In order to solve the influence of the inverter control strategy on the fault characteristics of the distribution network with Inverter Interfaced Distributed Generator (IIDG),a new principle of pilot protection based on positive sequence component integrated impedance is proposed. The principle uses the ratio between the difference of two terminals positive sequence voltage phasor of the transmission line and the sum of the two terminals positive sequence currents phasor of the same transmission line to form a positive sequence component integrated impedance. When the faults occur in external or internal area, the amplitude of the positive sequence component integrated impedance varies obviously, so that the internal and external faults on the line can be distinguished. The new principle has obvious characteristics, such as easy tuning, free from the influence of distributed generation control strategy, and strong resistance to transition resistance. The validity of the principle is verified by PSCAD simulation. This work is supported by Key Research and Development Program of Sichuan Science and Technology Department (No. 2017GZ0385).