Aiming at the high safety risk of secondary equipment maintenance and fault isolation in intelligent substation, based on the analysis of secondary system fault state in intelligent substation, this paper proposes a fault diagnosis method of relay protection measuring circuit for secondary equipment in intelligent substation.Based on the measurement of transformer impedance, the fault diagnosis model is established by using the generalized transformation ratio, and the polarity fault is analyzed.The correctness and validity of the method are verified by simulation. The results show that the method can evaluate the fault condition of current and voltage measurement loop very well.This study provides a reference for the development of intelligent substation equipment fault diagnosis in China.
