If commutation failure does not occur when single-phase high resistance grounded in single-circuit AC line of inverter,then single-phase circuit breaker tripping may lead to commutation failure. Firstly,the expression of converter bus voltage after single-phase circuit breaker trip is derived by using symmetrical component method. Based on the expression,the main factors affecting the converter bus voltage are analyzed,and it is found that it is related to the equivalent parameters of the system. Then,the influence mechanism of voltage deviation angle of commutator bus on extinction angle is studied. It is found that the zero-crossing forward angle of commutation bus voltage after the single-phase breaker trips is the main factor leading to the decrease of the extinction angle,and commutation failure will be induced in serious cases. Finally,the AC/DC simulation model was built on the PSCAD/EMTDC electromagnetic transient simulation software platform. The simulation verifies the effect of the tripping of single-phase breaker in single-circuit AC line on the commutation process of inverter. The simulation results are consistent with the theoretical analysis.