ECN Forum Forums General Topics of the Trade General Discussion Area Incredible Video of Powerlines Out of Control!!

Increadible video footage.
I'm amazed that the utility crew did not contact the POCO control room via cellphone or RT and told them to drop the feeder concerned, cut away the fault and reliven the healthy section.
It looks definitely a good HV to LV fault burning through the transformer primary and secondary windings and at later stages the HV supply finding a path through the neutral and earth conductors from the houses affected.
It is interesting that the OH cables don't burn themselves clear from the actual fault within the heat of the arc.
At 3:52 somehow the gutters become path of the fault current as well, could be copper downpipes providing additional return path to ground.
The firemen appear vey casual about the overall incident and don't seem to be aware of stepvoltages and stay very close near the smoking house prior to the spouting starting to arc.
This is definitely a faillure of the Earth fault protection relay on the HV supply.
The overcurrent may not always operate because it may be a long line and the resistance within the arc may not enough to trip the relay on OC.

These cases do happen. I posted last year under photo's about 11 kV lines in te atatu.
We had a charger failed in a sub under rebuilt, alarms not working and lines burning holes in a concrete driveway.
I was first on site. told control to drop the feeder concerned, open nearest ABS and reliven the healthy part of the line.

Am I right to understand that this condition was allowed to exist for hours? The risk to life and property caused by allowing this to continue is absolutely unacceptable... I certainly hope the power company was held responsible for all the property damage!

Our local power company (Portland General Electric) has cutouts on the HV at every transformer and junction... Understanding that their response may not be quick enough to save life/property, the fire department supervisors have been provided with hotsticks and the necessary training to open the cutouts if necessary.

noderaser:

Yes indeed, that is correct. According to the comments from the person who posted the video, the situation was allowed to continue unabated for several hours.

I hope that someone who sees the video and was perhaps either there or working for the POCO at the time can offer up some sort of explanation for the length of time this was allowed to continue.

To quote Rodalco's post:

and



But I wonder if here in the US, the POCOs use earth fault relaying?

No matter what, I agree the POCO was unacceptably negligent in this case.

But this thought is kinda scary too:



Wow. Given the possibly long interval between training and having to open a cutout under fault conditions, I wonder how wise that really is....

Generally, they do this when a building fire is being caused by electrical means not easily disconnected from the building, or if a safety hazard would be present by leaving power on to a building. If a condition like the one in the video existed, I'm sure they would go "upstream" of the problem a safe distance and open a cutout. Of course, this is all done only if the power company isn't able to respond in a timely fashion, to minimize the risk to life and property.

These days, I'm sure that solving such a problem would be as easy as calling the distribution office, and having them shut down the neighborhood.

...yeah, when the genie gets out, all you want to do is run like hells door just opened