ML19241A580
| ML19241A580 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 03/29/1979 |
| From: | Beckwith R BECKWITH ELECTRIC CO., INC. |
| To: | Hendrie J NRC COMMISSION (OCM) |
| Shared Package | |
| ML19241A582 | List: |
| References | |
| NUDOCS 7904170099 | |
| Download: ML19241A580 (2) | |
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1181162ND STREET NORTH a LARQO[F.LORIDA 33543 l
(813) 535-3403
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Ma rch 29,19 79-b
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M r. Joseph M. Hendrie, Chairman Nuclear Regulatory CommiTsion 1717 H. St ree t N. W.
Washington, D, C.
20555
Dear Mr. He nd rie,
t @ I believe you will be interested in the enclosed material which availabic to the pre sidents of the 100 large st electric utilitie s in the U. S. as well as the utility trade magazines. The motor bus transfer problem could contribute to an incident auch a s occured at the Tnree Mile Island Station, Unit !!2 nuclear plant. You may find the material of value to you in this inve s t igation.
Sincerely, l ;oby' hi N
c) hobert W. Beckwith
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Pre sident RWB:jv enc.
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ALL UTILITY TRADE MAGAZINES FOR:
BECKWITH ELECTRIC CO.,
INC.
March 29, 1979 11811 62nd Street tior t h Largo FL 33543 r
FOR FURTHEk INFORMATION CONTACT:
FOR IMMEDIATE RELEASE i
Mike A.
Wyatt Phone 813/535-3408 POWER TRANSFER RELAYS One single event which could complicate the normal shut down of a nucle power plant is an improper t ansfer of the plant motor bus as explained in a paper " Power Transfer - How and Why" available from the Beckwith Electric Company, 11811 62nd Street North, Largo, FL 33543, Phone:
(813) 535-3408.
The possibility exists of simultaneous failure to vari plant motors just at the crucial instant of a plant shut down by an out of phase combination of the trapped flux voltage on the motor bus with the new source.
This particular failure mode can be avoided by use of high speed bus transfer circuit breakers supervised by a combination of the M-0236 Power Transfer Relay and M-0245 High Speed Sync-Check Relay manufactured by Beckwith Electric.
Extensive bus transfer simulations are underway at Beckwith Electric, as well as major electric utilities and engineering companies, to confirm the problem and the use of the f
h-0236 and M-0245 relays as a reliable solution.
Results of these stud and simulations over the past two years indicate the potential failure mode does exist and that the available relays will reliably solve the problem.
While no cases of damage by motor bus transfer have been confirmed for nuclear plants, there have been several instances of dama transfer at fossil fueled plants.
This issue was discussed in depth at a seminar held at Beckwith Electric in January of this year.
All major utilities were invited and several attended.
Enc:
" Power Transfer - How and Why"
,'y, M-0236 Application Guide
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M-0236 Specifications a A rD 0 5 J-M-0245 Specifications lju
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