Identification Method of Back Flash Overvoltage and Shielding Failure of Transmission Lines Considering the Effect of Impulse Corona

According to operational experience,the direct lightning strike is the main factor leading to tripping of transmission lines.The rapid intelligent identification of the back flash overvoltage and the shielding failure is of great importance to the evaluation of lightning withstand level as well as discovery of the vulnerable point for the lightning protection.Consequently,based on ATP-EMTP,a lightning overvoltage simulation model containing the influence of the impulse corona was established,and the impact of impulse corona on the propagation process of overvoltage was researched.Based on the origin mechanism of overvoltage generation,the morphological pattern spectra were applied to analyze the waveform characters of back flash overvoltage and shielding failure from the geometric configuration aspect.Moreover,compared with wavelet on frequency domain characteristics calculation,the accuracy and speed of morphology was verified.The characteristic geometric quantity of morphological pattern spectra was generated and input into the SVM to construct the intelligent classification machine.The identification accuracy was verified by 48 different overvoltages.It is verified that this method is effective in the identification of back flash overvoltage and shielding failure,and provides valuable data reference for the lightning protection of the transmission lines.