A Novel Capacitive DC Transformer for Adapts the DC Voltage Levels in DC Power Systems

Direct current (DC) transmission power system has characteristics that make it an alternative for the conventional alternating current (AC) power system, the only difficulty in the existing DC system is to obtain high voltage DC (HVDC) from low voltage DC (LVDC) and LVDC from HVDC directly. Based on the mutual capacitor phenomenon, this paper presents a novel capacitive DC transformer for step-up or step-down the DC voltage magnitudes. The operating principles of the proposed transformer are presented, followed by detailed mathematical analysis of the proposed transformer concepts. Based on the proposed transformer concepts, full-scale simulation of a 600MW, 500kV DC power system has been designed and tested for managing electrical energy between two DC power systems at LVDC via the HVDC link.