The best place to get the correct answer to how close power lines can be to your deck or even your house might be found at your local building department.
It sounds however like this is a low level line coming into your house from the power line poles off your property. If so, there probably isn't much you can do about altering that inexpensively.
But I do not know what the health issues are about line kind of power line. If there is an electrician reading this perhaps they might add a comment or two to help out.
Hi, can you advise the estimated life of a Titan Deck Foot installed in the ground? How long is it expected to last? I live in an area in Ontario Canada