Comparison between the electrical capabilities of the cables used in LV AC and DC power lines

The need of a high quality of the electricity supply has induced many customers to equip their plants with appliances (UPS) that have inside a DC section in which it is inserted a storage system. Moreover the technological progress has recently made available on the market various small power generators (in the order of the tens of kW) that often generate electricity in direct current. Therefore it is possible to think to integrate some loads and generators by means of a local DC distribution system interfaced with the public distribution network by means of an inverter. This substantial modification will involve new strategies concerning the control and protection philosophies for the new distribution systems and also for load and distributed generators. In this paper it will be considered the use of a DC low voltage local network; in particular, under the hypothesis to employ the existing LV AC cables, a comparison concerning losses and transmissible power between AC and DC distribution scenario is performed.