Research on the Lightning-Struck Tower Localization and Fault Identification Based on Residual Magnetism Detection

At present, the precise location of fault tower struck by lightning still relies on manual line inspection, the search process is time-consuming and laborious. This paper proposes a lightning-strike fault tower localization criterion based on detection of residual magnetism on the tower. This paper firstly calculates the tower shunt coefficient of lightning current under different lightning striking faults. After a transmission tower is struck by lightning, residual magnetism is generated in the tower. An experiment platform is designed to study the residual magnetism characteristics of the fault and adjacent towers in the cases of both back flashover and shielding failure flashover at 110 kV, 220 kV and 500 kV voltage level. The specific values of residual magnetism under different conditions are obtained, and it is found that the residual magnetism of the fault tower is far larger than that of the adjacent towers. Besides, the effect of power frequency follow current during the flashover is also taken into account. Based on the experimental results, the residual magnetism law is summarized, and the criterion of lightning-struck tower localization and fault identification based on residual magnetism detection is proposed. Finally a field test was conducted which verified the validity of the method proposed.