An Emergency Control Strategy of Synchronous Condenser to Reduce the Risk of HVDC Continuous Commutation Failure

During the commutation failure and its dynamic recovery process, the voltage fluctuation caused by the frequent reactive power exchange between the HVDC system and the receiving-end AC system is one of the important reasons for the continuous commutation failure. Large-capacity synchronous condenser is equipped with strong transient voltage support capabilities, which is important means to reduce the risk of continuous commutation failure. This paper analyzes the effect of the conventional control method of the synchronous condenser to deal with the continuous commutation failure, then based on its response characteristics and HVDC recovery characteristics, an emergency control strategy of the synchronous condenser is proposed. Firstly, control the synchronous condenser to the strong excitation according to commutation state. Secondly, adopting the commutation failure prediction to maintain the strong excitation control. Finally, exiting the strong excitation control with a constant slope control. This method can improve the stability of the commutation voltage and reduce the risk of continuous commutation failure. At last, Based on JingSu DC of the East China Power Grid, the effectiveness of the emergency control strategy is verified with electromechanical transient simulation software PSDEdit.