Breaker Failure 1

[EngAriz]

Hello,
Kindly can any one give some information about what causing 132kv Transformer Breaker to Fail In the 132/33/11kV substation.

Thanks,

 

[desertfox]

hi EngAriz

Can you give any information leading upto the failure and what failure as occurred.

desertfox

 

[alehman]

Sorry, but that's akin to asking "My car has quit working. Can you tell me why?" More details, please!

Alan
“The engineer's first problem in any design situation is to discover what the problem really is.” Unk.

 

[odlanor]

Circuit Breaker failure results from 2 kind of failures:
1-Failure of CB to open ( stuck breaker)
CB with failure does not opened mechanically. You can detect this by sinalization of springs loaded or by CB auxiliary contact closed.
2– CB opened mechanically , but was not opening electrically. (arc voltaic was not interrupted.)
CB failure opened but you can verify circulating current due to not interruption of electrical arc , internally, between main contacts of same pole of CB.

 

[pwrengrds]

Loss of SF6 gas pressure.
Loss of SF6 would stop the breaker from opening electrically. It would also explain why the breaker would open but not break the arc.

 

[ScottyUK]

How do you know it is an SF6 type?


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If we learn from our mistakes I'm getting a great education!

 

[marks1080]

A SF6 breaker with a loss of pressure would not open.

 

[pwrengrds]

I don't know its SF6, but at 132kV it's a real good bet.

 

[ScottyUK]

You should see how much bulk oil and air blast 132kV stuff is in the UK. SF6 is slowly replacing these older types but there are a lot of legacy breakers out there.


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If we learn from our mistakes I'm getting a great education!

 

[marks1080]

i would bet oil and air outnumber sf6 in N.A. as well. Slowly being replaced with SF6...

Elements rarely get replaced when they are still in good working order. Those old oil breakers made in the 40s and 50s are almost indestructable.

 

[odlanor]

In my utility SF6 breaker loss of pressure initiate Breaker Failure Protection. After Breaker Failure is Blocking initiates open of isolator switches of CB with loss of pressure. So you can restablish circuits with CB with damage completely isolated.

 

[cuky2000]

Per IEEE reference, the circuit breaker failure modes are basically two types: 1) failure to Trip & 2) failure to clear
1)Failure to Trip could occur because the contacts do not open after trip circuit energized, short or open in the trip coil or mechanical problem with breaker.
2) Failure to Clear may occur when contacts open but fault not extinguished. Also, the current continues to flow or a combination of mechanical or dielectric problems.

 

[alehman]

It would be really nice to hear back from the OP.

Alan
“The engineer's first problem in any design situation is to discover what the problem really is.” Unk.

 

[EngAriz]

All,

Thanks for the imformation, it's very valuable.

Thanks

 

[m3ntosan]

odlanor,

Why trip all circuits connected to a busbar by BFP? Why not leave BFP to operate when there's actually a fault and the CB fails to open?

Isn't an option to leave the CB blocked in "Close" position until the System Operator does some switching in order to isolate the problematic CB?