ML20039G926
| ML20039G926 | |
| Person / Time | |
|---|---|
| Site: | Big Rock Point File:Consumers Energy icon.png |
| Issue date: | 01/13/1982 |
| From: | Bordine T CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.) |
| To: | Crutchfield D Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8201190313 | |
| Download: ML20039G926 (2) | |
Text
{{#Wiki_filter:_ o /@h ConsumBis POW 8f ( Campany / General O ffices 212 West Wcmegen Avenue. Jecu son, W 43201 *1517) 788-o350 January 13, 1982 i,C; Dennis M Crutchtield, Chief <' / Operating Reactors Branch No 5 U . ~ Nuclear Reactor Regulation d JQg"n. ' dO2a ~} US Nuclear Regulatory Commission H Washington, DC 20555 ,2 i; l .'f DOCKET 50-155 - LICENSE DPR A j\\g < BIG ROCK POINT PLANT - STATION ELECTRIC 4 /p 'j i N DISTRIBUTION SYSTEM VOLTAGES AND DEGRADED GRID PROTECTION Consumers Power Company was requested by NRC letter dated August 18, 1979 to review the electrical power system at Big Rock Point Plant. Subsequent analyses and responses to staff questons were provided oy letters dated Februa ry 19, 1980; August 29, 1980 March 23, 10G1; May 4, 1981; and August 26, 1981. On October 17, 1981 Consumers Power Company submitted a Technical Specification Change Request to provide the additional surveillance require-ments as committed by our previous submittals. By letter dated November 30, 1981, Consumers Power Company received the staff's Safety Evaluation Repcrt - " Adequacy of Station Electrical Distribution System 'Toltages". The SER found our voltage analysis and test results acceptable. On November 25, 1981, prior to completion of the SER by telephone conference call with Messrs Dick Prevatte of the NRC staff and Al Udy of EG&G, Consumers Power Company commit-ted to provide a status report describing the progress of our new station voltage analysis and include any preliminary results or observations. It is the intent of this letter, to fulfill our commitment and thereby eliainate the / need for additional formal reporting of this issue in concurrence with the staffs SER. Consumers Power Company is currently conducting a formal station voltage analysis to determine more precisely the minimum and maximum expected voltages for the Big Rock Point Plant's station power equipment. Since the previous analyses made use of operators' logs and certain industry standards to compute expected voltage levels and the previous analyses considered the station power 2400V mitage razulator to be mt of service, it is felt : hat this aew analy-sis will provide a more accurate account of actual plant voltage conditions. holW oc0182-0010bl42 / 8201190313 820113 PDR ADOCK 050001'.,d P PDR
l .j Dennis M Crutchfield, Chief 2 Big Rock Point Plant Sta Elec Dist Sys -{ Janua ry 13, 1982 In an effort to avoid relying heavily on logbooks and standards, the new station voltage analysis will utilize as inputs the results of a second analysis. The second analysis, which is a system grid voltage analysis, has been recently completed to provide a precise account of the expected minimum and maximum voltage levels for plant use. The station voltage analysis, in turn, will use computer simulation to determine the minimum and maximum expected voltages for station power equipment during various plant operating conditions. In addition, the station voltage analysis will consider the voltage regulator both in service and out of service during these conditions. All of the required computet work has been completed. Approximately 75 load flow cases have been analyzed for overvoltage and undervoltage conditions at the station power equipment. The analysis was conducted considering the 1 2400V, 250 kVA voltage regulator as being both in service and out of service. j The analysis includes the following operating conditions: ] 1. Base Load 2. LOCA 3. Cold Shutdown 4. Diesel Generator Additional load flow cases have also been included in the analysis which simulate the starting of the largest safety-related motor. 1 I Preliminary results indicate that undervoltages will occur on station auxilia-i ry equipment during minimum voltage conditions, but can be alleviated by i changing several station auxiliary transformer tios. Changing the taps will j require new Degraded Grid Voltage Protection System (DGVPS) undervoltage relay set points. Arrangements are currently bein2 made to schedule the proposed J tap changes and set point adjustments. It should be noted, however, that these results and arrangements are preliminary and are subject to possible change.It is expected that the station voltage analysis will be completed by l early spring, 1982. i 1 ~I
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.n & ( Thomas C Bordine Staff Licensing Engineer CC Administrator, Region III, USNRC i NRC Resident Inspector-Big Rock Point i 4 i j l oc0182-0010bl42 --n .---n -}}