There was a study counting the number of people who lived next to power lines and had cancer, and stated that there were a lot of people with cancer. But there was no control experiment done counting those with cancer who were not by power lines, which renders the study worthless. After all, the number of people with cancer is high anyway.
In my opinion, there is no excessive risk posed by the power lines that you won’t encounter anywhere else. The dye in cola drinks, for example, is carcinogenic and is consumed by millions. We power our cars with stuff that causes cancer. Don’t worry too much.