Use a mains transformer & then use standard elec fence wire (not poly rope) to take it via insulated fixings to the field you need the power in. Most mains ones will do miles of wire. We have one unit that does 2 pig fields (lots of multi height wires) & 6 other fields (single strand on top of post) too. I use blue water pipe dug into the ground & "lead out" cable to go under gate ways. I can then run wires across each field from side to side to strip graze the field (this is for cattle but would work well for horses too).
Justme
Justme