The power company is not allowed to transmit from their lines. They must fix any transformer or connection that is transmitting. Every power company is required by the FCC to have the capability to detect and repair any line that is causing interference. You can find more information about power line interference at www.arrl.org . Just search on interference.
Also you may want to orient the antennas to horizontal polarization, to reduce interference from other band users.
Good luck.