The traditional distance protection principle based on power frequency is easy to be affected by fault characteristics of wind power system. The time domain distance protection principle based on lumped parameter model is more suitable for the outgoing line of wind power system. However, considering the principle influence of distributed capacitance is neglected, when the fault occurs in the long distance outgoing line of the wind power system, transient transcendence may occur on the distance protection instantaneous relay protection zone. Therefore, this paper presents a time domain distance protection principle for long distance outgoing line of wind power system based on distributed parameter model. Based on the distributed parameter model, it uses the voltage and current time domain information of protection installation to obtain the time domain information of voltage and current at the distance protection instantaneous relay protection zone setting which are brought into time domain fault location equation, thereby the fault distance between the whole set point and the fault point is obtained. By summing the distance of the distance protection instantaneous relay protection zone setting, fault measurement distance is obtained, achieving the protection action. Simulation results show that the principle is not affected by the distributed capacitance of long distance outgoing line, and the performance of anti-transition resistance is good. The protection performance is superior to the time domain distance protection based on the lumped parameter model. This work is supported by National Natural Science Foundation of China (No.51467019).