Topology and parameter design of power quality control device for medium voltage distribution network

Power quality control device for medium voltage distribution network with source-load isolation is presented in this paper. It can solve many power quality problems, such as frequency fluctuation, voltage fluctuation, voltage flicker, voltage sag, short-term voltage, three-phase unbalance, harmonics, intermittent wave, temporary overvoltage and so on. It does not need to detect power quality events, and can realize seamless switching between grid side power supply and energy storage power supply when voltage sag and voltage short interruption, ensuring uninterrupted high quality power supply on the load side. A parameter design method considering redundancy of cascaded H-bridge is proposed, and a set of 1MVA power quality control device for medium voltage distribution network is developed. Experiments verify the effectiveness of the device parameter design method and the power quality management performance. An effective method for comprehensive improvement of power quality in distribution network is proposed.