Do power companies know where downed lines are?

We had a pretty good snow storm here last Thursday and Friday, and as a result we lost power for almost 2 days. The obvious problems were downed trees falling on power lines, as it was a very wet and heavy snow. Being in rural Maine, this is not uncommon. I called the power company, and they did know about it, as I suspected. But that got me wondering: How exactly do they know? Will they know if my area loses power if nobody calls them? Also, do they have any idea of where the problem is, or do they have to actually trace the lines visually?

Anyone know?

When I was growing up, we used to lose power regularly, and we always called the utility. Sometimes they knew, but sometimes it was news to them. So I assume that they count on calls from customers to let them know the extent of the outage.

It seems to me, they can tell that a line is down, but not where it is down. I doubt 10 or so (neighborhood streets worth) houses would ALL turn off ALL of their devices at once.

They might use a TDR (time delay reflectometer) on the cables from the plant. A TDR works by sending an electrical pulse down the cable. If there’s a flaw or break in the cable, some of the pulse bounces back. They can then tell not only where the flaw in the cable is, but also the nature of the flaw. Complete breaks, incomplete breaks, grounds, and water in the cable all have their own TDR signature.

Thanks. So the technology exists, but power companies may or may not be using it. One thing I was wondering, was whether or not they know if they’ve fixed the problem. That is, if a repair crew finds a downed line and repairs it, how do they know if there are other breaks in the line. It sounds as if this TDR would let the plant know immediately, and they could keep directing the crews as needed.

The most common fault location source to a utility is the incoming call from those in the dark,or alert policemen on road duty[wires down etc].

These serve to locate the area effected.

Some feeders have sectionalizing interrupters which will limit the the outage to a section of line,

However,if the Fault is in the first section leaving the substation the entire feeder will be our of service.

The latter situation again falls to the incoming call and the feeder map which shows the area being fed,street -by-street.

Since most feeders are still overhead,and faults are so variable,it’s rare to be able to pinpoint a fault .

There ARE fault finders,yes, but there efficiency is much less than the call from the frantic lady with a roast in the oven and her mother-in law in the living room.