Unless the power lines are generating frequencies in the 2.4ghz and/or 5.8ghz bands, then there shouldn't be a problem with the drones being around them. Now there could be a danger in that the drone could actually physically contact a line and break a propeller, which would certainly lead to it tumbling down to the ground. And I have seen at least one video where a drone contacted a power line and sparks flew from the contact, so apparently that is a risk as well.
I believe each drone gets mated to it's specific controller, and apparently this is a narrow enough band that interference isn't often an issue. I have a wireless network set up at my house with repeaters that allow me to connect to some equipment in a building 150 ft. away. And I have wireless cameras set up, with two of the transmitters right on the garage in the video. There are four wireless cameras total, each with their own specific frequency. None of these signals have interfered with any of the drones I have been flying. And that doesn't even take into consideration all of the other bands of radio frequencies that I am sure are all over the place.
I think if these sorts of things were a substantial problem, all of the radio controlled devices would be rendered pretty much useless unless used way out in the boonies where there would be absolutely no interference at all.
Personally I wouldn't fly around power transmission towers at all, if for nothing else, the possibility of physical contact with all the lines involved and the fact that they will be VERY difficult to tell exactly how far away from the drone they really are. Proximity determination at long distance can be deceiving. Using FPV (first person viewing) is not going to be much help because of the narrow view and the fact that nearly all of the cameras use such a wide angled lens, that distances can be very difficult to determine. The best course of action from what I have seen is to always move ONLY in the direction the camera is pointing if you are anywhere near any sort of obstruction.
YouTube is chock full of drone crashes, and I've been watching as many as I can just to see what the most common causes of crashes are. Nearly all of them, especially lately, appear to be from pilot error. Either from mismanagement of the controls in a panic situation, or else just not paying attention to what is around the drone and especially in the direction it is heading, not where it is looking.
Probably one of the most problematical situations I have seen that crashes a drone is when some stupid bird attacks it and they both likely don't fare well after that encounter. I don't know of any way to avoid that if it happens, because unless the bird comes at the drone from the camera's point of view, you would never know what hit the drone to bring it down. Even seeing a bird coming, I don't think my reflexes would be faster than the bird's anyway.
Now that being said, I have found that the compass on this new drone is VERY sensitive to interference, especially magnetic in nature. When I was playing around with trying to calibrate the gimbal, I was using a battery powered level and I found that every time I put it near the drone, the controller would tell me that there was compass interference, and refuse to allow me to launch the drone. And I have heard of people having problems when especially strong magnetic solar storms were taking place.
FYI, I found a particularly interesting site that shows a lot of pertinent data concerning environmental factors that could affect flying radio controlled devices, and shows them all in a real easy to read format, along with a recommendation as to whether it is actually safe to fly a drone or not at any given time.
https://www.uavforecast.com/#/
Hopefully I'll get to fly the drone again tomorrow. Supposed to be cloudy all day, but winds should be calm. Got two additional batteries I ordered finally, so I'll be able to charge them up and able to fly for a longer period of time. Not sure I have the confidence level yet to send the drone out over the woods over my property, but maybe. I might try to fly it above the house to see how that goes. Baby steps, I guess, until I'm sure of myself and this equipment.