Identification method of lightning shielding failure and lightning back flashover of high-voltage transmission line

The invention aims at providing an identification method for accurately extracting characteristic quantity and system fault transient information from an unstable high-frequency oscillation signal. The method may accurately identify a lightning stroke way just by means of a lightning stroke overvoltage signal recorded in a transformer station wave-recording device. The method comprises: acquiring the lightning stroke overvoltage signal; analyzing the lightning stroke overvoltage signal on a power transmission line by means of empirical mode decomposition (EMD); performing Hilbert transformation on an intrinsic mode function (IMF) including most of high-frequency signals; and using the instantaneous amplitude of the transformed IMF as the characteristic quantity and computing the variance rate of contribution of the characteristic quantity so as to discriminate power transmission line lightning shielding failure and lightning back flashover. The method is not influenced by the ground resistance of the line and lightning current amplitude, overcomes a defect of large data acquisition workload and misjudgment in conventional lightning current parameter actual measurement technology, and provides a theoretical reference for lightning protection analysis of the power transmission line.