Wind power integration on power system influences the measured impedance as well as operation characteristics of distance protection. The impacts has particularity for wind farm connecting to the grid with T-type. The distance protection measure impedance formula is deduced for wind farm connected to dual power system with T-type. The impacts of fault location, operation mode of wind farm and transition resistance on measured impedance are studied, and the influence of these factors on the distance protection and next distance protection are discussed. Taking a wind farm connected to the grid with T-type in Xinjiang as an example, the simulation model is established, the correctness of theoretical analysis are verified by simulation. The study provides a theoretical basis for relay setting and configuration, and has theoretical significance and practical value.