On Wednesday, the QRN was gone for a few hours in the middle of the day, and I figured that maybe they'd found and fixed the problem on their own, but it was back by the afternoon. Yesterday, the power company officially announced that all customers were back in service, so I figured that I'd give them a call today to see what they'd say.
The automated voice response system had no way to understand "RFI" so it thought I was reporting an outage, and because that's not the case, I finally got through to a human ... who seemed equally baffled. I explained that I was an amateur radio operator and that I was hearing electrical noise that I hadn't heard until about a week ago. He put me on hold for about 10 minutes and when he came out he said they'd be dispatching a crew.
While the recommendations for a situation like this are to try to narrow it down to a small area or even a single pole, in additional to not really having the right kind of DFing equipment for this, I'm home tending to one of my kids who is recovering from minor surgery, so I didn't want to spend the time walking or driving around. I am crossing my fingers that PSE&G (my power company) will take this seriously enough to send out a properly equipped crew and find the problem. I'll be keeping my fingers crossed.
Here's a short video that I took showing what the powerline noise looks like: