Abstract: The influence of excessive resistance on three-stage distance protection is particularly obvious in the 110kV network incorporated by photovoltaic power stations, resulting in the low accuracy of line distance protection action in the 110kV system of photovoltaic grid connection. The reason is that the tilt angle of the transition resistance will change when the light intensity changes, causing large errors. Through simulation, it can be found that the accuracy error of traditional distance protection can reach 19% when photovoltaic grid connected is grounded through a large transition resistance. To solve this problem, this paper proposes an adaptive distance protection strategy that changes with the tilt angle of transition resistance in photovoltaic grid connection. First, through the fault component analysis, the inclination angle of the transition resistance is completely determined by the equivalent impedance of the photovoltaic power station. Secondly, it is found that there is a certain functional relationship between the equivalent impedance of photovoltaic power station and its power generation. Thirdly, after finding the relationship between and, the relationship between the measurement impedance error caused by the change of transition resistance inclination angle and the power generation of photovoltaic power station is obtained. Finally, through this relationship, a new criterion of distance protection action is given to guide the action of three-stage distance protection. Through PSCAD simulation analysis, the error accuracy of the simulation results of the adaptive distance protection algorithm that changes with the inclination angle of the transition resistance under various working conditions is significantly higher than that of the traditional distance protection algorithm, and with the larger PV processing P, the closer the fault point is to the protection installation, the larger the transition resistance is, the more obvious the advantage of the adaptive distance protection algorithm is.