Analysis and prevention of commutation failure caused by HVDC rectifier AC faults

Abstract

Abstract Earlier works have reported that rectifier AC faults also can cause commutation failure during fault‐off recovery process. Whereas the occurrence of CF is merely ascribed to inverter AC faults in conventional wisdom. Note that the existing CF mitigation approaches are designed mostly by the evolution of inverter electrical quantities, which will fail to take action to CF caused by rectifier faults, posing threat to the operation of power system. Thus, the paper firstly presents the essential reasons for CF caused by rectifier ac faults, combined with the fault information transmission process and control response. It is found that DC current surge and improper control interaction are the main reasons. Accordingly, a novel current cooperative optimization (CCO) control strategy is proposed, which aimed at reducing the risk of CF caused by rectifier ac faults. Simulation results verify the correctness of the mechanism and the effectiveness of the proposed control strategy.