Characterization of AC Fault Rejection Induced Phase Change Failure and Suppression Strategy

In practical engineering and simulation studies, it has been found that DC transmission phase change failure exists during AC fault removal, which worsens the recovery performance of the system, and even leads to DC blocking in severe cases. Firstly, the mechanism of phase change failure during AC fault removal is analyzed, and it is found that phase shift of phase change voltage and high DC current level are the main factors of phase change failure; then, the effects of AC fault and fault duration on phase change failure are investigated on this basis; finally, based on the evaluation of the phase change area, an improvement strategy for suppressing the phase change failure during fault removal is proposed, and based on C Finally, an improved strategy for suppressing phase change failure during fault removal is proposed based on the evaluation of phase change area and simulated based on IGRE HVDC standard test model. And the simulation results show that the proposed strategy can effectively suppress the occurrence of phase change failure during fault removal. The results show that the proposed strategy can effectively inhibit the occurrence of phase change failure during fault removal. The conclusions of the study can provide ideas for the suppression strategy of phase change failure during fault removal.