Analysis and Solution of Commutation Failure Caused by Abnormal AC Voltage Measurement in HVDC

Based on the two UHVDC transmission projects of China Southern Power Grid, the event of abnormal AC voltage measurement on the inverter side is introduced. The phenomenon of commutation failure after abnormal AC voltage measurement in the event is analyzed in detail. It is concluded that the reason of commutation failure is the abnormal firing pulse caused by the abnormal voltage measurement after the power supply of the voltage measuring device, which is confirmed by the real-time simulation hardware in the loop platform simulation test. Finally, a solution to the optimization of switching system logic and PLL AC fault latching frequency strategy after abnormal AC voltage measurement is proposed. The simulation test and on-site test verify the effectiveness of the proposed scheme