There's only one way you're going to find that out for definite... the hard way and for yourself.
From personal experience, I've had a Mavic 2 go haywire twice when launched near a HT pylon. Both times it displayed a violent yaw error and headed...
It does.
At what distance is a calculus of factors.
For instance, as a child, my middle school had high tension lines going across the school property.
When it was really foggy, we could get fluorescent tubes, and they would light up when we...
I think this is a good time to note that, while a drone wasn't responsible, the devastating Maui fire a while back was caused by a power line coming down.
Stay away from power lines.