ML20213E666
| ML20213E666 | |
| Person / Time | |
|---|---|
| Site: | Beaver Valley |
| Issue date: | 11/07/1986 |
| From: | Kaiser A BBC BROWN BOVERI, INC. (FORMERLY BROWN BOVERI CORP. |
| To: | Taylor J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE) |
| References | |
| REF-PT21-86-366-000 PT21-86-366, PT21-86-366-000, NUDOCS 8611130249 | |
| Download: ML20213E666 (3) | |
Text
o si BBC Brown Boveri Switchgear Products Group esc srown soveri,inc.
Six Sentry Parkway 630 Sentry Park Blue Bell.PA 19422 November 7,1986 Phone:(215)834 7400 Mr. J. M. Taylor, Director Office of Inspection and Enforcement
' U.S. Nuclear Regulatory Commission Washington, D.C. 20555
Subject:
BBC Brown Boveri, ITE 27B Relay (Battery Ground Detector Relay) 10CFR Part 21 Report Gentlemen:
The BBC Brown Boveri 27B (ITE 27B) battery ground detector relay is a directional voltage differential relay. It is used to detect grounds on a DC control bus and to indicate whether the ground is on the positive or negative bus. This relay normally operates an alarm if a ground is detected.
Recently test personnel at Duquesne Light Co. (Beaver Valley Unit 2) detected a problem with this relay (Catalog Number 239G0045) wherein when the sensitivity dial on the front panel was set in the low sensitivity position, and when the control voltage exceeds approximately 132V DC, some of the relays may fail to detect a ground condition on the negative bus. This problem is caused by an insufficient design margin in the reference and biasing networks in the relay's pickup ' circuit.
This problem could result in a condition wherein an alarm is not provided when a ground exists on the negative bus. If a subsequent short also developed on the positive bus, it could result in a short circuit of the batteries without an alarm signal.
As an expedient, temporary corrective action, the front panel " Sensitivity" dial may be turned clockwise to the 10 o' clock position or higher. This willinsure that the relay will respond to battery grounds at all control voltages from 100V through 145V DC. The sensitivity dialis marked with a " dot" at the min position (approximately 7 o' clock) and a
" dot" at the max position (approximately 5 o' clock). It also has " dots" at the 10 o' clock, 12 o' clock, and 2 o' clock positions. The relay will operate indefinitely with settings in this range.
For permanent corrective action, a modification consisting of changing two resistors on the printed circuit board will allow relay operation to be correct for all positions of the sensitivity dial from min to max. This modification will not affect the environmental or seismic qualification.
The modification kit and instructions are available from the manufacturer or the printed circuit board may be returned for modification.
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ii130249Sgo7h42 fg ADOCK O S
i BBC BROWN BOVERI Mr. J. M. Tayltr, Director Office of Inspection and Enforcement November 7,1986 Page2 The location of the ITE 27B relays is shown on Attachment #1 of this report. The end users of this relay are being notified of this condition by sending them a copy of this report.
It should be noted that a previous 10CFR Part 21 report on the ITE 27B (Battery Ground Detector Relay) was sent to the NRC on January 5,1984. (For your convenience a copy of this report is included as Attachment #2). At that time the relay was Catalog Number 239 D0505.
l The problem reported in the January 5,1984 report was corrected by replacing the ITE 27B with a new version of ITE 27B Catalog Number 239G0045.
The problem being reported here would not occur in the ITE 27B Catalog Number 239D0505.
This information is being provided to explain the differences in quantities and location of relays between the January 5,1984 report and this report. Also, since the date of the first report on the ITE 27B (Catalog Number 239D0505) additional quantities of the ITE 27 (Catalog Number 239G0045) have been delivered to end users.
V A. F. KAISER, President Switchgear Products Group EWR/jm i
Enclosure t
e BBC BROWN BOVE RI ATTACHMENT #1 BBC BROWN BOVERI 27B (CAT. f 239G0045)
(BATTERY GROUND DETECTOR RELAY)
Georgia Power Company Vogtle Plant 46 Units Gulf States Utilities River Bend 10 Units SMUD Rancho Seco 2 Units
- Duquesne Light Co.
Beaver Valley 2 4 Units
- These units were corrected during the evaluation.
Note:
The ITE 27B relays (Catalog Number 239D0505) were delivered to TVA (IIartsville and Phipps Bend), however, these have not been converted to the ITE 27B (Catalog Number 239G0045), therefore they are not included in this report.
l
[
. ? BBC Brown Bovsri Electric, Inc.
sROWN 00 VERI Manufacturer of I.T-E Sectrical Power Equipment ATTACHMENT #2 January 5, 1984 Mr. R. C. DeYoung, Director Office of Inspection & Enforcement U. S. Nuclear Regulatory Commission Washington, D. C.
20555
Subject:
Potential Problem with Brown Boveri (ITE 27B)
Battery Ground Detector Relay
Dear Mr. DeYoung:
The ITE 27B Battery Ground Detector Relay is a directional voltage dif ferential relay. It is used to detect grounds on a de control bus and to indicate whether the ground is on the positive or nega-tive bus. This is accomplished by measuring the voltage from the positive bus to ground and the voltage from the negative bus to ground. Normally, the relay operates an alarm circuit.
Although there have been no failures of this relay reported, a recent review of the design of the ITE 27B relay has indicated that a portion of the solid state circuitry can be overstressed under certain operating conditions. Operating in this mode could reduce the useful life of this device.
The overstress condition would occur as follows:
1)
Upon occurence of a solid ground on one side of the dc control power system, the appropriate contact closure would take place and alam indication would be given.
[
- 2) At this time a portion of the relay's circuitry would be overstressed for the duration of the grounded condition.
I Should a failure occur due to this overstress, it would i
likely cause another contact closure indicating that a ground condition also exists on the opposite polarity of i
the de control power circuit. The consequences of this incorrect operation would depend on how the relay's output l
contacts are applied by the end user.
i l
It is not anticipated that a failure of the ITE 27B could result in l,,
creating any substantial safety hazard, however operations personnel i
should be alerted to this potential condition to avoid confusion.
N k-- h s.ne,sne owon
(
sadne Hed, PA 19477 *(215)828 7400 i
r BBC Brown sov:ri electric, Inc.
enow sown ATTACHMENT #2 Mr. R. C. DeYoung January 5, 1984 Page 2 t
~ Users who have these relays in their systems will be notified of this condition. Arrangements can be made with Brown Boveri for modi-fications or replacement parts whichever is more appropriate for the users operating status. The relay case need not be removed from the panel in which it is mounted. Only the dravout element of the relay is affected.
A list of users of the ITE 27B relay in systems identified as Class 1E is included as an attachment to this report.
}
D.
. DUVALL Vice President DDD/jm Attachment ec:
A. E. Boetticher D. Dalasta C. L. Downs e
l C. E. Kunkel W. E. Laubach E. W. Rhoads i
l 1
l
--,--,.--r-,--~__
f 4ATTACHMEt4T #2 ITE-27B BATTERY GROU'm DETECTOR RELAY (CATALOG flVMBER #23900505)
The following have been identified from Brown Boveri records as Class 1E Safety Related Applications:
HORSHAM CUSTOMER TOTAL S.O. #
CUSTOMER P.O.
UNITS END USER 33243 Switchgear 53106 30 TVA (Stride Project) 33244 Division 33294 33296 35149 Switchgear 54236 6
Gulf States Utilities 35590 Division 54237 River Bend 37072 53247 36117 Switchgear 53248 8
Georgia Power 36676 Division 53247 Vogtle Plant 40046 53248 39229 Square D Co.
12-43103 12 Georgia Power Peru, Indiana Vogtle Plant l
40334 Square D Co.
12-46045 5
SMUD Peru, Indiana Rancho Seco a.
1/5/84 1