Commutation failure starting value setting method and device

The invention discloses a commutation failure starting value setting method and device, belongs to the field of safety and stability analysis and control of an electric power system, and provides the commutation failure starting value setting method and device aiming at the problem that commutation failure prediction control starting value setting of a direct current system is not high in adaptability. According to the method, the severity of the direct-current system fault is determined by detecting the maximum values of zero-sequence voltage and three-phase voltage changed by alpha and beta in the first period after the fault, and the obtained voltage amplitude in the first period after the fault serves as a reference and is multiplied by a certain coefficient to serve as a commutation failure prediction control starting value. Therefore, the commutation failure prediction control starting value can be adaptively set in different fault scenes. Simulation results show that the commutation failure prediction control starting value can be effectively set, and compared with an existing method, the commutation failure suppression effect is improved to a certain extent.