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Doble Engineering Company

Troubles & Failures Report8/1/2004 To 9/30/2004

Arrester - TroubleIncident # Incident Date Report Date Photo File Name

43921 4/29/2003 10/14/2004 IID200401,02,03

Manufacturer Model Number KV Mfgr Year

Joslyn 8110D0001J096 51-100 kV

Method of Detection

Cause of Failure

No apparent trouble in the system.

Comments

(Photo was unavailable for release in this report.)

Arrester - In-Service FailureIncident # Incident Date Report Date Photo File Name

43922 11/15/2003 10/14/2004

Manufacturer Model Number KV Mfgr Year Joslyn ZE 51-100 kV NONE

Method of Detection

Cause of Failure

Line down.

Comments

B/O lightning arrester on RNO breaker.

Arrester - In-Service FailureIncident # Incident Date Report Date Photo File Name

43961 12/25/2003 2/23/2004 SNPD2004_Rept04


Ohio Brass 219576 101-150 kV 2001

Method of Detection

Cause of Failure

Unknown - clear day, no moisture found internally.

Knowledge Is PowerSM

Apparatus Maintenance and Power Management For Energy Delivery

Troubles Failures Report Page 1 of 28

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Comments

Arrester failed only about 3 months after it was installed as a replacement to an old SiC

arrester. O.B. had identified arresters that had a problem with moisture ingress,

but this S/N was not part of their recall. O.B. performed an analysis, but no cause

was identified. (Photo was unavailable for release in this report.)

Bushing-Condenser (oip) - TroubleIncident # Incident Date Report Date Photo File Name

43924 5/2/2003 10/14/2004


General Electric PVDB1155202 11-15 kV 2002

Method of Detection

Cause of Failure

Comments


43969 8/19/2003 3/25/2004


General Electric 550W1600UG 451-500 kV 1981

Method of Detection

Failed Doble power factor test.

Cause of Failure

Comments

Type U 500KV Bushing - evidence of water entering at top terminal gasket.


43942 3/8/2004 3/23/2004 sce2004_rept01a,b


General Electric FK69-3500-1 51-100 kV 1962

Method of Detection

Cause of Failure

Comments

Type U bushing on circuit breaker failed. (Picture was unavailable for release in this report.)


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Bushing-Condenser (oip) - Failure at TestIncident # Incident Date Report Date Photo File Name

43891 8/13/2004 8/16/2004


Lapp POC 101-150 kV

Method of Detection

Bushings: C1 Power Factor

Cause of Failure

Bushing

Comments

Cable - TroubleIncident # Incident Date Report Date Photo File Name

43934 6/4/2003 3/18/2004 MWD2004_Rept01A(thru C).JPGManufacturer Model Number KV Mfgr Year

Rome 0-5 kV 1982

Method of Detection

Cause of Failure

Insulation failure due to old manufacturing formulation.

Comments

The hydro plant tripped due to utility excursion. After receiving permission from the utility for

restart, the unit tripped as soon as the breaker closed. A Megger test revealed a problem

with one of the conductors from the unit circuit breaker to transformer. A hole slightly larger

than a quarter was found in the failed cable. (Photos were unavailable for release in this

report.) As preventative measures, the asset owner will survey other 14 hydro plants

for similar old XLP cables and continue cable testing every 5 years; they may also consider

a shorter interval between cable tests, particularly for older cables.

Capacitor - In-Service FailureIncident # Incident Date Report Date Photo File Name

43926 1/5/2004 4/1/2004


Westinghouse Electric series caps 201-250 kV 1966

Method of Detection

Cause of Failure

Comments

Cap bank was called to bypass. Bypass switch got part way closed causing extended arcing (blowing

up glass & burning up contacts). Bank was installed in 1966. Parts are wearing out and getting hard to get.


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Circuit Breaker - TroubleIncident # Incident Date Report Date Photo File Name

43947 8/15/2001 4/15/2004


Westinghouse Electric 242-SP-50 251-300 kV 1980

Method of Detection

Cause of Failure

Failed air compressor.

Comments

AØ DID NOT CLOSE. BREAKER USED UP ENOUGH AR TO LOCK OUT AIR COMPRESSOR. BROUGHT

IN LOW AIR ALARM, AND LOCKED OUT. CLOSING CIRCUIT TO GCB. FOUND BROKEN RINGS ON

PISTON AØ MECH; ALSO FOUND BROKEN 1" ROLL PIN IN PISTON ROD. BOLTS IN OPENING

VALVE ASEMB.

Circuit Breaker - In-Service FailureIncident # Incident Date Report Date Photo File Name

43962 1/7/2003 2/23/2004


Siemens FCV-500 11-15 kV 1979

Method of Detection

Cause of Failure

Trip coil failure.

Comments

Circuit switcher operated to clear fault, interrupting service to approx 5,000 customers.

However, circuit switcher would not close again, and motor operator had to be repaired.


43952 1/17/2003 4/15/2004


McGraw Edison AHJ-60-138-10000 151-200 kV 1973

Method of Detection

Cause of Failure

Mechanism lubrication dried up.

Comments

FOUND ALL BEARING STIFF, OR NOT MOVING AT ALL IN MECH. R & R TRIP ASS.

REMOVE AND DISASSEMBLE STIFF TRIP LINKAGE, LUBE PINS

AND FREE UP STIFF BEARINGS. NOW THE BREAKER LATCHES EVERY TIME.


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43946 1/22/2003 4/16/2004


Siemens SPS2-245-40-1 201-250 kV 2001

Method of Detection

Cause of Failure

While being energized, pole 3 went phase to ground.

Comments

Removed SF6 gas & removed pole 3 cover. Found that pole 3 did flash to ground.

Looks like it flashed from the corona ring to the tank. 7 of the same voltage level

and model in the 2000/2001 mfg year were internally inspected.

Circuit Breaker - Trouble

Incident # Incident Date Report Date Photo File Name43951 2/5/2003 4/15/2004


Westinghouse Electric GO-3D 51-100 kV 1950

Method of Detection

Cause of Failure

Exhaust piston stuck.

Comments


43916 2/24/2003 4/4/2004 BPAT200414-19


ABB 550PM 50-30 > 500 kV 2003

Method of Detection

Cause of Failure

Restrike

Comments

Breaker sent a trip command via SCADA. A & B phases interrupted approximately 320

Amps. C-phase continued to carry load current for approximately 16 cycles. Breaker

Failure Relay operated and cleared the bus. Breaker was commission tested and in

service less than 6 weeks. (Photo was unavailable for release in this report.)


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43953 3/24/2003 4/15/2004


McGraw Edison CH-60A-69-3500 51-100 kV 1974

Method of Detection

Cause of Failure

Comments

FOUND CLOSE COIL OPERATOR IN PIECES AND CLOSE COIL BO, REBUILT CLOSING MEC. AND REPLACED COIL.


43968 4/2/2003 3/25/2004

Manufacturer Model Number KV Mfgr Year Alsthom HGF-1014 201-250 kV 2002

Method of Detection

Cause of Failure

Internal contamination from factory

Comments

Internal fault B Phase to ground 15000amps

Circuit Breaker - TroubleIncident # Incident Date Report Date Photo File Name43950 4/15/2003 4/15/2004


Mitsubishi 101-150 kV 2001

Method of Detection

Cause of Failure

B/O closing coil.

Comments


43954 5/22/2003 4/15/2004


McGraw Edison AHJ-60-138-1000 101-150 kV 1973

Method of Detection


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Cause of Failure

Mechanism lubricants dried out.

Comments

Breaker had problems closing.


43939 7/1/2003 10/14/2004 PAC200402


ABB 145PMI 101-150 kV

Method of Detection

Cause of Failure

Broken stud that mounts the stationary arcing contact inside the stationary contact assem

CommentsThis was likely caused by a stress concentration due to a surface defect such as a crack at

the root of the threads. (Photo was unavailable for release in this report.)


43948 7/7/2003 4/15/2004



Method of Detection

Cause of Failure

Comments

07/07/03 Breaker timing problem. Timed breaker, found out by 15 ms, will need to come

back to adjust. 07/10/03 Adjusted phase-to-phase timing on breaker. Turned

screw on close pilot valve out to speed up tank 3; it is still slower than factory spec.


43973 8/2/2003 4/6/2004


General Electric FK-144-250Y 11-15 kV 1956

Method of Detection

Cause of Failure

Fault started at line arrester, breaker did not clear fault.


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Comments

Breaker tank ruptured. Breaker was a total loss. (Lightning in area.)


43937 8/10/2003 5/18/2004 MWD2004_Rept04A(and B).jpgManufacturer Model Number KV Mfgr Year

Siemens SPS-38-23-1 36-50 kV 1995

Method of Detection

Cause of Failure

Comments

This CB has been leaking since installation. Utility personnel spent a couple of days

troubleshooting this CB using conventional gas detection methods but were not successful.

The amount of leak was very minimal; about 5 pounds of SF6 gas was added once a yr.GIS came to the power plant on 10/27/03 to perform laser imaging on the breaker. The

camera detected a leak on the supply line fitting of A-Phase; no other leaks were found.

Utility personnel performed soap bubble test to confirm the leak and then adjusted the fitting.

Re-shot of the fitting showed no more SF6 leak. (Photo unavailable for release in this report.)


43949 8/17/2003 4/15/2004



Method of Detection

Cause of Failure

Comments


43923 9/10/2003 10/14/2004 IID200304,05,06,07,08,09


Siemens BZO121406 151-200 kV 1984

Method of Detection

Tested the bushings and found variable capacitance.

Cause of Failure


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Comments

Replaced the breaker. (Photos unavailable for release in this report.)


43966 10/2/2003 2/16/2004Manufacturer Model Number KV Mfgr Year

I.T.E. 242-GA63-30C 201-250 kV 1981

Method of Detection

Cause of Failure

Deterioration of capacitor.

Comments

Replacement Capacitors not available-Pole 2 destroyed.


43915 10/18/2003 4/4/2004 BPAT200412,13


ABB 550PM 40-30 > 500 kV 2003

Method of Detection

Cause of Failure

Comments

Breaker sent a trip command via SCADA. A & B phases interrupted approximately 250

Amps. C-phase continued to carry load current for approximately 16 cycles. Breaker

Failure Relay operated and cleared the bus. (Photos were unavailable for release in this report.)


43960 10/28/2003 2/23/2004


Siemens FCV500 11-15 kV 1979

Method of Detection

Cause of Failure

Trip coil burned, breaker did not operate, took substation off line.

Comments

Failure caused interruption of service to approx. 5000 customers.


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43943 11/10/2003 3/23/2004 sce2004rept_02


ABB 72PMI31-12 51-100 kV 2000

Method of Detection

Cause of Failure

Shorted B-phase close coil causing.

Comments

Close signal was initiated via automatic capacitor controls, B phase close coil

leads were shorted. X relay contacts welded closed causing cb to pump until A phase

interrupter failed. It appears the cb close-opened. (Photo unavailable.)

Circuit Breaker - In-Service Failure

Incident # Incident Date Report Date Photo File Name43909 11/16/2003 4/4/2004 BPAT200401, BPAT200420


Brown Boveri Company 72 PM 51-100 kV 1988

Method of Detection

Cause of Failure

Bird droppings from an overhead structure washed down onto the bushings by the rain.

Comments

2 entrance bushings failed. Repair of the breaker required an internal inspection, replacement bushings and

unknown internally damaged parts to be replaced. Time to repair was longer than replacing the breaker

from stock so bkr was replaced. Additionally, the load lost needed to be restored. (Photos unavailable.)


43940 11/26/2003 12/1/2003


High Voltage Breakers HVB362 301-350 kV 2003

Method of Detection

Cause of Failure

Defective material in the dashpot piston.

Comments

New breaker not in service. Relay doing final trip testing. Got pole disagreement

alarm. Found bent linkages in the mechanism of one phase. HVB sent factory people

to investigate. Found damage to linkages in mechanism, the aluminum cast support

conductor that holds the puffer piston, the puffer piston, the Teflon nozzle, and

the stationary contacts. HVB removed and replaced the whole phase. Took damaged


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phase to factory for investigation. HVB acted quickly and performed all repairs

at no cost to utility. Report available.



I.T.E. VRK-15-12 11-15 kV 1972

Method of Detection

Cause of Failure

Failure of mag latch and mech to keep breaker in the tripped position.

Comments

ITE VRKs have a history of mag latch failures and parts are no longer available.


43913 1/6/2004 4/4/2004


Pennsylvania Transformer RHE-84L 201-250 kV 1965

Method of Detection

Cause of Failure

Latch valve failed due to lack of lubrication.

Comments

Trouble: OCB failed to reclose. Temperature -32 degrees. Mechanism does not move.

Corrective action - Removed and cleaned latch valve. Cleaned and lubed mechanism.


43912 1/6/2004 4/4/2004


Pennsylvania Transformer RHE-84-230-15000 201-250 kV 1965

Method of Detection

Cause of Failure

Comments

Trouble: OCB failed to reclose. Temperature -32 degrees. Mechanism does not move.

Corrective action - Removed and cleaned latch valve. Cleaned and lubed mechanism.


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43964 1/29/2004 2/23/2004


Siemens FCV500 11-15 kV 1979

Method of Detection

Cause of Failure

Trip coil burned, circuit breaker failed to operate on distribution circuit fault.

Comments

When the 12 kV circuit breaker failed to operate, backup relaying sensed the fault

and opened the 115 kV circuit switcher, interrupting service to approximately 5000

customers. This was the 3rd incident in 4 months where failure of a FCV-500 trip

coil caused a station to trip off line.


43956 3/19/2004 4/15/2004


Allis-Chalmers FC-500-A1 11-15 kV 1974

Method of Detection

Cause of Failure

Trip mechanism frozen; lubrication dried up.

Comments

ACB WAS OVERHAULED 2 YRS AGO. PLAN TO REVISE LUBRICATION PROCEDURES ON BREAKER

MECHANISMS. THIS ACB FAILED TO OPEN ON A FEEDER FAULT CAUSING THE

BUS OVERCURRENTS TO CLEAR AN ENTIRE BUS SECTION (5 ADDITIONAL CIRCUITS)


43888 7/6/2004 8/4/2004 3449164710432161.JPG


ASEA-Brown Boveri 242PMG50-30 201-250 kV 2000

Method of Detection

Visual Inspection

Cause of Failure

Leak/Gasket

Comments

Moisture trapped in the mechanism housing caused massive corrosion damage and multiple

breaks on the disc springs on this AHMA-11 mechanism. The mechanism is not repairable

and is a total loss. Some water found an access into the mechanism housing, apparently

through some inadequate sealing procedures during installation. The drain hole


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was removed and over one quart of water poured out from the mechanism. A new mechanism

was installed and proper installation and sealing procedures were followed.

Circuit Switcher - TroubleIncident # Incident Date Report Date Photo File Name

43971 7/3/2003 3/25/2004


S&C Electric 2040 51-100 kV 1988

Method of Detection

Cause of Failure

Voids & unmelted plastic in Delrin Spring Carrier allowing Red Target to actuate even though there was no SF6 leak.

Comments

We have had 30 or so of these Red Target-Low Gas problems and have been sending

back the Interrupters for a porcelain credit. We were told by the factory that units

between 1988 and 1991 did have manufacturing problems with the carrier, but, notrouble since 1991. Then we had several 1992 and 1995 failures and contacted them

again. Recently we had the S&C Factory research this problem thoroughly and they

have a new repair kit that we can install in the field.


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43928 7/31/2003 4/1/2004


S&C Electric Mark IV 301-350 kV 1978

Method of Detection

Cause of Failure

Unknown. Shipped failed interrupters back to S&C.

Comments

Interrupters on south pole failed to interrupt. Opened circuit with air break arms.

Circuit Switcher - In-Service FailureIncident # Incident Date Report Date Photo File Name

43927 11/1/2003 11/1/2003 IPC2004_Rept03

Manufacturer Model Number KV Mfgr Year S&C Electric S&C 2020 51-100 kV 1994

Method of Detection

Cause of Failure

Comments

Problem with this design, if the circuit switcher fails to trip, (trip coil failure)

the agastat times out and the disconnects open even though the SF6 bottles do

not. The clearances on the open 69 kv disconnects are too close and the energized

line was flashing over phase to phase. This C/S needs a redesign, or we could roll

the C/S 180 so the open disconnects would not be energized when the gas bottles

were closed. (Photo not available for release in this report.)


43914 2/3/2004 4/4/2004 BPAT200403,04,05,


S&C Electric Mark IV > 500 kV 1979

Method of Detection

Cause of Failure

Mechanical failure of the interphase linkage.

Comments

While attempting to close circuit switcher via SCADA, the reactor and bus LOR's

operated. South bus LOR reset. Operator reported only two phases closed and linkage

between phases on the ground. (Photo unavailable.)


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CT - In-Service FailureIncident # Incident Date Report Date Photo File Name

43967 11/27/2003 2/15/2004


Haefely IOSK-245 201-250 kV 1985

Method of Detection

Cause of Failure

Internal fault

Comments

CT Column caught on fire & failed due to A Phase to Ground fault. This is a free-standing

oil-filled CT.

CT - In-Service FailureIncident # Incident Date Report Date Photo File Name

43890 11/27/2003 8/16/2004 27131316710412281.ppt

Manufacturer Model Number KV Mfgr Year Trench Electric IOSK-245 201-250 kV 1984

Method of Detection

Other (See Comments), Relay Operation

Cause of Failure

Deteriorated Insulation

Comments

This is for a 230kV free standing CT that failed catastrophically while in service.


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Insulator - Trouble

Incident # Incident Date Report Date Photo File Name

43936 10/21/2003 3/18/2004 MWD2004_Rept03A(thru H).JPG


Other 201-250 kV 1933

Method of Detection

Cause of Failure

Unknown cause but note age of equipment.

Comments

One insulator stack pulled completely away, littering the station floor with insulator

material. (Photo unavailable.)

PT - TroubleIncident # Incident Date Report Date Photo File Name

43935 6/10/2003 3/18/2004


General Electric JVM 0-5 kV 1979

Method of Detection

Cause of Failure

Failure attributed to age of the equipment.

Comments

Both units tripped offline. From investigation, both fuses on the primary side

were found blown. TTR revealed shorted turns in the faulty P.T. The P.T. was replaced

with an old spare; new P.T.'s were ordered and will be changed-out at the next scheduled

maintenance. As preventive measures, other hydro plants will be surveyed for

the same type and manufacture P.T., of the same vintage, and consideration given to

performing insulation resistance tests on older P.T.'s during annual shutdowns.

Reactor - In-Service FailureIncident # Incident Date Report Date Photo File Name

43899 2/21/2004 9/14/2004


Trench Electric Shunt 26-35 kV 1981

Method of Detection

Other (See Comments)

Cause of Failure


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Deteriorated Insulation

Comments

After the reactor circuit breaker tripped, a lockout alarm indication was given.

A turn-to-turn failure occurred on the inside package of the reactor. Trench stated

that switching surges over long term operation can cause a shorted turn that creates

a high circulating current blowing out the winding. At 23 years old Trench stated

that it served its useful life. Inspection of other units was suggested. Reactorsof this age don't have arresters. New ones do to protect from TOVs during switching.

Consequently, we will be adding arresters to the other reactors in service.

Regulator - In-Service FailureIncident # Incident Date Report Date Photo File Name

43938 6/3/2004 3/25/2004 PAC200401a,b,c


Siemens JFR 16-20 kV 2002

Method of Detection

Cause of Failure

Spring failure - Siemens has redesigned the spring to a compression type.

Comments

We have seen several new model JFR regulators with this problem. Usually when a

drive spring breaks the operating mech jams. However this regulator tried to go

through the neutral position with only motor drive and caused an open circuit at the

reversing switch. (Photo was not available for release in this report.)

Relay - In-Service FailureIncident # Incident Date Report Date Photo File Name

43963 1/28/2004 2/23/2004


Basler BE1-51 N/A 1996

Method of Detection

Cause of Failure

Relay housing did not short CT circuit when relay was pulled for maintenance.

Comments

When the relay technician was removing a Basler BE1-51 relay for maintenance, theshorting device did not make a connection to the CT circuit. When the paddle was

removed, technician heard buzzing noise (from CT opening), then differential relay

operated, opening circuit switcher. Service interrupted to about 5000 customers

for several minutes until relay re-installed and station put back on line.


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Switch - TroubleIncident # Incident Date Report Date Photo File Name

43911 5/14/2003 4/4/2004 BPAT200402


(No MFR Listed) TA-3A 251-300 kV 1964

Method of Detection

Cause of Failure

C-phase of the disconnect mechanically failed & stayed in the harp while operating the

disconnect switch. A-phase and B-phase opened normally.

Comments

This Schwager-Wood disconnect had a history of problems, likely associated to the

instability of the ground conditions at the site. The C-phase blade was found loose,

in the harp, in a rotated position. The crank arm at the hinge end was fully rotated

in the full open position. It does not appear that the blade left the harp during

operation. (Photo unavailable for release in this report.)

Switch - In-Service FailureIncident # Incident Date Report Date Photo File Name

43910 5/16/2003 4/4/2004


Allis-Chalmers Pantograph > 500 kV 1968

Method of Detection

Cause of Failure

Mechanical failure of pantograph-type blade on the disconnect.

Comments

It has been determined that this disconnect is not needed on the system anymore due

to system configuration changes. It is scheduled to be removed. Removal of this

disconnect will allow us to have spare parts for the remaining 8 pantograph disconnects

on our system pending replacement.

Switch - Failure at TestIncident # Incident Date Report Date Photo File Name

43894 7/20/2004 8/30/2004


(No MFR Listed) EV-1 > 500 kV

Method of Detection


Cause of Failure


Comments

The equipment was a Southern States EV-1 500-kV disconnect switch. The part that


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failed was the VM-1, slave, motor operator on A-phase. When the

MOD (Motor Operated Disconnect) was operated, A-phase motor operator continued

to turn after the blade was fully open. This caused the coupling between the gear

box and the shaft connected to the rotating stack to fail. After this occurred,

the motor operator continued to spin, breaking off all open and close stops on the

motor operator. The motor operator was finally stopped when the DC control knife

switch was pulled. It was found that the 1" stainless steel gear shaft was crackedvertically.

The entire motor operator was replaced.

Transformer - In-Service FailureIncident # Incident Date Report Date Photo File Name

43917 5/17/2003 4/4/2004


Wagner Electric HAL 24 101-150 kV 1951

Method of Detection

Cause of Failure

Winding failure due to lightning.

Comments

Through Fault


43958 6/6/2003 2/23/2004


Federal Pacific Electric Transformer, LTC 101-150 kV 1968

Method of Detection

Cause of Failure

A high-current, three phase, through fault occurred and the transformer failed.

Comments

Failure caused interruption of service to 3000 customers including several large

industrials. This vintage of FPE transformer is prone to failure. We purchased

5 of these in 1968 and all five have now failed. Most of them failed during a through-fault.


43929 6/19/2003 4/1/2004


Wagner Electric 101-150 kV 1970

Method of Detection


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Cause of Failure

Poor design.

Comments

Through-fault during lightning storm (windings failed).


43908 6/20/2003 4/23/2004


Westinghouse Electric 101-150 kV 1964

Method of Detection

Cause of Failure

Possibly Lightning

CommentsHoop failure (progressive turn-to-turn fault); replaced the transformer.

Transformer - TroubleIncident # Incident Date Report Date Photo File Name

43944 7/3/2003 3/23/2004 sce2004_Rept03


Westinghouse Electric Unknown 1954

Method of Detection

Cause of Failure

Probably age related.

Comments

Contact leaf spring failed. (Photo unavailable.)


43959 7/5/2003 2/23/2004 SNPD2004_Rept02a,b,c


General Electric Transf, w LTC 101-150 kV 1975

Method of Detection

Cause of Failure

Squirrel contacted 12 kV bus on source side of circuit breaker. Corroded wiring prevented

circuit switcher from tripping. Sustained fault caused much damage

Comments

Fault started when a squirrel contacted the source side of an outdoor 12 kV breaker.


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The fault grew and involved all three-phases. Relays saw the fault properly, and

provided signal to circuit switcher to trip. Circuit switcher did not trip due

to corroded wiring inside conduit (not visible from ends). Fault and fire damage

was extensive. Two breakers and bus support structure were burned. Transformer

failed during the through-fault. Service interrupted to 5000 customers. (Photo unavailable.)


43972 7/10/2003 4/22/2004


Virginia Transformer 51-100 kV 1993

Method of Detection

Cause of Failure

Unknown

CommentsTurn to turn failure on the secondary winding. Performed complete rewinding of all coils,

testing and tank refurbishment, repair of load tap changer, installation of new remote

temperature gauges, new insulating oil, install tap changer filter unit, desiccant drier breather.


43931 8/4/2003 4/2/2004


General Electric 451-500 kV

Method of Detection

Cause of Failure

Comments

This transformer has Trench 287 kV high-voltage composite bushings.

A flashover occurred between the bottom plate and the tank wall of the transformer

and another fault between the upper part of the oil impregnated paper winding and

the flange of the composite insulator. All high-voltage bushings were replaced.


43970 8/19/2003 3/25/2004


General Electric 367 MVA 451-500 kV 1981

Method of Detection


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Cause of Failure

Lightning strike to bushing (H S bushing)

Comments

Bushing failed due to low oil level resulting in lower BIL, water had entered bushing

on top terminal gasket. Due to internal damage, replaced transformer.


43965 9/10/2003 3/2/2004


Ferranti, Ltd. Transformer LTC 101-150 kV 1995

Method of Detection

LTC was severely coked and producing high levels of ethylene.

Cause of Failure

Poor design and/or quality of LTC

CommentsProblems were uncovered during routine DGA of the tap changer oil. The first test

showed extremely high levels of ethylene, about 100 times normal. We suspected

the test was faulty, so a second sample was drawn, and it had 145,000 ppm ethylene.

The Doble lab reported this ethylene level was the highest they have ever recorded

in a DGA sample. The tap changer was maintained less than 2 years ago and has an

oil filtration unit installed. When opened up, the reversing switch had severe

coking. Movable and stationary contacts also required replacement.


43941 10/1/2003 10/22/2003


General Electric LRT-200-2 Unknown

Method of Detection

Cause of Failure

Bypass switch assembly misalignment on phase 3.

Comments

Transformer failed due to tap changer failure. Report available.


43957 10/14/2003 4/15/2004


Federal Pacific Electric 51-100 1974

Method of Detection


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Cause of Failure

Low side turn-to-turn failure.

Comments

DGA RESULTS - * The equipment condition code has been abnormal (2-3) since 08/13/2003.

The high CO2/CO ratio may indicate thermal decomposition of cellulose. Exercise

caution. Determine load dependence.


43920 11/29/2003 4/4/2004 BPAT200406


Hyundai BPA001000891 101-150 kV

Method of Detection

Cause of FailureLow voltage leads flashed over to the core.

Comments

The transformer tripped by two sets of differential, the Buchholz and the pressure relief

device operated. The 115 KV breaker at Drummond and the 161 KV breaker at Goshen

(72 miles) isolated the failed transformer within 4 cycles. The quick response from the

relays and breaker may have prevented further damage to the transformer. There were

of combustible gasses in the oil including acetylene, but the transformer tested OK

electrically. The manufacturer reported to the site within one week after the failure,

inspected the transformer and found that there was a dielectric breakdown between the

X1 C-phase and X2 B-phase leads and the core clamping structure through a lead

supporting board for X1, X2 and X3 leads. The failure occurred close to the X1 bushing

after the lead makes a 90 degrees angle from vertical to horizontal. (Photo unavailable.)


43930 1/13/2004 4/2/2004


General Electric FOA 451-500 kV

Method of Detection

Cause of Failure

Bushing Failure

Comments

Trench 230kv bushing failure caused total loss of transformer. We are replacing

all of these type composite bushings.


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43907 1/15/2004 4/23/2004 AVA2004_01


Alsthom > 500 kV 2002

Method of Detection

Cause of Failure

Comments

High voltage winding insulation failed. (Photo unavailable.)


43918 1/16/2004 4/4/2004 BPAT200407,08,09,10,11

Manufacturer Model Number KV Mfgr Year Allis-Chalmers 301-350 kV 1963

Method of Detection

Cause of Failure

Internal fault leading to winding failure.

Comments

(Photos unavailable.)

Transformer - TroubleIncident # Incident Date Report Date Photo File Name43932 2/16/2004 4/2/2004


ASEA Inc. TFTY1000 201-250 kV

Method of Detection

Cause of Failure

Internal fault caused can to split a welded seam along the lid on low-voltage side of transformer.

Comments

Unit was 8 years beyond design life, paper insulation degradation, 2300 piles driven

into ground in area for new construction, and decrease in insulation distance between

18kv internal delta bus at bottom of transformer tank.


43933 2/17/2004 4/26/2004 MID200401,02,03



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Kuhlman Electric 51-100 kV 1979

Method of Detection

Cause of Failure

Possibly due to previous over tightening of wire connection to collection ring stud.

Comments

An inspection of the LTC was made as part of the regular maintenance when the electriciannoticed the phenolic collector ring panel was burnt. The two studs passing through

the phenolic collector ring panel from the collector ring overheated causing the

board and studs to deteriorate. The 3/4" studs are reduced to 1/2" on the end connecting

to the collector ring. Solder is then sweat into the threads from the other side

(penetrating approx. 1/4"). I suspect the stud had loosened from the collector ring

(possibly due to previous over tightening) and overheated to the point the cable,

with the studs attached, came loose in the electricians hand. (Photo unavailable.)

Transformer - TroubleIncident # Incident Date Report Date Photo File Name43919 2/20/2004 4/4/2004 BPAT200421, 22


Allis-Chalmers 301-350 kV 1963

Method of Detection

Cause of Failure

Internal Fault

Comments

Winding failure. (Photo unavailable.)


43945 3/19/2004 3/23/2004 sce2004_Rept04a,b


General Electric Unknown 1951

Method of Detection

Cause of Failure

Tracking and burning of the insulating drum on NLTC allowed the conductor contact pointsto be misaligned and become loose. Severe arcing occurred.

Comments

Uneconomical to repair unit. This station is isolated load

so a generator had to be installed to off load transformer. (Photo unavailable.)


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43955 3/30/2004 4/15/2004 Sdge2004Rept10A-G.JPG


Waukesha LTC PWR XFMR 2002

Method of Detection

Cause of Failure

High moisture.

Comments

Before we put the bank in service in April of 2003 , it failed the Doble test. When

we opened it up we found severe rust all over the core. Waukesha came out and cleaned

it up and called it good. It still Doble tested bad. It started gassing so it

was taken out of service. We Doble tested it before Waukesha reps got here to see

if it was worse than the initial test; it was. The CL watts went from 1.543 to 6.619 and the

CHL watts went up to 8.250 from 1.895. We also megger tested it again to see if that

had gotten worse and it did. Low to ground was 10.7 gig ohms and now it only got89.7 meg ohms. When Waukesha drained it and opened it up on 3-21-04, the rust and

contamination looked worse than it did back in March of 2003. In March of 2003,

Waukesha drained and processed the oil for 24 hours. This was after they got inside

and cleaned up the rust off of the top of the core. The transformer came to us from

Waukesha with oil in it. The only time it was opened up when it was originally put in

service was when the factory rep was here to supervise the installation of the bushings.

Two-Winding Transformer - In-Service FailureIncident # Incident Date Report Date Photo File Name

43898 1/4/2004 9/14/2004


General Electric L252778A 1981

Method of Detection

Relay Operation

Cause of Failure


Comments

B phase (center) failure - could have been the winding insulation (most likely)

and/or the B phase HV bushing.


43889 2/4/2004 8/16/2004


General Electric GE 12/16/20 @55degC 51-100 kV 1981

Method of Detection


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Power Factor, TCG

Cause of Failure

Winding

Comments


43895 7/2/2004 9/2/2004 5230132810442451.jpg


General Electric D

Method of Detection

Exciting Current

Cause of Failure

Through-Fault

Comments

This unit has X1-X0 winding damage that showed up in TTR and excitation tests.

INTERNAL INSPECTION RESULTS

The coil structure that contains the H1-H3/X1-XO windings shows subtle evidence

that movement occurred in the structure. There are spacers in multiple areas of

the winding that have shifted out of their normal position. The LV leads that exit

the coil structure had ripped the cloth that originally tied some bracing blocks

to the leads. On one location at the bottom of the coil structure the blocking

was out of alignment. No tipping of the HV conductors or core damage could be observed.


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Two-Winding Transformer - Failure at TestIncident # Incident Date Report Date Photo File Name

43897 8/24/2004 9/9/2004


Westinghouse SL 1984

Method of Detection

Partial Discharge

Cause of Failure

Winding

Comments



ASEA-Brown Boveri SL 1997

Method of Detection

Relay Operation

Cause of Failure

Winding

Comments

reporte fallas 09-30-04

Documents