Protracted Faults In Substations

[Mbrooke]

Posted on another forum, but I want to ask here. Why does this keep happening? I mean I could see this happening (and it does) in countries where things like busbar protection were/are optional, however I can't imagine it happening to a station such as this in the US.

https://www.wral.com/no-injuries-reported-after-transformer-fire-on-nc-state-campus/19649275/

Unless its a series event, but its impossible to tell from just cell phone video.

 

[beyond86]

Main protection is failure and backup protection doesn't have enough sensitivity because of wrong calculation.
Only two reasons need to this happen.

 

[RRaghunath]

Outdoor transformers are filled with mineral oil and continue to burn even after the transformer is electrically isolated upstream. All depends on location of fault.
From my experience, a bushing fault can cause burning oil to gush out of the tank, creating the scene similar to that in the video.

 

[Mbrooke]

Thanks for the replies everyone!

 

[Palletjack]

I watched this also, and believe it’s a wrong setting in a protection relay. There doesn’t appear there ever was a “fire” at the transformer.
I’m waiting on a Duke Power report (hopefully next week) to hear their version.
The station isn’t really that old, if I’m not mistaken it’s still under construction.
Look at the video, the old trailer in this picture is in the video also.

 

[OffTap100]

That was obviously more then just burning mineral oil after the fault was isolated. That was a looooooooong fault.