Lack of investment in LA resource management, is the only CAUSE. Playing the blame game will not fix anything.
Lawyers suing Edison allege that a Jan. 7 power surge on a nearby, active line created a magnetic field that briefly re-energized the dormant cable, setting off the sparks that ignited the blaze.
So the line in question wasn’t energized. I’d be curious how much current would need to flow in a nearby energized line to induce enough current in the idle line. Depends on the distance, but the required current would probably need to be on the order of kiloamperes.
Yeah, not even plausible. The lines I build to handle kA are still beefy, and that’s just for pulsed operation. Steady state, that’s a busbar.
My first reaction is also pretty skeptical. That said, while the article was written by someone not really in the industry it is an interesting question. We know normal line operations create mutual inductances…I think if there were a dead line that temporarily shared a ROW or even a tower with an energized line could be subject to this. Esp during a fault on the energized line.
Basically, I think it’s unlikely but it’s definitely not impossible and is probably worth looking into
I’m on the r&d side of this kind of stuff, so no idea what NFPA et al say about unused lines, but I’d be surprised if the unused line wasn’t physically disconnected via vacuum breaker or something, particularly in a locked out state.
That said, an investigation shouldn’t take much time or expense. Was the line locked out?
Inductance has a linear relationship with distance, so it’s possible something happened, but… Unlikely.
Yeah my assumption would be that it was open on both sides, otherwise it wouldn’t be deenergized. But that doesn’t mean you can’t get induced current flow. Let’s say our dead line shares a tower with a high voltage live line. Our dead line has multiple ground connections via undergrowth. The live line experiences a line to ground fault, creating high currents in its faulted phase but also a ground potential rise at the fault location. So now our dead line is experiencing possible potential differences between its many ground locations as well as induced current. This current would be inherently directed to the lower potential ground which in this case is likely via a tree branch. I don’t think it would take much current or much time for that to create a fire.
Again, I don’t think any of this is particularly likely, but I don’t think it’s out of the question either. At the very least it’s the kind of question industry should always be asking itself
A lot hinges on undergrowth making shorts, but as I’ve heard it, any tower is required to keep undergrowth from doing that kind of thing.
Look, anything is possible. But pragmatically speaking, if you’ve got a pylon with a dead line and a live one, may as well take care of both lines’ clearance. I hear what you’re saying, it’d just be mind bogglingly stupid.
