Efficiency analysis of low- and medium- voltage DC distribution systems

In this paper, sustainability aspects connected to the use of dc for power delivery in low- and medium-voltage distribution systems are treated. The efficiency of an example AC system, a DC system and a mixed AC-DC system are calculated and compared. It is shown that, under the assumption of a substantial reduction in semiconductor losses, the total system losses decrease using DC. This means that for the same energy delivered, less energy must be produced from the available sources, thereby indirectly reducing the environmental impact of energy production. Moreover, the DC system seems to lead to better utilization of the HV/MV transformer, so that the same system can be expanded to supply a higher load without changing the transformer.