Loss Comparison Study of MMC-HVDC and All-DC Offshore Wind farm

This paper made comparative system loss research in MMC-HVDC and all-DC offshore wind farm. Firstly, structure of the two wind farms is introduced where all-DC type is based on modular isolated DC/DC converters (MIDC). Then system loss is classified. As wind speed is random and unstable in actual offshore wind farm, average loss is defined and its calculation method is proposed in this paper. Both system loss and electronic device number are calculated. Results show that average loss in MMC-HVDC wind farm is 4.0%, while 2.12% in all-DC wind farm. The number of IGBTs used in all-DC wind farm is much less than that in MMC-HVDC wind farm, which contributes to improve system reliability and economy.