Lightning study of windfarm collector system

This paper presents a numerical modeling and simulation of a lightning study of 115kV and 34.5kV overhead line (OH) connected to windfarm collector system. The electromagnetic transient program PSCAD/EMTDC is used to model and simulate the OH line and other substation equipment. Shielding failure and back flashover studies are performed to characterize the magnitude of the lightning overvoltages. The effect of variation in tower grounding resistance on lightning overvoltages is also analysed. Insulation requirements and protective ratios of main transformers, wind turbine generator (WTG) transformer and circuit breakers are verified with respect to voltage developed during lightning. The protective ratios are compared as per IEEE std C62.22-1997.