The Transient Characteristics And Application For Lighting Surge Of EHV Transmission Line

Supported by Hebei Natural Science Foundation under grant No.E2005000561, the surge impedance of the different places of the towers and the lightning simulation model of the transmission line are mainly researched in this paper. The main contributions are as follows:The search methods of surge impedance are generalized, and some of them are analyzed simply. The surge impedance of the different places of the towers are computed by HIFREQ in CDEGS according electromagnetic field simulation.According the electric transmission line FDTD model, the different places voltage of the tower are computed, which provide the criterion for insulator flashover. Test is developed and the surge impedance of reality reduction models with ground mat are computed and analyzed.Combined with the electrical geometric model of transmission line, the computation method is modified, and flashover rates are computed in different conditions.