Abstract: The asymmetry of channel delay will affect the time synchronization accuracy of line current differential protection and reduce the reliability of protection action.It is necessary to conduct an in-depth study on the mechanism of the impact of disoperation and misoperation to improve the overall reliability of line protection.Firstly,according to the basic principle of line current differential protection and time synchronization mode,the reasons of protection disoperation and misoperation caused by asymmetric channel delay were analyzed.Then,the probability models of disoperation and misoperation induced by asymmetric channel delay were given,and the corresponding algorithms were designed.Finally,five scenarios of line protection were taken as examples to verify the feasibility and effectiveness of the algorithm.The different characteristics of disopetation probability and misoperation probability under the same asymmetric channel delay probability distribution function were studied quantitatively.The research results have reference value for the optimal configuration and the selection of protection strategies of relay protection channels.