Simulation Analysis on the Commutation Failure and Power Recovery Characteristic of an Actual DC Transmission System

In order to evaluate the security and stability of AC/DC hybrid power systems,it is necessary to explore the interaction between the DC transmission systems and the embedded AC system during commutation failure and DC power recovery.By using a real-time simulaton tool,which can precisely simulate the DC main circuit and its control and protection system,and taking an actual HVDC system in China Southern Power Grid as a test case,this paper evalutes the influence factors on the occurrence of commutation failure of inveter after AC system faults.The results show that the magnitude of three-phase or single-phase voltage drop is the key factor for the occurrence of commutation failure of DC system after three-phase or single-phase to ground faults occur.