I have a 5' easement for power line to my house. They will occasionally prune if the trees get within about 5' of power line. The only time there would be an issue, likely, would be if the pole needs replacing. They have even replaced my power line drop once without bothering my trees.
If you have power lines that service more than just you house, there might be more issues. It depends on how difficult it would be to replaces the poles/lines that run through the easement and what the likelihood of that needing to happen is. If there are no actual wires or poles across your property, it may be an abandoned easement or one that was never used.