Aiming at a series of power network accidents caused by relay protection fault in Intelligent substation

this paper studies the fault diagnosis method of relay protection key link in prefabricated cabin intelligent substation.Firstly

the data needed for fault diagnosis of relay protection are pre-processed

and a fault diagnosis method for current measurement loop based on the identification of generalized transformer ratio is proposed. At the same time

the abrupt fault of electronic transformer is studied. Based on distinguishing the fault mode of electronic transformer and recognizing the characteristics of primary system

the method of diagnosing abrupt fault of electronic transformer is put forward. Through the Matlab simulation of a 220 kV prefabricated cabin intelligent substation in Changsha

the validity of the method is verified

and a simple and efficient on-line diagnosis method for relay protection fault of substation is provided.