ML18086A692
| ML18086A692 | |
| Person / Time | |
|---|---|
| Site: | Salem  |
| Issue date: | 06/16/1981 |
| From: | Mittl R Public Service Enterprise Group |
| To: | Varga S Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8106220285 | |
| Download: ML18086A692 (2) | |
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- -* e PS~G Public Service Electric and Gas Company 80 Park Plaza, T16D Newark, N.J. 07101 201/430-8217 Robert L. Mittl
- General Manager - Licensing and Environment June 16, 1981 Director of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, D.C.
20555 Attention:
Mr. S. A. Varga, Chief Operating Reactors Branch 1 Division of Licensing Gentlemen:
SECOND LEVEL OF UNDERVOLTAGE PROTECTION NO. 1 UNIT SALEM NUCLEAR GENERATING STATION DOCKET NO. 50-272 The following information concerning the Salem second level of undervoltage protection is provided in response to tele-phone discussions with members of your staff.
In our August 5, 1980 response to your request for an analy-sis of the Salem voltage profile resulting from the. loss of one of the 500/13.8 kV transformers, it was our intent to indicate that the second level of undervoltage protection scheme would operate.
This conclusion was reached on the basis of our previously submitted analysis by simply dou-bling the impedance Closs of one 500/13.8 kV transformer) between the 500 kV grid and the 13.8 kV system.
The result-ing 13.8 kV voltage becomes.865 P.U. Cwas.903 P.U. in two transformer analysis) and the 4.16 kV voltage becomes.8824 P.U. (was.9226 in two transformer analysis).
The second le-vel of undervoltage protection is set for.91 P.U. (on 4.16 kV) with no time delay, and therefore it will operate causing the stripping of the vital busses.
The diesel gen-erators will start and the vital busses will be sequentially loaded.
This is the operating mode which will result due to the postulated chain of events.
It should also be noted that the restored offsite system is still available, providing a back-up for the diesel generators.
The Energy People p
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Should you have.any questions in this regard, do not hesi-tate to contact us.
Very truly yours, EAL:vh CC:
Mr. Leif Norrholm Senior Resident Inspector