Extra high voltage transmission lines have such characteristics as high erection position

multiple erection circuits and long distance transmission

making them susceptible to lightning strikes during operation

thus posing a threat to the stability and reliability of power system. As for the accurate identification of lightning strike type

a kind of lightning strike type identification method of extra high voltage line is proposed. A 500 kV double circuit drum shaped tower is taken as an example

a simulation model considering multiple factors is set up in the ATP-EMTP platform to analyze the characteristics of lightning shielding and lightning back-striking under different fault conditions. A method based on improved Hilbert-Huang transform is proposed to study the fault transient signal passing through the tower after lightning strike. The criteria is constructed by the different distribution trend of intrinsic mode function (IMF) of the fault signal under variant contribution rate. It is found by verifying the stability of the distribution through different parameters that the distribution trend is basically not affected by the magnitude of lightning current and ground resistance

and has stable and clear boundaries

which can accurately identify the type of lightning fault. It is of great significance to promptly identify weak insulation point of line and develop more specific lightning protection measures.