Ghosts and spirits are energy- they're emotional and physical beings of energy, and to manifest or make themselves known they need power - either kind of power. For people who live near high-tension wires, they can act as a power source for the paranormal.
High-tension wires transmit bulk electrical energy at high voltages (110 kV or above) from power plants to electrical substations. These high tension wires also emit electric and magnetic fields known as EMF (which ghost hunters use to detect ghosts). Those fields can serve to "power up" paranormal activity in a home located near them (however, the home has to have a ghost in it- ghosts just aren't drawn to homes near high-tension wires).
Ghosts choose to stay in a place when people die and decide to stay Earth-bound. If they’re not in your home, it’s rare that they will come into a home (unless someone is using a Ouija board or invites them in). Spirits, however, can use that energy to come and visit their loved ones and give signs during special occasions.