ML19261D770

LER 79-018/03L-0 on 790527:4 Kv Feedwater Breaker 152-2401 Tripped Open Causing Loss of Power to 4 Kv Bus 24.Caused by Spurious Signal or Momentary Loss of Power to ESFAS Zb Logic Cabinet 2C68L.No Further Action Required

ML19261D770
Person / Time
Site:	Calvert Cliffs
Issue date:	06/21/1979
From:	Davis S, Miernicki M BALTIMORE GAS & ELECTRIC CO.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
Shared Package
ML19261D764	List: ML19261D763 ML19261D770
References
LER-79-018-03L, LER-79-18-3L, NUDOCS 7906260348
Download: ML19261D770 (2)

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I31;' LEt 1C_24 4 kv feeder brea_ker 152-2.401 triced varLctusinG_.a_hss_ofacxer to a kv 1 re!;j ibus 24 (T.S.3.8.2.1). Diesel cenera'or 21 automatically started and enercized I (TFR ! the bus. Breaker 152-2414 '.ias closed restorina norma] off-site acwer via service I i- i- Ltransfomer U 4000-12 at 1034 to 4 kv bus 24 Feeder breaker line-uo to 4 kv bus 24 l

^ :s 1 Ms restored t_o noral at 1151 Rtdugant 4 kv bus 21 remained oterable durina l

!uI lthe event. This is not_a reretitive occurrence. I ii' l l 3 9 50 Sv 5?EY CAUSE C A L.S E CCYP 'c A L v E 200E CCOE EJCCCE CCY7C NENT CC CE sve CCE sw:CCE

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,l. jAn investigation detemined that the orebable cause of the 4KV feeder breaker trio I i,j ;was a scurious sicnal in, or a merentary loss of ocwer to ESFAS ZB looic cabinet i

,i l2C68L. This caused a sourious 4KV bus undervoltage signal in ESFAS resultino in a i

llcad shed signal to the 4KV bus. This lead shed signal automatically caused the I t.,.

l feeder breaker to ocen. No other ecuic ent malfunctions were identified (CONT) i

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S. M. Cavis/M. J. u.iernicki , ,.c._

(301) 224-7942/7962  ;

LER 10. 79-13/3L DOCKET N0. 50-318 EVENT DATE 5/27/79 REPORT DATE 6/21/79 ATTACH"ENT CAUSE DESCRIPTION AND CORRECTIVE ACTIONS: (Cont) and no further corrective action is required.

2311 126

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