Protracted Arcing In Substation 2

[Mbrooke]

Video of what looks like arcing at a Con Edison substation, possibly East 13th st:

https://www.reddit.com/r/SubstationTechnician/comments/h9d07n/no_no_no/

From my vantage point it looks like a series arc on a 69 or 138kv disconnect switch. My question is- why didn't relaying catch it? I'm assuming differential protection is present.

 

[Mbrooke]

Any electrical emojis? Not really an emoji- but its on my hard drive

 

[davidbeach]

Series arc or the much more common shunt arc? Given the blackout, I'd say it was a shunt arc. Easy to find and clear without taking out more than necessary.

 

[Mbrooke]

From what I was told about the above GIF was that an overhead splice broke (notice the lights dimming at first due to the delta-grounded wye transformer losing a phase) with the falling conductor striking other phases causing the feeder to trip altogether.