To get a fault identification method for overhead transmission lines and to provide a theoretical basis for development of corresponding fault identification systems

a simulation model of overhead transmission line is built.And the transient travelling wave currents due to lightning shielding failure

back strike and non-lightning strike are simulated by using the electromagnetic transient simulation software ATP-EMTP.By comparison of simulation results and theoretical analysis

identification criteria of the failures due to lightning strike

non-lightning strike

shielding failure and back strike are obtained for fault identification in terms of the differences in transient travelling wave current characters such as length of wave tail

with or without inverted pulse

etc.The proposed fault identification method can be taken as a theoretical foundation for intelligent diagnosis of transmission line tripping fault

on which monitoring terminal of intelligent diagnosis can be developed

and expert system of intelligent diagnosis for transmission line tripping fault can be further established.