Identification of induced lightning and direct striking based on wavelet transform

Based on the different discharge processes of lightning striking, lightning overvoltage can be divided into two types: induced lightning overvoltage and direct lightning striking overvoltage (including back-flash and shielding failure). The characteristics of these overvoltages are investigated in this paper and it is concluded that induced lightning overvoltage exists simultaneously in three phases of the transmission line and similarity of its inter-phase is more significant than that of direct striking lightning overvoltage. Therefore the energy matrix similarity dependent method with the implement of wavelet transform can be applied to identify them. Mass simulation with consideration for many different fault conditions has been computed to prove its effectiveness based on ATP.