Agree with winny to put the inverter next to the solar panels if possible and send 230V AC (standard in Sudan) over the clothesline, despite it being more dangerous.

If you need to transfer 1000W of power, it loses less to clotheline resistance when transferred at a higher voltage.  

1000W = 

 • 55 amps @ 18 volts 

 • 4 amps @ 230 volts

Power lost through clothesline is (Current)^2 * (Resistance). 

So chosing the lower 4 amps current (230 voltage) is much preferred. The power loss disapates as heat in the clotheline, at some point it will burn, so it's not just about efficiency, using 230V is necessary. You can probably carry 1-2kW with 1mm core wire at 230V AC. This is a microwave and some light bulbs or a couple large fans. You can try to push the draw further, but carefully observe for smoke of the insulator and shut off immediately. If this happens you need to run less equipment in the house or run more parallel lines.

Use your home-harvested copper wire for the 18V DC connection between the panels and the AC inverter.