BREAKER POLE SHATTERING ONE AFTER THE OTHER. 1

[kelvesfans]

Good day my fellow engineers, i must acknowledge the good work you all are doing here, i am new to this forum, i have a serious issue with our secondary breaker to a feeder,the circuit breaker pole started shattering one after the other from red, yellow to the blue phase, the transformer is a 60MVA transformer please anyone have clue as to solving this issue? any other details can be posted if needed. thanks

 

[waross]

Uh Type of breaker? Voltages? Relay history? Over current? Fault? Lightning? Switching? Line transients? Spontaneous failure?

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[kelvesfans]

TYPE OF BREAKER : SCHNEIDER ELECTRICS, SF6 BREAKER. VOLTAGE:33KV RELAY HISTORY (MICOM P122) VERY RELIABLE,600/1 SETTINGS SPONTANEOUS FAILURE , STARTED SHATTERING ABOUT 1 MONTH INTERVAL FOR ALL THE PHASES

 

[ScottyUK]

Does your employer have access to the British NEDeRS database ? It's a useful tool, especially if you suspect there is a possible type defect with which the manufacturers aren't being forthcoming. If you have access then you can look up the specifics of your equipment and see what operational history it has. Note that I am not suggesting that this is a type defect, but just highlighting the existence of this useful organisation.

This failure sounds fairly serious so I would expect that Schneider would be interested, if only to clear their name. Their technical support people would be my first call. My first guess is that there is an installation / workmanship problem.

 

[EngAust]

What are you trying to switch?

 

[DTR2011]

When does the shatter occur? Is any switching (open or close) occurring?




If the problem occurs during a switching (or relay), this may also be indicative of poor adjustment of the mechanism (overtravel / rebound). Were the breakers tested in the field (timing / travel)? Do you have copies of the factory test data?

 

[kelvesfans]

@ smallgreek, the breaker was in circuit closed position,the shattering do occur at night,and then the relay didnt discriminates the fault even when the conductor from the CT was pulled to the ground, i will sort for a copy of the field data test and get back to this wonderful forum, i want to use this medium to say thank you to all of you that have assisted in one way or the other, and those of you that are yet to comment,and also to the owners of the site

 

[DTR2011]

This sounds like the porcelain bushing is failing (shattering).. Is that correct?

I was thinking it was mechanism related. If the breaker was sitting closed and no fault occurred.

Is this an outdoor breaker in an air insulated substation?

 

[ScottyUK]

Where are you located? Could it be due to human interference?

As a youngster I can recall trying to shoot OHL insulators with an air rifle without really being aware of the danger or the chaos which would have resulted. We were terrible shots anyway, so we gave up and went back to shooting drink cans. As this seems to be a recurring problem I wonder if you could have any locals taking a shot with something of slightly larger calibre? I think it would take a fairly powerful shot to fracture an SF6 breaker, but I haven't tried it (yet).

 

[Skogsgurra]

Never, ever aim at breaker poles! Beer cans are a much better target.

http://www.gke.org/pub/files/Beer can hit by shot 1.AVI

Gunnar Englund

http://www.gke.org

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Half full - Half empty? I don't mind. It's what in it that counts.