ML19326A508

LER 77-106/03L-0:on 771206,two 345 Kv Air Circuit Breakers on K Bus Tripped Due to Fault on Oh Edison Co Beaver Line. Caused by Galloping Conductors on Transmission Line.Load Dispatcher Opened Air Breaker & Reclosed Circuit Breakers

ML19326A508
Person / Time
Site:	Davis Besse
Issue date:	12/22/1977
From:	Beeler T TOLEDO EDISON CO.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
Shared Package
ML19326A497	List: ML19326A496 ML19326A508
References
LER-77-106-03L, LER-77-106-3L, NUDOCS 8002040689
Download: ML19326A508 (2)

Text

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LICENSEE EVENT REPORT REQUIR ED INFORMATION)

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8 60 68 DOCKET NUMSER EVENT OESCRIPTION AND PRC8 ABLE CONSEQUENCES h breakers I

7) ! 21 l At 1741 hours0.0202 days <br />0.484 hours <br />0.00288 weeks <br />6.624505e-4 months <br /> on 12/6/77 and 0237 hours0.00274 days <br />0.0658 hours <br />3.918651e-4 weeks <br />9.01785e-5 months <br /> on 12/7/77, two 345 KV air circuit Bus tripped due to a fault on the Ohio Edison Beaver Line. This de-energized I o i2I l n "K" in the Action Statement of Tech Spec ]

fo,,,;02 Startup Transformer and placed the unit

,o,3, ;3.8.1.1.

There was no danger to the heslth and safety of the public or to unit per- ]

l I o is I l sonnel. At the time of the occurrence, the unit was on the Aux 111arv Transformer l

[a37; gand not on the Startup Transformers. -(NP-33-77-106)

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i;o[lThe cause of this occurrence has been attributed to "calionine cnnam *n-="

b r o n tr o-, 4, *% i i, ,ij l transmission line which caused a trio of two 345 KV air circuit

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,,#21lsvitchvard. The Load Dispatcher opened the n4* b e a ,1- wd*ck ,na -or i m aa - %

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, #3j l 345 KV air circuit breakers which re-energized "K" Bus from the Toledo Edison I

I iii4l l Company Bay Shore Line. 80 1 a o OTHER STATUS IS Y DISCOVERY DESCRIPTION

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68 69 40 3 F 8 9 10 Tom Beeler (419) 259-5000, Ext. 253)

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TOLEDO EDISON COMPANY p' DAVIS-BESSE UNIT ONE NUCLEAR POWER STATION SUPPLEMENTAL INFORMATION FOR LER NP-33-77-106

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l DATE OF EVENT: December 6 and 7, 1977  ;

FACILITY: Davis-Besse Unit 1 IDENTIFICATION OF OCCURRENCE: Loss of 02 Startup Transformer due to fault on the Ohio Edison Beaver Line ,

Conditions Prior to Occurrence: The unit was in Mode 1, with Power (MWT) = 1100 and Load (MWE) = 365. i Description of Occurrence: At 1741 hours0.0202 days <br />0.484 hours <br />0.00288 weeks <br />6.624505e-4 months <br /> on December 6, 1977 and 0237 hours0.00274 days <br />0.0658 hours <br />3.918651e-4 weeks <br />9.01785e-5 months <br /> on December 7,1977, two 345 KV air circuit breakers on "K" Bus tripped due to a fault on the Ohio Edison Beaver Line. This de-energized 02 Startup Transformer and placed the unit into the Action Statement of Technical Specification 3.8.1.I since one of the 345/13.8 KV Startup Transformers was de-energized. .

Designation of Apparent Cause of Occurrence: The cause of this occurrence has been attributed to " galloping conductors" on the transmission line. "Calloping

. conductors" is a movement of transmission lines caused by high winds and ice U uildup b on the transmission lines. This caused the protective relaying scheme to trip two 345 KV air circuit breakers in the switchyard.

Analysis of Occurrence: There was no danger to the health *and safety of the public or to unit personnel.. At the time of the occurrence, the unit was on the Auxiliary Transformer, and not on the Startup Transformers. Also, there was two 345 KV trans-mission linen, one 345/13.8 KV Startup Transformers and two 13.8 KV Buses operable with two independent diesel generators to provide AC power.

Corrective Action: At 1742 hours0.0202 days <br />0.484 hours <br />0.00288 weeks <br />6.62831e-4 months <br /> on December 6,1977 and 0237 hours0.00274 days <br />0.0658 hours <br />3.918651e-4 weeks <br />9.01785e-5 months <br /> on December 7, 1977, the Load Dispatcher opened the air break switch which cleared the Beaver Line from "K" Bus and at 1743 hours0.0202 days <br />0.484 hours <br />0.00288 weeks <br />6.632115e-4 months <br /> on December 6, 1977 and 0238 hours0.00275 days <br />0.0661 hours <br />3.935185e-4 weeks <br />9.0559e-5 months <br /> on Decem-ber 7, 1977, reclosed the two 345 KV air circuit breakers which re-energized "K" Bus from the Toledo Edison Company Bay Shore Line. This removed the unit from the Action Statement of Technical Specification 3.8.1.1. The Transaission and Substation Engineering Division is continuing to study and test proposed resolu-tions to the " galloping conductors" problem.

Failure Data: No previous similar events have occurred.

J i

- 8002040 .

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