The Analysis of AC Faults in AC/DC Hybrid Distribution System with SOP

AC/DC hybrid distribution system becomes increasingly necessary for integration of distributed renewable energy resources (DER) and management of carbon emissions. However, the fault characteristics of AC/DC hybrid power distribution network are vastly different from traditional AC distribution system for their varied structures. Considering the strong capability in controlling power flow and fault current of soft open point (SOP), this paper establishes the model of AC fault sequence network of hybrid distribution system with SOP, in which positive and negative separation control strategy is adopted by the converter. The model includes traditional AC equivalent network, DC equivalent network, back-to-back converter and its control system, based on which the AC fault characteristics in AC/DC hybrid distribution system are analyzed. Through utilizing PSCAD/EMTDC, different simulation scenarios are carried out to verify the effectiveness of AC fault modeling and analysis method of AC/DC hybrid power distribution system with SOP, thus providing a theoretical basis for AC side protection scheme of AC/DC hybrid system.