Modeling of Lightning Shielding Failure in UHV Transmission Line Based on Randomness Theory

The operation data obtained abroad indicates that shielding failure in AC UHV transmission system mostly accounts for the tripping-out accidents introduced by lightning striking the transmission line. Based on the discharge theories of long air gap and randomness theory, a leader progression model of lightning shielding failure is presented in this paper. The simulation results shows the good agreement between this model and the field data.