CT explosion 2

[VikingUK]

Just had visit from electric transmission company. He wants to erect a wall around our transformer compound to protect personnel. They have had 2 instances of the porcelain 132 CT exploding and need to replace all of them right across the country (big job). Anyone heard of this problem ?
Sorry I am not electrical so 132 CT is the best description I can give but I mean the porcelain things on top of the high tension transmission cables.

 

[ScottyUK]

The problem affects type FMJL current transformers made by GEC, and they are not exclusively 132kV devices. The attachment was issued by NGC folowing the event.


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

 

[cranky108]

It's not unheard of for porcelain products to fail violently. Usually it is because the seal fails and water enters the device.

 

[racookpe1978]

OK - So my crew (me!) are regularly working on de-energized turbines/generators/isolated transformers at power plants during outages.

I don't recognize the terms though - reasonable, since I''m not distribution-qualified nor trained.

Should I pass along additional "Keep Away = Do Not Disturb" warnings to the millwrights/machinists working near isolated generators until these barriers are in place?

 

[cranky108]

There is always a risk of exploding equipment inside substations. That is a reason why substations are typically large with fences around them.

It is also common to place walls between transformers to reduce the risk of loosing more than one transformer from a single event, or fire.

Actually we are looking at replacing several PT's because the rubber on several units has cracked and cought fire from the years in the sun.

 

[VikingUK]

ScottyUK.. thanks... thats the one that is afecting my sub station.. they are coming to put protection around it.

 

[ScottyUK]

Yeah, just let them build the wall: better than trying to remove a 10lb chunk of porcelain from your head.

I think one of the proposals was to use double-stacked shipping containers as a quick and dirty answer to providing a blast wall but I guess that will not be a solution which fits in every location.


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

 

[VikingUK]

Yep.. thats what they want to do here.. Ive told them the hazards involved in stacking containers is greater than the potential hazard of a porcelain explosion (very windy here) also Ive asked for guarantees of compensation if they break anything and shut us down

 

[alanlawand]

Usually the CT get explosion if the secondary winding (s) is (are) open. Otherwise it will not get explosion.