Research on lighting fault identification technology of transmission lines based on non-contact sensing

Abstract

According to field operation records, lightning stroke accounts for 60% of transmission line failures. Therefore, it is of great significance to strengthen lightning protection of the power system. However, there are several lightning faults, and the corresponding protection methods differ. Consequently, identifying lightning stroke faults will be beneficial to take corresponding lightning protection measures. This paper investigates the mechanism of different lightning strike faults, and simulates them by a 110kV transmission line EMTP-ATP model. Analysis and simulation show that the direction of tower current represents lightning’s polarity; the insulator voltage’s direction differs when shielding failure or back striking occurs. If insulator flashovers, the voltage of the insulator drops down to zero, and as the transient process comes to an end, the voltage of the insulator on the nearby tower decreases to zero as well; after the occurrence of back striking flashover, the direction of insulator voltage on nearby tower alters. Based on those features, insulator voltage and tower current are introduced as a characteristic signal, and their direction and rms of them are formed as recognition parameters for lightning stroke identification. The EMTP-ATP simulations demonstrate that the proposed method is correct and effective, and the recognition rate of different lightning faults is 100% under the abovementioned method.