Identification of direct lightning strike faults based on mahalanobis distance and S-transform

Direct lightning strike is one major cause of transmission line outage. A study on identification of direct lightning strike faults is beneficial for efficient and relevant repair, which is meaningful to lightning protection. In this paper, the reason for focusing on the lightning current of phase wires at the observation points is briefly explained first. Second, the simulation model by Alternative Transients Program- Electromagnetic Transients Program software (ATP-EMTP software), including the corona model, is established and its validity is proved. Third, the characteristic quantities based on Mahalanobis distance and S-Transform are deduced and presented, respectively. The accuracy rate of this identification method using simulation data is then obtained. Finally, to test its effectiveness, the identification method is applied to identify three actual lightning current examples. And the results from this identification method are reasonable and verifiable by time-domain characteristics from literature and the data acquired by Lightning Location System. This identification method is built on the measurement of the lightning current monitoring system based on differential-integral loop. In addition, this method is applicable to the identification of lightning current on phase wires.