Our customers are telling us they use HVDC Converters in conjunction with low cost Direct Burial outdoor lighting cable (which they have found is ideal for use at 5KV DC) for short range electrical power transmission.  The very thick black PVC insulation over top of #16AWG conductors makes for virtually lossless transmission (0.1% power loss per kilometer).

http://www.amazon.com/gp/product/B000VYIDGI/ref=noref?ie=UTF8&s=hi&psc=1