Online emergency control and corrective control coordination strategy for UHVDC blocking faults

UHV AC/DC hybrid power grid with strong DC and weak AC characteristics will bring severe impact on the receiving end power grid in the event of DC blocking. In order to improve fine control level of UHVDC blocking, this paper studies online coordination and optimization methods of various control measures including emergency DC power support, pumped storage control and accurate load shedding in the existing frequency emergency coordination control system from two aspects of emergency control and corrective control. Considering the overload problem of transmission sections caused by online pre-decision of emergency control, as well as priority and costs of control measures, the strategy is adjusted by DC power flow calculation and AC power flow check, using distributed parallel cluster algorithm. Based on the actual power grid model, the proposed control strategies after the occurrence of UHVDC bipolar block fault were simulated to verify the effectiveness of the online emergency control plus corrective control decision.