUSIONS AND FURTHER RESEARCH 5. Conclusions and Further Research Diesel Integration A key potential attribute of the PQ2000 design con- cept is the ability to provide “bridging” support between the onset of the utility disturbance and the start-up and load transfer to a diesel generator set. By integrating the PQ2000 with a diesel generator, the technology could provide protection against distur- bances and outages of any duration, and the transfer of supply from the utility to the reserve system would be seamless. Combining the PQ2000 with a diesel generator, how- ever, requires additional development work on con- trols. The current controls have been demonstrated to detect the utility disturbance, transfer load to the sys- tem, disconnect the utility, provide voltage source to the load, resynchronize with the restored utility, and transfer back to the utility. Coordinating the PQ2000 operation with a diesel would require the additional control capability of commanding the diesel to start, bringing the diesel to speed, transferring load to the diesel, and discon- necting the PQ2000. Because both the PQ2000 and the diesel are voltage sources, the transfer to the die- sel would entail either (1) synchronizing the two sources prior to closure, or (2) transitioning the PQ2000 to a current source after connecting the die- sel. A logical follow-on activity would involve a design phase and a demonstration phase. Because the mar- ket would demand compatibility with a number of diesel engine makes, the demonstration might involve operating the system with several different engine generators, obtained through rental sources. Medium-Voltage Interconnection Another potentially important area of further devel- opment concerns the interconnection voltage of the off-line reserve-power system. The PQ2000 proto- type had an interconnection of 480 V (3-phase), which is a common standard for utility service en- trances of commercial electric customers. However, the PQ2000, with a rating of 2 MW, would find application at larger customers (typically classi- fied as “‘industrial”) with higher service voltage rat- ings, such as 4 kV or 12 kV. These “medium- voltage” customers benefit with lower utility tariffs and more practical cable sizing at the service en- trance. It is therefore important to extend off-line reserve- power technology to accommodate these classes by providing a medium-voltage interconnection. Because the power transistors that are used are not rated for voltages of this magnitude, it is necessary to combine multiple, coordinated transistors in a series connection. A “stack” of switching elements could together meet the medium voltage; each element by itself would only carry a portion of the total voltage. A worthwhile follow-on activity would be to develop and demonstrate a medium-voltage off-line system using current PQ2000 technology and static switch technology. Alternative Storage Technologies The batteries used in the PQ2000 prototype proved to be fully capable of meeting the various tests described in this report. Because the system and application do not result in the SOC dropping more than a few percentage points, the batteries are ex- pected to provide service in the field through the end of their calendar design life. Conventional UPSs, which provide extended outage protection on the order of many minutes, however, require batteries that are tolerant of the abuse result- ing from multiple deep discharges. The single-most important technical challenge for the UPS industry is to find a battery that is capable of meeting high stan- dards for reliability, consistency, and energy storage capacity. A number of advanced energy storage technologies, which promise to meet these performance standards and find their place in the market, have been advanced in recent years (see Appendix A). These include the zinc/bromine battery, composite fly- wheels, superconducting magnetic energy storage (SMES), and ultracapacitors. These technologies have largely been developed independently in response to a wide variety of appli- cation requirements. While each holds promise in CONCLUSIONS AND FURTHER RESEARCH UTILITY TEST RESULTS OF A 2-MEGAWATT, 10-SECOND RESERVE-POWER SYSTEM reliability, cost, or energy density, no comprehensive comparisons of them exist on a system-level basis. A technical assessment would encompass a complete technology assessment given current and potential technology. It would address life-cycle costs, energy densities, thermal management requirements, control issues, safety issues, manufacturability, and scalabil- ity. Parallel Generation Large industrial customers have critical loads exceeding the 2-MW rating of the PQ2000. In some cases, it may be possible to isolate separate circuits and protect each with a separate container. In other cases, this may not be feasible, given the load sizes and facility layout. Under these conditions, it will be necessary to use multiple containers to serve a common load (parallel generation). However, the current state of off-line controls technology is not capable of sharing loads, and additional controls development would be re- quired. The development could largely be done through bench testing on a module level (each module would act as a separate generating unit). A full-scale (multi- ple container) demonstration could be conducted at the conclusion of the development. 5-2 UTILITY TEST RESULTS OF A 2-MEGAWATT, 10-SECOND RESERVE-POWER SYSTEM REFERENCES 6. References Ball, G., Utility Distribution System Storage Appli- cations and Experience, May 1996, presented at EPRI Energy Storage Benefits Workshop, New Or- leans, Louisiana. Final Report on the Development of a 2 MW/10 Sec- ond Battery Energy Storage System for Power Dis- turbance Protection, December 11, 1996. DOE Co- Op Agreement, DE-FC04-94AL99852, Omnion Power Engineering Corporation. Myer, H., Omnion Power Engineering Corp., July 27, 1998, personal conversation with B. L. Norris. Norris, B. L., November 1996, PQ2000 Prototype Testing Experience, presented at Energy Storage As- sociation Meeting, Amelia Island, Florida. Swaminathan, S., and Sen, R., July 1998, Review of Power Quality Applications of Energy Storage Sys- tems, SAND98-1513, Sandia National Laboratories. 6-1 REFERENCES UTILITY TEST RESULTS OF A 2-MEGAWATT, 10-SECOND RESERVE-POWER SYSTEM This page intentionally left blank. Outage Mitigation Alternatives A TESTING EXPERIENCE WITH A 2 MW- 10 SECOND RESERVE POWER SYSTEM APPENDIX A Appendix A Outage Mitigation Alternatives Introduction This appendix discusses alternative technologies for outage mitigation applications. Power quality en- compasses a very large range of phenomena and, therefore, a wide array of mitigation technologies. These technologies extend from reducing customer harmonics with a simple passive filter to eliminating service interruptions with a redundant utility feeder and high-power static switch (Swaminathan, 1988). Distribution planners define an outage as the loss or operative failure of a critical component in the power system. An outage may or may not cause an actual interruption of service to a customer, depending on the redundancy of the supply and the nature of the outage. When an interruption does occur, it is de- fined as momentary (less than one minute) or sus- tained (one minute or more). The prototype PQ2000 is an outage mitigation tech- nology that provides backup service for voltage dis- turbances and momentary interruptions of up to ten seconds. If combined with a backup generator, the PQ2000 system could prevent both momentary and sustained interruptions. For purposes of this report, the mitigation technologies described here are those with applications comparable to those of the PQ2000 system; they therefore utilize energy storage of some type or another. In these applications, energy storage is required to meet the combined objectives of: e Providing an alternate, nonutility power supply for several seconds or more, and e Effectively providing instantaneous transfer from the primary source to the back up source. Conventional UPS Technologies On-Line UPS The on-line UPS is the most common and commer- cially successful type available. It is the standard con- figuration for the dominant computer applications market and is also the most widely used in commer- cial and industrial load applications. Figure A-1 illustrates the typical configuration for the on-line UPS. AC power from the utility is rectified to DC, and inverted back again to AC, in a series flow of power to the load. The battery storage is connected to the intermediate DC bus, and its charge is maintained by the rectified utility power. When the utility power fails, the DC-AC inverter serving the load draws energy from the battery. The transfer presents no transient disturbance to the load. Be- cause the load is always fed through the two convert- ers, the on-line UPS imposes a continuous efficiency penalty in the form of converter losses. A bypass switch is provided in case of a failure of the UPS system. The on-line UPSs are generally designed to provide between 5 and 15 minutes of full-rated backup power. Below is a summary of the on-line system’s advantages and disadvantages. Advantages © Most reliable in preventing an interruption: AC power to the load served by same DC bus re- gardless of source; ¢ Provides consistent isolation of load from utility, and potentially superior voltage quality; and e Large existing market, widely established tech- nology. Disadvantages e Continuous energy efficiency penalty; © More components relied upon during normal operation; and e Most expensive design. | UTILITY Figure A-1. On-line UPS configuration. In comparison to the PQ2000, the typical on-line UPS is designed for longer back-up supply, and its power train components must be sized to serve con- APPENDIX A tinuous rated power. The UPS inverter faces the same design considerations as the PQ2000 inverter in terms of reliably, serving a variety of reactive, rotating, and nonlinear loads. However, the on-line UPS inverter has fewer design issues regarding the instantaneous pick-up of various load types from the standby mode of operation. Off-Line UPS The off-line UPS topology is similar to that of the PQ2000. In normal operation, utility power serves the load directly through a static switch. As shown in Figure A-2, the battery and inverter are connected in parallel to the utility and to the other pole of the static switch. When a utility disturbance is detected, the switch transfers the load to the battery-backed inverter. The off-line UPS does not have the com- mercial history its on-line counterpart has, mostly because of its reliance on a fast (static) transfer switch and more complex detection and transfer re- quirements. However, it is gaining popularity be- cause of its inherently high operating efficiency. UTILITY ee Uy i + Figure A-2. Off-line UPS Configuration. ON Advantages e = High efficiency; e Power conditioning system (PCS) and battery power train components sized for shorter dura- tion use; and e Least expensive design. Disadvantages e Finite but extremely brief discontinuity in supply caused by static switch transfer; e No inherent utility isolation; and e Less commercial availability. LOAD TESTING EXPERIENCE WITH A 2 MW- 10 SECOND RESERVE POWER SYSTEM The PQ2000 differs from the typical off-line UPS by providing transient protection against voltage sags and swells, and additional filtering of the utility waveform during normal operation. The standard industry off-line UPS is also designed for longer dis- charges than the PQ2000—up to 15 minutes. There- fore, both the power-train components and the stor- age capacity of the PQ2000 are sized smaller based on short-duration ratings. Line-Interactive UPS A third conventional UPS technology is the line- interactive system shown in Figure A-3. It is essen- tially an off-line system with an additional automatic voltage regulator connected in series to provide the isolation lacking in the off-line system. As a result, it provides protection against voltage sags, surges, and transients that most off-line systems are unable to provide. eee \ if Be Figure A-3. Line-interactive UPS Configuration. Rotating UPS Standard Rotary UPS The rotary UPS is similar to a conventional on-line UPS except that the power rectifier and inverter are rotating machines rather than electronic converters. Figure A-4 shows the configuration for the typical rotary UPS. The utility AC supply feeds an AC mo- tor, which in turn drives an AC generator to provide the supply voltage for the load. A-2 LOAD TESTING EXPERIENCE WITH A 2 MW - 10 SECOND RESERVE POWER SYSTEM UTILITY LOAD DC Motor ~ ~~ AC Motor AC Generator Sle + Figure A-4. Standard Rotary UPS Configuration. Also attached to the AC motor shaft is a DC motor, which is connected to a battery bank. In the event of a utility interruption, the rotating DC motor becomes a generator fed by energy from the battery, and drives the AC motor and generator pair. No contactors or switches are required to transfer the load to and from battery, so power to the load is clean and uninter- rupted. Rotary UPSs have a sustained market serving large critical loads and are widely perceived to have supe- rior reliability to their electronic counterparts. This type of design completely eliminates the recti- fier/charger, inverter, and static bypass switch of conventional UPSs. Advantages e Good isolation of utility and load; clean, low impedance voltage source for load; e Potentially superior interruption reliability over electronic switches and relays; and e Well-established technologies. Disadvantages e Three rotating machines required, each rated for full load; e Efficiency penalty in normal operation from in- line AC motor and generator; and e Expensive. Battery-Free Rotating UPS A number of rotary UPS technologies utilize battery- free designs, in which energy is stored using a fly- wheel or other mechanical element. The most popu- lar is commonly known as a diesel UPS, which con- sists of a synchronous machine, diesel generator, a free-wheel clutch, and an induction coupling with the utility. APPENDIX A In the event of a utility disturbance, kinetic energy stored in the inductively coupled rotors converts the synchronous motor to a generator and starts a diesel generator via the freewheel clutch. The synchronous and diesel generators provide backup for both mo- mentary and sustained outages. Another product uses a hydraulic flywheel with a synchronous generator, the stator of which is con- nected in parallel with the protected load. During a utility interruption, the flywheel causes the synchro- nous motor to generate to the load, providing ride- through capability and, optionally, starting torque for a backup gas or diesel generator. The simplest battery-free design is that of the motor- generator set with a conventional flywheel shown in Figure A-5. In this system, power flows from the utility through the AC motor and generator to the load, as in the case of the rotary UPS. Brief ride- through capability is provided by a spinning flywheel connected on the shaft linking the motor and genera- tor. Of the three, the motor-generator system with the flywheel provides the most isolation between the load and the utility. However, both parallel-operated sys- tems make use of the machine coupling to stabilize voltage and absorb load harmonics. UTILITY H LOAD AC Motor Flywheel AC Generator Figure A-5. Motor-generator Ride-through Con- figuration. Utility-Side Solution: Dual Feed with Static Switch Large industrial or commercial customers with high sensitivity to outages and disturbances may arrange with the utility to have the redundant supply feeder installed. The basic concept of the dual-feed ap- proach is illustrated in Figure A-6. The second feeder originates from a substation or substation bus that is separate from the original primary feed. APPENDIX A TESTING EXPERIENCE WITH A 2 MW- 10 SECOND RESERVE POWER SYSTEM Secondary Supply UTILITY Primary Supply Figure A-6. Dual Utility Feed Configuration with Static Switch. A static switch is used to transfer the customer to the secondary supply feed in the event of a disturbance on the primary feed. For disturbances that originate on the primary distribution supply, this is a highly effective and reliable solution, providing relief from sags, Momentary interruptions and indefinite sus- tained interruptions without energy storage or fuel considerations. However, utilities in the U.S. report that between 10% and 33% of interruptions originate on the trans- mission system, which supplies both the primary and secondary feed. In such instances, the dual-feed system offers no additional protection to the cus- tomer. With no customer-side equipment, this solu- tion also does not provide the electrical isolation that is characteristic of some of the UPS systems de- scribed above. The dual-feed solution is also limited by its expense. Typically only very large customers, or groups of customers such as in an industrial park, can justify the expense (regardless of the financing arrangement between utility and customer) of adding a new feeder. Areas where the load density is relatively high are an exception to this generalization, however, as dis- tances between substations and load are less, and portions of the distribution system may already be networked. Detailed List of PQ2000 Prototype Tests B TESTING EXPERIENCE WITH A 2 MW - 10 SECOND RESERVE POWER SYSTEM APPENDIX B Appendix B Detailed List of PQ2000 Prototype Tests Table B-1. Partial-Load Tests ——— ————————————————————————ooo—————————eOOSSSa>o>— Date Load Duration No. Category 1996 (kVA) (sec) Comments 1 Three outages with R/L load 7/22 500 2 Three times — one event recorded. 2 R/Loutage 7/22 500 10 3 R/L outage 7/22 500 12 4 R/L outage 7/22 500 12 15-second outage 5 R/L outage 7/22 500 12 30-second outage 6 R/Lslow sag 7/22 425 n/a Voltage-response test. Tripped correctly between 430 and 435 Vac. 7 ~ Five R/L fast sags 7/22 425 2 Forty-three repetitive R/L 79 500 2-3 Lost resistive load during transfer on at least 5 tests. Lost resistive load once toward end of a discharge. Insufficient charge on first set of four. Forty-one tests were recorded. 9 Two imbalance R/L sags 7/29 500 2 Voltage trip point between 430 and 435. One test recorded. 10 Four 12-kV cap strike with 7/23 250 <1 Discharged R/L 11. Two 12-kV cap strike w/o 7/23 0 <1 Discharged load 12 Three 12-kV cap strike during 7/23 335 5 Resistive/Inductive load. One test R/L discharge recorded. 13 480-V cap strike during R/L 7/23 335 5 discharge 14 Cap strike (480) 7/23 n/a <1 15 Two outages; cap w/400 kW 7/23 500 10 16 10 outages; cap w/400 kW 7/23 500 2 17 Outage; motor @ 100 kw 7/24 100 3 Oscillations 18 Outage; motor @ 100 kW 7/24 100 8.5 19 Ten outages; motor with R/L 7/29 335 + 2-3 Oscillations motor 20 Outage motor + 300 kW 7/29 300 + 10 Oscillations motor 21 Outage motor only 7/29 motor 10 Oscillations 22 Motor start during discharge 7/29 100 10 Motor not loaded eee OOOOO\ oo APPENDIX B TESTING EXPERIENCE WITH A 2 MW — 10 SECOND RESERVE POWER SYSTEM SSS Table B-1. Partial Load Tests (Continued) Date Load Duration No. Category 1996 (kVA) (sec) Comments 23 Motor no-load to 100 kw 7/29 100 10 Oscillations: lost R-bank for 15 during discharge cycles at transfer 24 Outage motor load only 7/29 motor <1 Immediate open/close test 25 Outage motor + reactor 7/29 iy 1 225 kVAR 26 Outage ASD only 7/24 3 Oscillations 27 Outage ASD only 7/24 8.5 11-second test 28 Outage ASD only 7/24 10 29 Outage ASD only 7/24 12.5 30 Outage ASD & 300 kW 7/24 5 Lost supply No. 2. 31 Outage ASD & 300 kw 7/24 5 Lost supplies No. 1 and No. 2. 32 Outage ASD & 300 kw 7/24 5 Lost supply No. 2. 33 Outage ASD, 300 kw, 7/24 5 Oscillations 150 kVAR 34 Outage ASD & 300 kw 7/25 5 Lost supply No. 2. 35 Outage ASD & 200 kw 7/25 5 Lost supply No. 2. 36 2 outages ASD & 100 kW 7/25 5 37 Outage ASD & 100 kw 7/25 Wa 38 Sag ASD, 250 kW, 225 kVAR 7/25 2 39 Ramp ASD during discharge 7/25 10 w/200 kw 40 Repetitive ASD, 200 kw, 7/25 1 First test tripped supply No. 1. 150 kKVAR 41 Electronic loads 7/26 8 Two computers, printer and TV-VCR 42 Elec + 400 kw 7/26 3 5-second test 43 Elec + 400 kw 7/26 5 Fine 44 2Elec, ASD, 200 kw 7/26 5 Lost ASD supply No. 2 both tests. 45 7 sags w/Elec R/L/ASD 7/26 2 46 Elec, 400 kW, 225 kVAR 7/26 5 Lost ASD supplies No. 1 and No. 2. eee NSS B-2 TESTING EXPERIENCE WITH A 2 MW - 10 SECOND RESERVE POWER SYSTEM APPENDIX B Table B-2. Full-Load Tests Date Load Duration No. Category 1996 (MVA) (sec) Comments Initial tests 8/6 1.9 na Initial tests 8/6 1.5 n/a Voltage notches Initial tests 8/6 1.8 4 1 second outage — Voltage notches 4 Initial tests 8/6 1.9 >5 1 second outage — Voltage notches 5 Initial tests 8/6 1.9 n/a 6 Initial tests 8/6 1.85 2 7 14 multiple diagnostic 8/7-13 1.9 n/a 8 Initial test 8/19 1.9 1 9 Initial test 8/19 1.9 1 10 First 10 seconds 8/19 1.9 10 Lost a resistive bank at transfer. 11. 12.5-second outage 8/19 1.9 12.5 Lost a resistive bank at transfer. 12 14-second outage 8/19 1.9 12.5 13 30-second outage 8/19 1.9 12.5 14 6 repetitive 10-second tests 8/19-20 1.9 10 15 210-second R w/motor 8/20 1.9 10 16 2 10-second R w/ASD 8/20 1.9 10 Lost supplies No. 1 and No. 2 on one test. 17 30 1-second resistive 8/20-21 1.9 1 Occasional voltage notches and lost resistive banks. B-3 TESTING EXPERIENCE WITH A 2 MW - APPENDIX B 10 SECOND RESERVE POWER SYSTEM This page intentionally left blank. List of Tests STRING BEHAVIOR AND DESIGN ANALYSIS OF A 250-kW, GRID-CONNECTED BATTERY ENERGY STORAGE SYSTEM APPENDIX C Appendix C List of Tests The table below shows an overview of the PM250 not shown, but was conducted through April 1994 by testing, beginning with the delivery of the system to subjecting the system to a series of three-hour mock San Ramon, California, and ending with the final load-following cycles and periodic standard baseline short-term characterization tests. Longevity testing is tests. Date Test Title Comments 10/19/93 System arrives 10/23/93 Pre-parallel connection 10/26/93 Pre-parallel connection 2 10/26/93 Start-up and internal protection 11/4/93 Baseline Test No. 2 The first baseline test performed at the Modular Generation Test Facility 11/5/93 Power quality No.1 and §_ BMI measurements; unable to accept signals PF control 100-kHz spectrum analyzer single-phase plots Nicolet storage RFI measurements Audio measurements 11/16/93 Battery replacements Not a test. Batteries 15 and 16 in Module 1 and Battery 6 in Module 3 replaced. 11/17/93 40-minute Block No. 1 190 kW Mod 2 imbalance SOC 32.9% 11/17/93 Harmonics tests BMI snapshots taken during 40-minute block discharge, 250-kW charge, and autocharge. 11/18/93 1-hour Block No. 1 167 kW Mod 6 imbalance SOC offset 11/19/93 2-hour Block No. 1 92 kW Underproducing modules Communications problems Mods 6 and 2 imbalance 30.4% SOC 11/22/93 Module 4 responses Few-second delay of Module 4 during command change from standby to discharge. Confirmed via independent AC current clamp (and audible). 11/24/93 Auxiliary power BMI snapshots taken on the input to aux transformer (CB9); heater, measurements different modes BMI on Module 8, to measure blower on/off, etc. DAS measurements bogus 11/24/93 3-hour Block No. 1 66 kW Utility power blip, subsequent SCADA PC failure Module 6 imbalance STRING BEHAVIOR AND DESIGN ANALYSIS OF A 250-kW, APPENDIX C GRID-CONNECTED BATTERY ENERGY STORAGE SYSTEM Date Test Title Comments 11/29/93 5-hour Block No. 4 44 kw Incomplete Communication failures Smart-sub protection 1/28/94 Qualification Test No. 1 2/3/94 Qualification Test No. 2 2/3/94 Qualification Test No. 3 Changed imbalance limits to +2 and —4 Vdc; Min string, Vde from 510 to 520 Vde 2/14/94 1-hour Block No. 2 155 kw Modules out on low voltage 520 Vdc 25% SOC 2/15/94 2-hour Block No. 2 89 kW Vdc limit returned to 510 Vde 2/16/94 3-hour Block No. 2 65 kW 2/17/94 5-hour Block No. 2 38 kW 2/21/94 40-minute Block No. 2 205 kW 2/22/94 Islanding No. 1 Battery 100 kW, load bank 20-200 kW 108 kW matching tests 2/23/94 Islanding No. 2 Matching 100 kW, varied VARs + 50 kVAR 208 kW matching 0 kKVAR producing vs. consuming Reclose tests 2/23/94 Speed and Stability Response from SCADA and PCS to mode changes DC injection problems 2/24/94 2-hour load follow No. 1 Two humped equivalent to a single 2-hour sine (equivalent) 2/24/94 Module harmonics test Harmonics from 8-1 operating modules planned Unable to run less than four at a time Sensitive to particular module on 2/25/94 3-hour load follow 96-kW peak 2/28/94 2-hour load follow No. 2 134.3-kW peak 3/1/94 4-hour load follow 75.5-kW peak 3/2/94 5-hour load follow No. 1 62.1-kW peak 3/7/94 8-hour load follow No. 1 Cancelled midstream for bad SOC calculations 3/7/94 5-hour load follow No. 2 62.1-kW Ran with corrected SOC calculation Immediately followed the failed 8-hour attempt 3/8/94 Opportunity charge No.1 2-hour load follow discharge to 25% 2-hour sine charge 2-hour load follow Shutdown early on SOC 3/14/94 8-hour load follow No. 2 38-kW peak 3/15/94 Opportunity Charge Different charge/discharge thresholds No. 2 2-hour load follow? Deep charge load follow/problems accepting >265 kW 1.5-hour discharge C-2 STRING BEHAVIOR AND DESIGN ANALYSIS OF A 250-kW, GRID-CONNECTED BATTERY ENERGY STORAGE SYSTEM APPENDIX C Date Test Title Comments 3/15/94 Container power tests Discrepancies between requested, commanded, DAS, and PQ node 3/21/94 250-kW block discharge measurements recorded. Approx. 26-minute test to 25% SOC Modules out on low Vdc (voltage). C-3 STRING BEHAVIOR AND DESIGN ANALYSIS OF A 250-kW, APPENDIX C GRID-CONNECTED BATTERY ENERGY STORAGE SYSTEM This page intentionally left blank. C4 Bob Weaver 777 Wildwood Lane Palo Alto, CA 94303 Robert W. Fenn 6335 Coleridge Road Painesville, OH 44077 Hans Weinerich ABB Power T&D Co., Inc. 1460 Livingston Ave. P.O. Box 6005 North Brunswick, NJ 08902-6005 Robert Wills Advanced Energy Systems Riverview Mill P.O. Box 262 Wilton, NH 03086 Percy Frisbey Alaska State Div. of Energy 333 West Fourth Ave. Suite 220 Anchorage, AK 99501-2341 Distribution Eric Rudd 35 Harmon Ave Painesville, OH 44077 Per Danfors ABB Power T&D Co., Inc. 16250 West Glendale Drive New Berlin, WI 53151 Jim Balthazar Active Power 11525 Stonehollow Dr. Suite 255 Austin, TX 78758 B. Tiedeman Alaska State Div. of Energy 333 West Fourth Ave. Suite 220 Anchorage, AK 99501-2341 P. Crump Alaska State Div. of Energy 333 West Fourth Ave. Suite 220 Anchorage, AK 99501-2341 Michael L. Gravely American Superconductor Corp. 8371 Bunchberry Court Citrus Heights, CA 95610 Christopher G. Strug American Superconductor Corp. Two Technology Drive Westborough, MA 01581 Tim Ball Applied Power Corporation Solar Engineering 1210 Homann Drive SE Lacey, WA 98503 Christian St-Pierre ARGO-TECH Productions, Inc. Subsidiary of Hydro-Quebec 1580 de Coulomb Boucherville, QC J4B 7Z7 CANADA Ira Bloom Argonne National Laboratories 9700 South Cass Avenue CTD, Bldg. 205 Argonne, IL 60439-4837 C. Shih American Elec. Pwr. Serv. Corp. 1 Riverside Plaza Columbus, OH 43215 Meera Kohler Anchorage Municipal Light & Pwr 1200 East 1st Avenue Anchorage, AK 99501 Ralph M. Nigro Applied Energy Group, Inc. 46 Winding Hill Drive Hockessin, DE 19707 Gary Henriksen Argonne National Laboratories 9700 South Cass Avenue CTD, Bldg. 205 Argonne, IL 60439 Herb Hayden Arizona Public Service 400 North Fifth Street P.O. Box 53999, MS8931 Phoenix, AZ 85072-3999 Ray Hobbs Arizona Public Service 400 North Fifth Street P.O. Box 5399, MS8931 Phoenix, AZ 85072-3999 Edward C. Kern Ascension Technology, Inc. P.O. Box 6314 Lincoln, MA 01773-6314 Rick Lawrence AVO International P.O. Box 9007 Valley Forge, PA 19485-1007 Richard L. 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Kulkarni California Energy Comission Research & Dev. Office 1516 9th Street, MS43 Sacramento, CA 95814-5512 Gerald W. Braun BP Solarex 630 Solarex Court Frederick, MD 21703 Dr. Sudhan S. Misra C&D Charter Pwr. Systems, Inc. Washington & Cherry Sts. Conshohocken, PA 19428 Larry S. Meisner C&D Powercom 1400 Union Meeting Road P.O. Box 3053 Blue Bell, PA 19422-0858 J. Holmes California State Air Resc. Board Research Division P.O. Box 2815 Sacramento, CA 95812 Rod Boucher Calpine Corporation 50 W. San Fernando Suite 550 San Jose, CA 95113 Tom Lovas Chugach Elec. Association, Inc. 5601 Minnesota Dr. P.O. Box 196300 Anchorage, AK 99519-6300 M. Lebow Consolidated Edison 4 Irving Place New York, NY 10003 R. Stack Corn Belt Electric Cooperative P.O. Box 816 Bloomington, IL 61702 J. Michael Hinga Delphi Energy & Engine Management Systems P.O. Box 502650 Indianapolis, IN 46250 Bob Rider Delphi Energy & Engine Management Systems P.O. Box 502650 Indianapolis, IN 46250 John Cooley Chugach Elec. Association, Inc. P.O. Box 196300 Anchorage, AK 99519-6300 N. Tai Consolidated Edison 4 Irving Place New York, NY 10003 R. B. Sloan Crescent EMC P.O. Box 1831 Statesville, NC 28687 Bob Galyen Delphi Energy. & Engine Management Systems P.O. Box 502650 Indianapolis, IN 46250 Joseph J. Ianucci Distributed Utility Associates 1062 Concannon Blvd. Livermore, CA 94550 Alan Collinson EA Technology Limited Chester CH1 6ES Capenhurst, England UNITD KINGDOM M. Stanton East Penn Manufact. Co., Inc. Deka Road Lyon Station, PA 19536 Steve Eckroad Elec. Pwr. Research Institute P.O. Box 10412 Palo Alto, CA 94303-0813 Steve Chapel Elec. Pwr. Research Institute P.O. Box 10412 Palo Alto, CA 94303-0813 Dave Feder Electrochemical Energy Storage Systems, Inc. 35 Ridgedale Avenue Madison, NJ 07940 Jim DeGruson Eagle-Picher Industries. Inc. C & Porter Street Joplin, MO 64802 Daniel R. Bruck ECG Consulting Group, Inc. 55-6 Woodlake Road Albany, NY 12203 Robert Schainker Elec. Pwr. Research Institute P.O. Box 10412 Palo Alto, CA 94303-0813 Phillip C. Symons Electrochemical Engineering Consultants, Inc. 1295 Kelly Park Circle Morgan Hill, CA 95037 Michael Dodge Electrosource P.O. Box 7115 Loveland, CO 80537 Harald Haegermark Elforsk-Swedish Elec Utilities R&D Co Elforsk AB Stockholm, S-101 53 Sweden Jennifer Schilling Energetics 501 School Street SW Suite 500 Washington, DC 20024 Paula A. Taylor Energetics 7164 Gateway Drive Columbia, MD 21046 Howard Lowitt Energetics 7164 Gateway Drive Columbia, MD 21046 Laura Johnson Energetics, Inc. 7164 Gateway Drive Columbia, MD 21046 Chuck Whitaker Endecon 2500 Old Crow Canyon Road Suite 220 San Ramon, CA 94583 Phil DiPietro Energetics 501 School Street SW Suite 500 Washington, DC 20024 Mindi J. Farber De Anda Energetics 501 School Street SW Suite 500 Washington, DC 20024 Rich Scheer Energetics 501 School Street SW Suite 500 Washington, DC 20024 Greg J. Ball Energy & Env. Economics, Inc. 353 Sacramento Street Suite 1540 San Francisco, CA 94111 Amber Gray-Fenner Energy Communications Consulting 7204 Marigot Rd. NW Albuquerque, NM 87120 Robert Duval EnerVision P,O, Box 450789 Atlanta, GA 31145-0789 Erik Hennig EUS GmbH MunscheidstraBe 14 Gelsenkirchen, 45886 Germany J. Mills Firing Circuits, Inc. P.O. Box 2007 Norwalk, CT 06852-2007 Steven J. Durand Florida Solar Energy Center 1679 Clearlake Road Cocoa, FL 32922-5703 Dale Butler EnerTec Pty. Ltd. 349 Coronation Drive PO Box 1139, Milton BC Old 4044 Auchenflower, Queensland, 4066 AUSTRALIA David H. DaCosta Ergenics, Inc. 247 Margaret King Avenue Ringwood, NJ 07456 John Breckenridge Exide Electronics 8609 Six Forks Road Raleigh, NC 27615 James P. Dunlop Florida Solar Energy Center 1679 Clearlake Road Cocoa, FL 32922-5703 Steven Kraft Frost & Sullivan 2525 Charleston Road Mountain View, CA 94043 Dave Coleman Frost & Sullivan 2525 Charleston Road Mountain View, CA 94043 Nick Miller General Electric Company 1 River Road Building 2, Room 605 Schenectady, NY 12345 Gerry Woolf Gerry Woolf Associates 17 Westmeston Avenue Rottingdean, East Sussex, BN2 8AL UNITED KINGDOM George Hunt GNB Tech. Ind. Battery Co. Woodlake Corporate Park 829 Parkview Blvd. Lombard, IL 60148-3249 Sanjay Deshpande' GNB Technologies Woodlake Corporate Park 829 Parkview Blvd. Lombard, IL 60148-3249 Bob Zrebiec GE Industrial & Pwr. Services 640 Freedom Business Center King of Prussia, PA 19046 Declan Daly General Electric Drive Systems 1501 Roanoke Blvd. Salem, VA 24153 Anthony B. LaConti Giner, Inc. 14 Spring Street Waltham, MA 02451-4497 Joe Szymborski GNB Tech. Ind. Battery Co. Woodlake Corporate Park 829 Parkview Blvd. Lombard, IL 60148-3249 J. Boehm GNB Tech. Ind. Battery Co. Woodlake Corporate Park 829 Parkview Blvd. Lombard, IL 60148-3249 Steven Haagensen Golden Valley Elec. Assoc., Inc. 758 Illinois Street P.O. Box 71249 Fairbanks, AK 99701 Clyde Nagata Hawaii Electric Light Co. P.O. Box 1027 Hilo, HI 96720 Carl Parker ILZRO 2525 Meridian Parkway P.O. Box 12036 Research Triangle Park, NC 27709 Jerome F. Cole ILZRO 2525 Meridian Parkway PO Box 12036 Research Triangle Park, NC 27709 Ken Belfer Innovative Power Sources 1419 Via Jon Jose Road Alamo, CA 94507 Ben Norris Gridwise Engineering Company 121 Starlight Place Danville, CA 94526 George H. Nolin HL&P Energy Services P.O. Box 4300 Houston, TX 77210-4300 Patrick Moseley ILZRO 2525 Meridian Parkway P.O. Box 12036 Research Triangle Park, NC 27709 Ron Myers Imperial Oil Research Centre 3535 Research Road NW Room 2E-123 Calgary, Alberta, T2L 2K8 CANADA Albert R. Landgrebe Int'l Electrochemical Sys & Technology B14 Sussex Lane Long Neck, DE 19966 David Warar Intercon Limited 6865 Lincoln Avenue Lincolnwood, IL 60646 John Neal Internation! Business & Tech. Services, Inc. 9220 Tayloes Neck Road Nanjemoy, MD 20662 Elton Cairns Lawrence Berkeley Nat'l Lab University of California One Cyclotron Road Berkeley, CA 94720 Kim Kinoshita Lawrence Berkeley Nat'l Lab University of California One Cyclotron Road Berkeley, CA 94720 Susan M. Schoenung Longitude 122 West, Inc. 1010 Doyle Street Suite 10 Menlo Park, CA 94025 A. Kamal Kalafala Intermagnetics General Corp. 450 Old Niskayuna Road P.O. Box 461 Latham, NY 12110-0461 Gerard H. C. M. Thijssen KEMA T&D Power Utrechtseweg 310 P.O. Box 9035 ET, Emhem, 6800 The Netherlands Frank McLarnon Lawrence Berkeley National Lab University of California One Cyclotron Road Berkeley, CA 94720 J. Ray Smith Lawrence Livermore Nat'l Lab University of California P.O. Box 808, L-641 Livermore, CA 94551 Joseph Morabito Lucent Technologies, Inc. 600 Mountain View Ave. P.O. Box 636 Murray Hill, NJ 07974-0636 Cecilia Y. Mak Lucent Technologies 3000 Skyline Drive Room 855 Mesquite, TX 75149-1802 Dutch Achenbach Metlakatla Power & Light P.O. Box 359 3.5 Mile Airport Road Metlakatla, AK 99926 Dr. Christine E. Platt Nat'l Institute of Standards & Tech. Room A225 Administration Bldg. Gaithersburg, MD 20899 Holly Thomas Nat'l Renewable Energy Lab 1617 Cole Boulevard Golden, CO 80401-3393 Jim Green Nat'l Renewable Energy Lab 1617 Cole Boulevard Golden, CO 80401-3393 Stephen R. Connors Massachusetts Inst of Tech The Energy Laboratory Rm E40-465 Cambridge, MA 02139-4307 D. Nowack Micron Corporation 158 Orchard Lane Winchester, TN 37398 Byron Stafford Nat'l Renewable Energy Lab 1617 Cole Boulevard Golden, CO 80401-3393 Richard DeBlasio Nat'l Renewable Energy Lab 1617 Cole Boulevard Golden, CO 80401-3393 Larry Flowers Nat'l Renewable Energy Lab 1617 Cole Boulevard Golden, CO 80401-3393 Susan Hock Nat'l Renewable Energy Lab 1617 Cole Boulevard Golden, CO 80401-3393 Steven P. Lindenberg National Rural Elec Cooperative Assoc. 4301 Wilson Blvd. SSER9-207 Arlington, VA 22203-1860 Andrew L. Rosenthal New Mexico State University Southwest Tech. Dev. Institute Box 30001/Dept. 3SOL Las Cruces, NM 88003-8001 Gary G. Karn Northern States Power Co. 1518 Chestnut Avenue North Minneapolis, MN 55403 Jack Brown NPA Technology Two University Place Suite 700 Durham, NC 27707 Anthony Price National Power PLC Harwell Int'l Business Ctr. Harwell, Didcot, OX11 0QA UNITED KINGDOM Bill Brooks NC Solar Center Corner of Gorman & Western Box 7401 NCSU Raleigh, NC 27695-740 Bart Chezar New York Power Authority 1633 Broadway New York, NY 10019 Denise Zurn Northern States Power Co. 414 Nicollet Mall Minneapolis, MN 55401 John Stoval Oak Ridge National Laboratory P.O. Box 2008 Bldg. 3147, MS-6070 Oak Ridge, TN 37831-6070 Robert Hawsey Oak Ridge National Laboratory P.O. Box 2008 Bldg. 3025, MS-6040 Oak Ridge, TN 37831-6040 Brendan Kirby Oak Ridge National Laboratory P.O. Box 2008 Bldg. 3147, MS-6070 Oak Ridge, TN 37831-6070 Douglas R. Danley Orion Energy Corporation 10087 Tyler Place #5 Ijamsville, MD 21754 Daryl Brown Pacific Northwest Nat'l Lab Battelle Blvd. MS K8-07 P.O. Box 999 Richland, WA 99352 Brad Johnson PEPCO 1900 Pennsylvania NW Washington, DC 20068 James VanCoevering Oak Ridge National Laboratory P.O. Box 2008 Bldg. 3147, MS-6070 Oak Ridge, TN 37831-6070 Hans Meyer Omnion Pwr. Engineering Corp. 2010 Energy Drive P.O. Box 879 East Troy, WI 53120 John DeStreese Pacific Northwest Nat'l Lab Battelle Blvd. P.O. Box 999, K5-02 Richland, WA 99352 Thomas H. Schucan Paul Scherrer Institut CH - 5232 Villigen PSI Switzerland Stan Sostrom POWER Engineers, Inc. P.O. Box 777 3870 US Hwy 16 Newcastle, WY 82701 P. Prabhakara Power Technologies, Inc. 1482 Erie Blvd. P.O. Box 1058 Schenectady, NY 12301 Reznor I. Orr PowerCell Corporation 99 South Bedford Street Suite 2 Burlington, MA 01803 Roger Flynn Public Service Co. of New Mexico Alvarado Square MS-2838 Albuquerque, NM 87158 Norman Lindsay Queensland Department of Mines and Energy G.P.O. Box 194 Brisbane, 4001 QLD. AUSTRALIA Al Randall Raytheon Eng. & Constructors 700 South Ash Street P.O. Box 5888 Denver, CO 80217 Rick Winter Powercell Corporation 99 South Bedford Street Suite 2 Burlington, MA 01803 Jerry Neal Public Service Co. of New Mexico Alvarado Square MS-BA52 Albuquerque, NM 87158 Wenceslao Torres Puerto Rico Elec. Pwr. Authority P.O. Box 364267 San Juan, PR 00936-4267 J. Thompson R&D Associates 2100 Washington Blvd. Arlington, VA 22204-5706 K. Ferris RMS Company 135 Post Office Rd. South Salem, NY 10590-1106 George V. Fantozzi S&C Electric Company 6601 North Ridge Blvd. Chicago, IL 60626-3997 Guy Chagnon SAFT Research & Dev. Ctr. 107 Beaver Court Cockeysville, MD 21030 G. E. "Emie" Palomino Salt River Project P.O. Box 52025 MS PAB 357 Phoenix, AZ 85072-2025 Robert Reeves Sentech, Inc. 9 Eaton Road Troy, NY 12180 Rajat K. Sen Sentech, Inc. 4733 Bethesda Avenue Suite 608 Bethesda, MD 20814 Jim McDowall SAFT America, Inc. 3 Powdered Metal Drive North Haven, CT 06473 Michael C. Saft SAFT Research & Dev. Ctr. 107 Beaver Court Cockeysville, MD 21030 Dr. Charles Feinstein Santa Clara University Dept. of Dec. & Info. Sciences Leavey School of Bus. & Admin. Santa Clara, CA 95053 Kurt Klunder Sentech, Inc. 4733 Bethesda Avenue Suite 608 Bethesda, MD 20814 Nicole Miller Sentech, Inc. 4733 Bethesda Avenue Suite 608 Bethesda, MD 20814 Clay Aldrich Siemens Solar 4650 Adohr Lane P.O. Box 6032 Camarillo, CA 93011 Scott Sklar Solar Energy Ind. Assoc. (SEIA) 1111 North 19th St Suite 2604th Floor Arlington, VA 22209 Bruce R. Rauhe, Jr. Southern Company Services, Inc. 600 North 18th Street P.O. Box 2625 Birmingham, AL 35202-2625 Richard N. Schweinberg Southern California Edison 6070 N. Irwindale Avenue Suite I Irwindale, CA 91702 George Zink Stored Energy Engineering 7601 E. 88th Place Indianapolis, IN 46256 Deepak Divan Soft Switching Technologies 2224 Evergreen Road Suite 6 Middleton, WI 53562 Naum Pinsky Southern California Edison 2244 Walnut Grove Ave. P.O. Box 800, Room 418 Rosemead, CA 91770 K. Vakhshoorzadeh Southern Company Services, Inc. 600 North 18th Street P.O. Box 2625 Birmingham, AL 35202-2625 C. Seitz SRI International 333 Ravenswood Avenue Menlo Park, CA 94025 Bob Bish Stored Energy Engineering 7601 E. 88th Place Indianapolis, IN 46256 Jon Hurwitch Switch Technologies 4733 Bethesda Avenue Suite 608 Bethesda, MD 20814 Harold Gotschall Technology Insights 6540 Lusk Blvd. Suite C-102 San Diego, CA 92121 Haukur Asgeirsson The Detroit Edison Company 2000 2nd Ave. 435 SB Detroit, MI 48226-1279 Michael Orians The Solar Connection P.O. Box 1138 Morro Bay, CA 93443 Bill Roppenecker Trace Engineering Division 5916 195th Northeast Arlington, WA 98223 Terri Hensley Tampa Electric Company P.O. Box 111 Tampa, FL 33601-0111 Thomas J. Jenkin The Brattle Group 44 Brattle Street Cambridge, MA 02138-3736 Charles E. Bakis The Pennsylvania State University 227 Hammond Building University Park, PA 16802 Tom Anyos The Technology Group, Inc. 63 Linden Avenue Atherton, CA 94027-2161 Bill Erdman Trace Technologies 161G South Vasco Road P.O. Box 5049 Livermore, CA 94550 Michael Behnke Trace Technologies 161G South Vasco Road P.O. Box 5049 Livermore, CA 94550 Jim Drizos Trojan Battery Company 12380 Clark Street Santa Fe Springs, CA 90670 Paul C. Klimas U.S. Agency for Intn'l Development Center for Environment Washington, DC 20523-3800 Dan T. Ton U.S. Department of Energy 1000 Independence Ave. SW EE-11 FORSTL Washington, DC 20585 Gary A. Buckingham U.S. Department of Energy Albuquerque Operations Office P.O. Box 5400 Albuquerque, NM 87185 Donald A. Bender Trinity Flywheel Power 6724D Preston Avenue Livermore, CA 94550 James Fangue TU Electric R&D Programs P.O. Box 970 Fort Worth, TX 76101 Jim Daley U.S. Department of Energy 1000 Independence Ave. SW EE-12 FORSTL Washington, DC 20585 James E. Rannels U.S. Department of Energy 1000 Independence Ave. SW EE-11 FORSTL Washington, DC 20585-0121 Mark B. Ginsberg U.S. Department of Energy 1000 Independence Ave. SW EE-90 FORSTL 5E-052 Washington, DC 20585 Alex O. Bulawka U.S. Department of Energy 1000 Independence Ave. SW EE-11 FORSTL Washington, DC 20585 J. A. Mazer U.S. Department of Energy 1000 Independence Ave. SW EE-1] FORSTL Washington, DC 20585 Richard J. King U.S. Department of Energy 1000 Independence Ave. SW EE-11 FORSTL, 5H-095 Washington, DC 20585 Kenneth L. Heitner U.S. Department of Energy 1000 Independence Ave. SW EE-32 FORSTL, Rm. 5G-030 Washington, DC 20585 Neal Rossmeissl U.S. Department of Energy 1000 Independence Ave. SW EE-13 FORSTL Washington, DC 20585 Tien Q. Duong U.S. Department of Energy 1000 Independence Ave. SW EE-32 FORSTL, Rm. 5G-030 Washington, DC 20585 J. P. Archibald U.S. Department of Energy 1000 Independence Ave. SW EE-90 FORSTL Washington, DC 20585 Russ Eaton U.S. Department of Energy Golden Field Office 1617 Cole Blvd., Bldg. 17 Golden, CO 80401 Bob Brewer U.S. Department of Energy 1000 Independence Ave. SW EE-10 FORSTL Washington, DC 20585 Allan Jelacic U.S. Department of Energy 1000 Independence Ave. SW EE-12 FORSTL Washington, DC 20585 R. Eynon U.S. Department of Energy 1000 Independence Ave. SW EI-821 FORSTL Washington, DC 20585 Philip N. Overholt U.S. Department of Energy 1000 Independence Ave. SW EE-11 FORSTL Washington, DC 20585-0121 Pandit G. Patil U.S. Department of Energy 1000 Independence Ave. SW EE-32 FORSTL Washington, DC 20585 Jack Cadogan U.S. Department of Energy 1000 Independence Ave. SW EE-11 FORSTL Washington, DC 20585 Paul Maupin U.S. Department of Energy 19901 Germantown Rd ER-14 E-422 Germantown, MD 20874-1290 Alex G. Crawley U.S. Department of Energy 1000 Independence Ave. SW EE-90 FORSTL Washington, DC 20585 W. Butler U.S. Department of Energy 1000 Independence Ave. SW PA-3 FORSTL Washington, DC 20585 Allan Hoffman U.S. Department of Energy 1000 Independence Ave. SW EE-10 FORSTL Washington, DC 20585 Joe Galdo U.S. Department of Energy 1000 Independence Ave. SW EE-10 FORSTL Washington, DC 20585 Dr. Gerald P. Ceasar U.S. Department of Commerce NIST/ATP Bldg 101, Room 623 Gaithersburg, MD 20899 Dr. Imre Gyuk U.S. Department of Energy 1000 Independence Ave. SW EE-14 FORSTL Washington, DC 20585 Wayne Taylor U.S. Navy Code 83B000D, NAWS China Lake, CA 93555 John Herbst University of Texas at Austin J.J. Pickel Research Campus Mail Code R7000 Austin, TX 78712 Mariesa Crow University of Missouri-Rolla 233 EECH Rolla, MO 65409-0040 Steve Hester Utility Photo Voltaic Group 1800 M Street NW Washington, DC 20036-5802 Steve Bitterly U.S. Flywheel Systems 1125-A Business Center Circle Newbury Park, CA 91320 Edward Beardsworth UFTO 951 Lincoln Avenue Palo Alto, CA 94301-3041 Max Anderson University of Missouri - Rolla 112 Electrical Eng. Bldg. Rolla, MO 65401-0249 G. Alan Palin Urenco (Capenhurst) Ltd. Capenhurst, Chester, CH] 6ER UNITED KINGDOM Mike Stern - Utility Power Group 21250 Califa Street Suite 111 Woodland Hills, CA 91367-5029 Rick Ubaldi VEDCO Energy 12 Agatha Lane Wayne, NJ 07470 Alex Q. Huang Virginia Polytechnic Instit. & State Uni Virginia Power Electronics Center 672 Whittemore Hall Blacksburg, VA 24061 Gerald J. Keane Westinghouse Elec. Corp. Energy Management Division 4400 Alafaya Trail Orlando, FL 32826-2399 Tom Matty Westinghouse P.O. Box 17230 Maryland, MD 21023 Nicholas J. Magnani Yuasa, Inc. 2366 Bernville Road P.O. Box 14145 Reading, PA 19612-4145 Gary Verno Virginia Power Innsbrook Technical Center 5000 Dominion Blvd. Glen Ellen, VA 23233 Randy Bevin Walt Disney World Design and Eng'g P.O. Box 10,000 Lake Buena Vista, FL 32830-1000 Howard Saunders Westinghouse STC 1310 Beulah Road Pittsburgh, PA 15235 Frank Tarantino Yuasa, Inc. 2366 Bernville Road P.O. Box 14145 Reading, PA 19612-4145 Gene Cook Yuasa-Exide, Inc. 262 Valley Road Warrington, PA 18976 R. Kristiansen Yuasa-Exide, Inc. 35 Loch Lomond Lane Middleton, NY 10941-1421 Robert J. Parry ZBB Technologies 11607 West Dearbourn Ave. Wauwatosa, WI 53226-3961 MS-0612/04912 MS-0212/10251 MS-0340/01832 MS-0457/02000 MS-0537/023 14 MS-0953/02500 MS-0953/02501 MS-0613/02521 MS-0613/02521 MS-0613/02521 MS-0614/02522 MS-0614/02523 MS-0613/02525 MS-0613/02525 MS-0613/02525 MS-0613/02525 MS-0613/02525 MS-0613/02525 MS-0899/04916 MS-0741/06200 MS-0704/06201 MS-0708/06214 MS-0753/06218 MS-0753/06218 MS-0753/06218 MS-0753/06218 MS-0753/06218 MS-0455/06201 MS-9403/08723 MS-9018/08940-2 MS-1193/09531 Henry W. Zaininger Zaininger Engineering Co., Inc. 9959 Granite Crest Court Granite Bay, CA 95746 Phillip A. Eidler ZBB Technologies, Inc. 11607 West Dearbourn Ave. Wauwatosa, WI 53226-3961 Review & Approval For DOE/OSTI (1) Julie A. McBride Jeff W. Braithwaite Gary N. Beeler Stanley Atcitty William E. Alzheimer J. Thomas Cutchen Daniel H. Doughty Terry M. Unkelhaeuser Rudolph G. Jungst Dennis E. Mitchell Robert W. Bickes, Jr. Garth P. Corey Gustavo P. Rodriguez James T. Crow Nancy H. Clark Paul C. Butler (10) John D. Boyes Technical Library (2) Samuel G. Varnado Abbas A. Akhil Henry M. Dodd Christopher P. Cameron Russell H. Bonn Thomas D. Hund John W. Stevens Ward I. Bower Marjorie L. Tatro James C. F. Wang Central Technical Files Dean C. Rovang