Robot plugging in itself

I am looking for solutions about devices that plug themselves in a charging station.
The scenario is this:

In a vast yard, on a aerial wire, a device hangs and can be controlled remotely. The device would move along the wire, similarly to a chairlift. Once in a while it should get back to a charging station.

Any suggestions for such charging station and charging method?

Grounded aerial wire, metal body to device, wire brushes at charging station

"Any suggestions for such charging station and charging method?"

In its simplest form the bot might move to a position where two charging wires on the bot touch two charging wires from the charging source.