ML17291B293
| ML17291B293 | |
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|---|---|
| Site: | Columbia  |
| Issue date: | 12/31/1995 |
| From: | Mccluskey R, Oliver J, Weiss H BECHTEL CORP., GENERAL ELECTRIC CO., SOUTHERN CALIFORNIA EDISON CO. |
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| NUDOCS 9604150092 | |
| Download: ML17291B293 (30) | |
Text
cs 92 WM 059-6 EC AD3USTABLE-SPEED DRZVE RETROFZT FOR ORMOND BEACH FD FANS Z. A. Oliver H. W. We iss Bechcel Corporation General Electric Co.
R. K. McCluskey Mo Z S amoco Southern California Edison Co., Electric Paver Research Znstitute hat ~
California Edison's
- The 750 boiler MW on Oxmond Beach Southern Unit 2 paver savings, measured haxmanics at utility bus and at the motor, effect of THD reduction was extensively modified ta reduce minimum by using an input harmonic filter, and load f am 250 MW to 36 MW. With the unit operating experience ta date. Fan inlet vanes operating at minimum laad frequently at night, have been removed, and no ASD bypass was it became economically attractive to instaLL provided.
ad)ustable-speed drives (ASDs) on each of the 6250 hp Forced Draft Fan Motors.
The ASD technology that was used is a fourth The technology for the ad)ustable-speed generation current-souxce, GTO-PWM inverter drives (ASDs) used for the Oxmand Beach that is used in a configuration foscered by a Generating Station Unit 2 Forced Draft Fans series of f've ASD field tests conducted for resulted f om the experience gained in five EPRZ by Bechtel in the period fram 1984 Co FPRI-supported ASD fieLd tests that vera 1989. This ASD concept has features that conducted by Bechtel for utilities between ensure the high degree af reliability that is 1984 and 1988. This faurth~eneratian needed in these high capacity utility paver plant applicatians. These featuxes axe as induccion motor ASD technology reported to industry because i nov being of the follows: reliability that is being demonstrated by this high-pover. high tec.'acology pover electronics
~ 12 aulse invercer to minimize harmonics speed control system. The 7200. hp ASDs have to the utility bus. ~ been in operation for three years ac oxmond Beach The 6250 hpi 890 xpmy 13 ' kvg 1 15
~ UPS fax'SD canal pover to eliminate service factor induction motors that drive the outside influences on the aperatian of Unit 2 Farced Draft Fans are among the highesc the ASD. horsepower motoxs in any of the Southern California Edison generating stations. The
~
Input t ansformer and gxound at the mocor armand Beach plant, located in Oxnard, side of the inverter to prevent high California, has tva 750 MW supercritical line-ta-naut al voltage an the motor. pressure boilers. Because the superc itical, ance-through boiler design does not lend
~ Selective harmonic elimination inverter itself to f equenc anmf f cycling in an control to preclude electrical resonance economic manner, the unit" ara not typically between output filter and mocor. shut dovn at night even though the output may not be needed during those hours.
~
Liquid cooling af thyristors to prevent temperature-related failures. The Unit 2 boiler has been extensively modified to allov operation at reduced minimum The Ormond Beach ASD system is the world's load vhich ls nav 36 MW, down from the 250 MW largest, and most sophisticated of its kind. design value for minimum load. Studies vera These 7200hp ASDs have operated for 3 years made in 1985 of the savings in unit auxiliaxy with no backup system, attesting to the reliability that can be achieved with this power that could be achieved if ASDs ware used to reduce fan speed at night vith the unit approach. output reduced to as lav as 36 MW; These studies showed that the fan horsepower at.
minimum load with inlet vane contxol was 3000 This aaner describes the application cancepc hp per fan and that it could be reduced ta 250 hp per fan vith AsD cancrol. The value af the that has evolved om the EPRZ tests, the GTO- energy saved vas estimated ac up to $ 1.5 PWM ASD technology, field test results of million annually depending an the annual load curve and the future case af fuel.
42 Qf 059-4 EC A paper zecoesseuded and approved by the 'EEE Electr'c Machinery Coassittee of the 1EEE
?over Engiteeritg Society for preseucacion ac the L .=i 1C'/ 0 A
?ES 1992 "inter Ãeecia8, New York, New York. January 26-Zn the meantime. EPRZ conducted 'eld tests ac
- 10. 1992. Manuscripc subnitted July 12, 1991; made the five following locac'ns with four available for pristine January I,S, 1992. dif erenc invexcer technologies:
1984 1. Sierra Pacific Power Co., Ft.
Churchill Plant. 1"2000 hp Boiler Feed Pump ASD vith 12-pulse current 9604150092 960404 source inver er, air cooled.
PDR ADOCK 05000397 D '992 IEEE P PDR
Feed Pump ASD with 12-pulse source inverter, air cooled. current on the motor-side of the'inverter control Line-to-ground to 1985 2. Gulf States Utilities, WiLlow the motor. voltage at Plant. 1-2250 hp Boiler Feed Pump Glen Water cooling of ASD with 6-pulse effective heat removal. thyristars for more modified load- UPS system for ASD commutated inverter (SCR type), eliminate outside influences controls to water cooled.
could affect operation that 1988 3. Zowa Public Service Ca., Neal circllits of ASD fizing 2-6300 hp Boiler Feed PLant. Means to prevent modified load-commutated Pumg ASDs, the output filter resonance between capacitor and the (GTO type), air cooled.
inverter motor that can happen frequency near half and 1987 4. oklahoma Gas Electric electrical resonancebelaw. This Seminole Plant. 2-5000 co., lateral and torsionalhasvibration caused high ASDs, current-source hp FD Fan some ASD installations. in GTO-PWM inverter, air cooled.
1988 5. Sierra Pacific Power Tracy 2000 hp Boiler Feed Plant 1-c~ent source GTO-PWM inverter,ASD, Pump air The EPRZ concept is depicted in Figure caoled. was strictly 1 and installation. applied The ASDs in the Ornond are Beach From the experience gained in these generation in 'echnology development a fourth tests, EPRZ fostered a concept field for an advanced compared to the Ft. as high-horsepower utility deveLopment features Churchill ASD. Specific ASD. General type induction motor follows: in the new ASDs are as for this ASD arefeatures that were identified as follows:
Watemooled rectifier
~
Twelve-pulse input to minimize water-cooled inverter GTOthyristors, harmonics to the power system. and water-cooled thyristors snubber resistors.
~
Input transiormer and system ground Symmetrical eliminating the need for GTO thyristors, blacking I~
INPUT USE OF INPUT FORMER I2~
TRANSFORMER FOR OPERATloN OR SUILTAN TOLERANCE FOR 8US VOLTAGE UPS SWINGS SPIKES ANO INTERRUPTlaNS OC UNK ANO WATER COOLEQ OC UNK INOUCTOR THYRISTORS FOR SIMPUREO COOUNG.
IN+II THYRISTORS FOR REDUNDANCY GTO THYRSTQR CONTROL TO PREVENT RESONANCE 8EnVEEN OUTPUT FK.TER ANO MOTOR OUTPUT FILTER GROUNOINQ OF SYSTEM: TO STA8IUZE MOTOR VOLTAGE ANO OC UNK VOI.TACE MOTOR MOTOR rlgure 1 PREFERRED CONFIGuRATION FOR LARGE POWER PLANT ASD TYPICAL 4160 VOLT SYSTEM 2
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The control is implemented by one 80286 microprocessor vhich provides the regulator, protective and diagnostic functions and a self-checking diagnostic pragram at power up.
The regulator functions include a outer speed loop vith inner control loops for motor torque, current and flux. In addition, a SHE (Selec"ive Harmonic Elimination) Cunctian is implemented by PHM (pulse width modulation of c'rent the inverter output current to prevent high Vorrnol inverter outout current and torque at the resonant frequency of the LC load circuit. Figure 3 shows an example of the FWM pattern for SHE.
The liquid cooling system is a self-ventilating closed loop system using a II LII 8" deianized water/glycol mixture with forced circulation and liquid to air heat exchanger for 50'C ambient air. Redundant full capacity gl L pumps and heat exchanger fans vith automatic change-over are supplied. The cooling system removes the losses of the thyristor devices and snubber resistars.
PWM inverter output current for eiiminotion of 5th ond itn hormonic current After start-up of the ASD equipment in June, 1988, tests were conducted to verify the Can paver over the speed and load range with ASD
=:-"=.= 3 Seleciive,'-,'chic,". c =iimino;i".n cant ol. Test" had been made before the installation of the ASDs to obtain Can paver measurements vith vane cont ol. The results of the tests, shown in Figure 4, verified thyristors in series, each having a peak calculations made before the start of the repetitive forvard voltage rating of 4500 project. Motor input frequency and motor volts and peak reverse valtage rating of 4000 speed for different MH loading are shown in volts. The peak maximum voltage applied by Table 1.
the c'rcuit is 5900 volts, again permitting Cull capability with three GTO's operational t
nd one shorted. The GTO devices operate at The manufacturer of the PD Cans recommended F 05'C maximum, again belov the design junction fan rotor replacement with a new rotor design emperature of 125'C. Each thyrsitor device with less propensity to develop fatigue has an R-C snubber network, voltage equalizer cracks. Calculations and tests vere performed resistor and a gate driver which is optically vith old and new rotors (Figure 4).
coupled to the low voltage cont ol system.
Figure 4 OAMONO 8EACH - FO FANS AS0E MOTOR SHAFT HORSEPOWER vs. GROSS MW QLO ROTOR VANE CQITIICL TEST>>
4XN QLO AOTQII VAIIE COIITIIQLCILC QIO tOTQII CALO @SO TEET ATO>>
~ CILC IIEW IIOTQII e TEST IIETIAOTOII a, CLLC OLO IIQTQII C2 cILQ QLQ IIQTQA 0 TETT IXD KYCQII 200 xe 400 500 IIIW OUTPUT
pERcENT THD FlgLIre 5 CALC TEST Na CALC NO TEST THD-V INPUT RPM FILTER FILTER FILTER FILTER 100 4.95 1.3 97.5 3.57 0.5 75 5.3 2.25 93.7 3.27 0.7 50 4.3 1.9 57 3.1 0.5 CILCULLTTOTHO 25 3.14 1.35 40 2.2 'I.O WITHOUT FILTTA 35 1.9 Tee'T WIO FILTEA THO TIARAT THOV 3 WITH F T4 A F4A ~C.
CALCULATKOTHO WITH F%.TEA TfTTXO TWO WITH FILTTA I I I I I I I I I I I I 25 50, TS 100 IL AFM TABLE 1 ASD CONTROL OF FD AIR AT 1. The output voltage, current, and volts ORMOND BEACH per hertz praf iles required field adjustment to allav rated output voltage HE hr BBH of the ASDs.
750 58 ~ 5 833 930,000 2. The transformer taps on one input 56 ~ 25 802 900,000 transformer were set. on the lowest tap
~667 40 '8 580 660,000 and required ad)ustmont.
@ 24.02 21 76 342 310 400,000 350F000
- 3. An intermittent internal electrical noise source caused an extra zero crossing in the control voltage to tho ASD causing erroneous operation.
Original calculations had shown a maximum 4. The input transformers had a damaged voltage total harmonic distortion of 5.24 at sudden pressure relay and developed oil the 13.2 kV bus because of tho rectifior leaks at the oil level gauge.
harmonics. Because of concern for the 5. Leaks developed in the external copper possible effect of these harmonics on other water piping from poor brazing.
plant components, an input harmonic filter vas 6. The cooling fans an tho water-to-air heat installed on the bus. Tests showed harmonics exchangers are noisier than expected.
levels as in Figure 5 with and without tho 7. A delayed auxiliary bus transfer because filter. Without the filter, input THD at full the bus voltage vas maintained by the load was 3.2 percent. With the filters in input harmonic filter capacitors.
service, maximum input voltage THD vas 1.3 8. Input capacitor liquid leaks from percent. Harmonics have not been a problem, shipping damage.
vith or without the filter, and the filter 9. A few isolated electronic component itself has not caused any problems. ASD failures from causes during efficiency at full load vas measured at 97.54 start-up.
unknown as consistent vith the manufacturer's 10. Nuisance ground tripping during start-up expectations. from an overly sensitive ground detector and feeder cable capacitance.
- 11. Cooling vater conductivity alarms during The ASDs vent into service in June, initial system cleanup.
with 12. cabinet viring errors.
relatively fev problems. Tho ASDs 1988 carry an ASD availability guarantee and a multiyear parts Solutions to all these problems except the and labor warranty. Since installing the noisy heat exchanger fans have been ASDs, the plant operators have chosen to implemented.
operate these fans without inlet vanes. Thus, the fans have operated vithout a backup Operation of the forced draft fans vith ASD control system in casa of ASD failuxe. control xecoived immediate acceptance by the control room operators. Problems af inlet Initial problems vere as follavs7 but should be stressed that neither of these ASDs it vanes freezing in one position have been eliminated. The fine control offered by the has ever caused a critical shutdown of a fan ASDs has been far superior to the inlet vane or a shutdown of the generating unit since its control which had a long tradition of problems first day of in-service opex'ation: at this sita:
The heat rate improvement resulting from the ~g~~
FD fans ASDs is shown in Table 2. ~CO The experience with these two 7200 hp induction motor ASDs demonstrates that highly TABLE 2 CULATED HEAT RATE IMPROVEMENT FROM ASDS reliable ASDs for power plants are available.
By using the application engineering approach outlined in this paper and by taking advantage uzamum of these new developments in high power ASD 60 19,771 1038 design, utilities and their industrial 272 10,111 138 customers can now gain the benefits of this 348 9,834 105 advanced technology without the concerns for 425 502 9,656 9,506 91 79 reliability of power electronics.
578 9,522 39 655 9,538 14 732 9,645 10 "Application of Adjustable-Speed Drives for
' Large Power Plant Motors", J. A. Oliver and R.
0 A. Martinson. Pacific Coast Electrical Association, Engineering and Operating There was no observable effect of the ASD Conference, March 17, 1983.
causing degradation of motor performance.
Motor line-to-line voltage and line current "Conversion of Boiler Feed Pump to Adjustable wave shapes with the Unit at 750 MW are shown Operation", Wilbur Montgomery, James A.
in Figure 6. Operating at about 6695 Oliver, Ralph J. Ferraro. Pacific Coast horsepower and 58.5 Hz, voltage and current Electric Association, Engineering and harmonics were as follows: Operating Conference, March 20, 1985.
TABLE 3 "Retrofitting for Variable Load and Sliding HARMONICS TO THE MOTOR AT 750 MW Throttle Operation: Adjustable Speed Drives<<,
LBlZEolliRR E'XQRQLXl, ~vv~ ~~z9~ James A. Oliver, Ralph J. Ferraro, Wilbur Montgomery, Eugene K. Kempers.
Conference, April 24, 1984.
American Power 1 58.5 11, 549 306 5 291 658 13 "Converting Motors in Power Plants To 7 410 263 4 Adjustable Speed Operation with Power 11 640 103 1 Electronics", J. A. Oliver and R. J. Ferraro.
13 760 68 1 CIGRE International Conference on Large High Voltage Electric Systems, September 1,'1986.
output wave shape of the ASD contains no tage spikes. There was no evidence of "Power Measurement and Harmonic Analysis of ditional motor heating or vibration at. any Large Adjustable Speed, Drives", J. A. Oliver operating speed.. and B. Ben Banerjee. ZEEE Summer Power Meeting, San Francisco, July 15, 1987.
"Symmetrical GTO Current Source Inverter for Wide Speed Range Control of 5300 to 4160 volt, 350 to 7000 hp Induction Motors." Paul Figure 6 Espelage, James M. Nowak, Loren H. Walker.
VOLTAGE AND CURRENT WAVESHAPES IEEE-ZAS Annual Conference, October 2-7, 1988, 6695 HP, 58M Hz Pittsburgh, PA.
"Proven Criteria Imperative to the Application of ASDs to Large Power Plant Motor Systems",
James A. Oliver and Marek J. Samotyj. IEEE s v~ arr tso Summer Power Meeting Minneapolis, July 15-19, 1990.
"Lessons Learned From Field Tests of Large Znduction Motor Adjustable Speed Drives, 1984-1989", J 'A. Oliver and M. J. Samotyj CZGRE Conference, August 26-30, 1990, Paris.
Mr. James
- Oliver - S.M. received Herbert W. Weiss - Received the the B.S.E.E (1950) from the BSEE degree from Lehigh University, University of Maine and the M.E.E. Bethlehem. Pennsylvania kt 1952.
(1960) from the Polytechnic Institute He joined General Electric Company of Brooklyn. in 1952 and has worked in various He is the Product Line Manager for capacities related to the installation Adjustable Speed Drives for Bechtel Corporation in Noiwalk, California.
and he managed the EPRI ASD power plant retrofit project starting in 1982.
k.l and design of power electronic equipments and systems adjustable speed motor drives.
He is presently Manager, Advanced System Engineering for AC and Special Process Drives at the GE Drive Systems Plant in Salem, Virginia for His prior experience indudes Vlce4>resident of Engineering for the Mr. Weiss has authored six technical papers on adjustable speed ac National Electric Coil Division of the McGraw Etflson (1971-1978) and drives and holds seven patems. He is a Senior Member of IEEE Rotating Machineiy Specialist for American Electric Power Service Corporat/on (1950-1971).
Mr. Oliver is VfceChalrman of the IEEE Elecuic Machinery Committee, A U.S. Expen on CIGRE Comminee 11 - Rotating Machines and a member of the ANSI C50 Rotating Machinery Committee. He has authored a number of papers related to rotating electrical machinery and adjustable speed drives.
Mr. R. K. (Bob) McCluskey - is cunently a Senior Research Engineer and Project Manger in Southern California Edison's Research Division and responsible for Electronic Controls and Diagnostics, Power Quality Analysis, and Technology Marek Jan Samotyj is a Senior Transfer.
Project Manager in the Power Elecuonics and Controls Program, of the Customer Systems Division. at the Eleculc Power Research Institute Hfs professional background Includes a Bachelor of Science degree in (EPRI) in Palo Alto, CaNomia. Durin Eiectrical Engkteering from lowe State University of Science and 1984, Mr. Samotyj was a Consultant Technology and nineteen years ln the electric uuTity indusuy. He has for Power Electronic Systems at the work experience in the planning, sMng, design, construction and stanu p institute. He joined the Institute as of major steam elecufc generating plants, energy service facilities, and an employee in 1985. pollution control apparatus, as well as research and development associated with emerging advanced technologies including fuel cells, bulk energy storage, electrfc transponatlon, groundJault detection, energy metering, adjustable speed drives, variable speed generation, Before coming to EpRI, Mr. Samotyj was a Research Assistant for the expert monitoring and diagnostics, and most recently utility regulatory Energy Modeling Forum at Stanford University (1982-1985). From 1980 po6cy matters.
to 1981, Mr. Samotyj was a Consulting Member of the Scientific Board of the Future Research Center at Technical University in Wrocfaw, Poland, Mr. McCluskey has served as a utility advisor to the Electric Power and a Consultant for R5D planning strategy with the Commission on the Research Institute, and Is a member in good sta'nding of Tau Beta Pl, Eta National Economic Reform in Warsaw, poland. From 1971 to 1975, he Kappa Nu. and the Air and Waste Management Assoc'ation.
was a Consuming Staff Engineer and project Manager for the polish Ministry of Mining and Energy.
Mr. Samotyj received his B.S. (1969) and M.S. (1971) degrees in Electrical Engineering from SiIeshn Polytechnfcal University of Glbiice, Poland, He received an M.S. In Engineering<conomics Systems from Stanford University In 1985. From 1981 to 1982. Mr. Samotyj was a Fulbrlght Senior Scholar, and the Fellow of the Professional Journalism Program at Stanford University.
He Is a member of the institute of Efectricaf and Electronics Engineers and a member of CIGRF International Conference on Large High Voltage Electric Systems.
Discussion of: ADJUSTABLE SPEED DRIVE RETROFIT FOR ORMOND BEACH FD FANS By: J. A. Oliver, et al.
N. E. Nilsson (Ohio Edison Company, Akron, Ohio)
The authors are to be congratulated for their develop-ment of another excellent paper in a series of papers on adjustable speed drives (ASDs). Perhaps the most important information in this paper is the tabulation of possible problem areas. This reviewer recalls the problems experienced with the isolating transformers installed as part of the ASD system at the Ohio Edison Company R. E. Burger Plant due to harmonic heating which had not been factored into the original design.
Would the authors elaborate on what was done to address the problems identified. Were the cooling fans on the water-to-air heat exchangers noisier than expected because they were defective, or was it due to a differently designed fan than specified2 Vere defective fans replaced2 Vas the fan design modified2 What specifically were the electronic failures2 What impact did the changed bus transfer time have on the system2 What kinds of wiring errors were discovered2 How long did it take to correct them2 The features applied as a result of field experi-ence appear to be very beneficial. How has the control system with a UPS performed in relation to controllers powered from standard plant electrical systems based on the authors'xperience? What was the means used to prevent resonance between the output filter capacitor and the motor? How much reduction in lateral vibration has been realized2
Discussion Question for:
ADJUSTABLE-SPEED DRIUE RETROFIT FOR ORMOND BEACH FD FANS This is an interesting paper on a timely subject. I was especially pleased to see the comments from the operations people concerning the improvement in unit operation.
We are evaluating a project to retrofit FD fans at one of our larger power plants. We are well aware of the efficiency gains, the reduced maintenance, the operation benefits, and the long term improvement in equipment life. Cost to benefit ratios are attractive which means the economic consideration is favorable. However, a question comes t:o mind concerning the investment. Was there dialogue with the pUC on this project before or after its completion? How did Southern California Edison Co. address this expense with regards to the rate base.
it would be interesting to the readers to hear more I'elieve information on this aspect of the project; perhaps Mr. McCluskey could comment.
J.R. Michalec American Electric Power Columbus, Ohio
DISCUSSION 91JPGC 559-5 PWRS ADJUSTABLE-SPEED DRTVE RETROFIT ORMOND BEACH FD PANS BY J.A. Oliver H.W. Weiss R.K McCluskey M.J. Samotyj DISCUSSION BY
¹weH S. Porter Washington Public Power Supply System P.O. Box 968, MS 580 Richland, WA 99352
Discussion KS. Porter (Washington Public Power Supply System): The success of the Ormond Beach Project has prompted us at the Supply System to accelerate the application of adjustable speed drives (ASDs) in two areas, megawatt savings and improved plant performance. Our first application will apply this technology to drive the reactor recirculation coolant,(RRC) pumps. The design of the RRC system relies on two 8900 HP induction motor driven centrifugal pumps to force coolant through the reactor core. Varying the core coolant Qow rate is a primary means of controlling reactor power level. This is accomplished by using a 15Hz motor-generator set to drive the motors at a slow speed and then switching to 60Hz for fast speed. Flow adjustment is accomplished by using hydraulically operated flow control valves, a method analogous to driving ones automobile with the engine at constant RPM and controlling speed using the brakes! Not only is this a waste of energy, but the resulting turbulence causes excessive vibration in the piping systems. The ASD will control flow and reactor power with motor speed, thus conserving energy, eliminating excessive vibration, and reducing mechanical stresses during startups, shutdowns and control rod sequence exchanges.
Our equipment will be similar to that reported in this paper.
The motors are rated for 6900 volts so input and output transformers will be used for the 4160 volt ASDs. A significant development will be a two-train system, as shown in Figure 1, for each ASD with the capability to operate with either one.
For two-train operation, the ASD'will be 12-.pulse input, 12-pulse output. For single train operation, the ASD will be 6-pulse input, 6-pulse output. The capacity of a sinj~e train is 7200 HP or 80 percent of the RRC pump rating. Tn addition to the two-train capability, the ASDs have one extra SCR thyristor in each inverter leg and one extra GTO thyristor in each inverter leg (N+1). Based on the high degree of reliability achieved at Ormond Beach and the redundancy of the two-train system, along with the (N+1) feature, the existing valve control systems and 15 Hz motor-generator sets will be removed at
%NP-2 when the RRC pump ASDs are installed.
It is noted that the paper does not discuss another positive aspect of ASD application, the soft starting of motors. The drives essentially eliminate the high inrush currents typical of motor starting, thus reducing thermal and mechanical stresses.
CLOSURE FOR "ADJUSTABLE-SPEED DRIVE RETROFIT FOR ORMOND BEACH FD FANS" The authors vish to thank the discussers for their contributions vhich add considerably to the breath of the paper.
In response to Mr. Nilsson, the 2 hp cooling fans on the air-to-vater heat exchangers are still noisier than the 6000 hp FD fans when the FD fans are operated at reduced speed. The problem exists because the ASD specification did not address a noise limit on the cooling fans. Without contract language, the ASD manufacturer does not recognize this as a problem.
The isolated electronic failures mentioned in the paper was one GTO and one circuit board failure during the start-up period.
Replacements vere guxckly made. Wiring errors in the ASD cabinet vere related to relays added as part of the syst: em interface.
Once the effect of the harmonic filter in maintaining bus voltage during bus transfer vas seen, the transfer scheme vas modified to trip the filter be fore initiating transfer.
Four major reliability enhancements used vith the Ormond Beach ASD installation are as follows:
~ Grounding of the motor side of the ASD to let line-to ground voltage excursions occur within the input transformer 004
Supplying ASD control gower from a UPS Water cooling of the thyristors N + 1 thyristors and GTO's in each circuit As a result of these features there have been no ASD related trips of the FD fans or of the Unit. Several of the 5 ASD EPRI sponsored field test installations have continued to experience thyristor failures that are either related to high operating temperature or control voltage problems. It appears from experience that the Ormond Beach reliability features significantly improve performance.
Resonance between the output filter and the motor leakage reactance is totally eliminated by the selective harmonic elimination feature of the ASD. In the PHM algorithm, harmonics are eliminated when they can produce a frequency of 150 hz so that there 's no resonance. The harmonics that are eliminated are as follows:
fundamental harmonic frequency fre enc hz order eliminated 11.5 13 150hz
- 13. 6 150hz
- 21. 4 150hz 30.0 150hz There has been no motor vibration, lateral or otherwise, as a result of operating with these ASDs.
004
0 Mr. Porter has pointed out that the approach used to engineer reliability into the ASD system at Ormond Beach has led directly to the decision by Washington Public Power System to install ASDs on their 8900 hp Reactor Recirculating Pumps (RRC) at WNP-2. They have decided to remove the hydraulically operated RRC system control valve and replace it with a spool piece. According to Reference 1, with the dual train system proposed for WNP-2 there would be significant increase in reliability. From Reference 1, the mean time before failure (MTBF) for Ormond Beach would be 48,000 hours0 days <br />0 hours <br />0 weeks <br />0 months <br /> and for WNP-2, 137,000 hours0 days <br />0 hours <br />0 weeks <br />0 months <br />.
ln response to Mr. Hichalec's inquiry, discussions were held with a representative of the Public Utilities Commission after the ASDs went into service (at the request of the PUC). Because of the annual fuel cost savings, which were calculated to be over $ 500,000 per year, and which were verified by tests, before and after the ASD installation, the cost of the ASD installation was allowed in the rate base.
P. K. Steiner and A. B. Giesecke "Increased Availability of Large AC Adjustable-'Speed Drive Systems" American Power Conference Chicago, April 1991.
004
Mr. McCluskey is presently a Senior Research Engineer and Project Manager in Southern California Edison's Research Division Quality Analysis. His professional background includes a Bachelor of Science degree in Electrical Engineering &ozn iowa State University of Science and Technology and twenty years in the electric utilityindustry.
He has work expexience in the planning, siting, design, construction and startup of major steam electric generating plants, energy service facilities, and pollution control apparatus, as well as research and development associated with emerging advanced technologies including fuel ceOs, bulk energy storage, electric transportation, ground-fault detection, energy metering, adjustable speed drives, variable speed generation, expert monitoxing and diagnostics, and .
most recently utility regulatory policy matters.
Mr. McCluskey has served as a utilityadvisor to the Electric Power Research institute, and is a member in good standing of Tau Beta pi, Eta Kappa Nu, and the Air and Waste Management Association.
013
LJ DISCUSSION OF PRO3ECTS Ormond Beach FD Fan ASD's Z6 KY 4 KV I
~4KV< ~
5th 1th ltth 13th 7200 hp 7200 hp Figure 6 ORMOND BEACH FD FAN ASD's Measured harmonic data had been obtained prior to testing the two 7200 hp adjustable speed drives (ASD's) at Southern California Edison's Ormond Beach Plant in 1989. The Qrst use of V-Harm was to calculate the harmonics produced by the ASD rectifier and compare it to test data. Because of the advanced engineering content of the program and the brief instructions supplied by Cooper, three to four weeks were required to develop proficiency in using the program. The Ormond Beach calculations were carried out with close approximation to the Geld test data. The program's output data was simplified by using an auxiliary program.
Figure 6 shows the simplified single line diagram used in modeling the Ormond Beach Plant, Unit 2. Figure 7 provides some additional detaQ for the two 7200 hp ASD's that were installed on the Unit 2 Forced Draft Fans. As can be seen in Figure 7, three-winding 12
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