Abstract:The commutation failure of high voltage direct current (HVDC) transmission system has a huge power impact on the AC system. It is necessary to accurately detect the commutation failure of the HVDC to take targeted safety and stability control measures. At present, the stability control device which has already been used in engineering identifies the commutation failure of HVDC depending on the signal of DC control and protection system. When DC control system crashes or the channel with stability control device is abnormal, the stability control device dose not operate correctly. The characteristics of electrical quantities under the condition of DC commutation failure and its identification principle are studied, while the criteria and applicability of DC control and protection system commutation failure protection are introduced. Then, the criteria of commutation failure, continuous commutation failure and multi DC simultaneous commutation failure identification are put forward, which are suitable for safety and stability control. The real time digital system (RTDS) test results based on the actual control and protection system of Bin-Jin HVDC show that the proposed criteria can accurately judge the commutation failure of DC system, the frequency and time interval of continuous commutation failure according to the requirements of safety and stability control.