Lightning-against Capability of Insulator at 500kV Power Substation

This paper presents the result of research on lightning-against capability of 500kV insulator as well as new suggestions for choosing basic insulation levels (BIL) of equipment in 500kV power substation. To obtain the result, the author has used EMTP-RV software to simulate, analyse lightning propagation to the power substation and lightning voltage influence at different positions in power substation in some dangerous cases by creating atmospheric over voltage wave forms.The author also calculates dangerous cases of lightning propagation into power substation by atmospheric over-voltage occurring at the end-tower of 500kV transmission line, connected with power substation. Based on this, lightning impulse at important positions has been evaluated and recommendations are given for choosing smaller BIL in comparison with traditional requirements still ensuring normal operating conditions