Modeling Lightning Performance of Transmission Systems Using PSCAD

Lightning flash is one of the natural causes of faults in overhead transmission lines. The critical stroke current which causes flashover is a basic parameter characterizing the lightning performance of transmission lines. In recent times, there has not been any mature experience to be referred to either in China or other foreign countries of the study on lightning withstand level of UHVDC transmission lines. Using power system computer-aided design/electro-magnetic transient in DC system (PSCAD/EMTDC), the models of lightning current generator, transmission lines, towers, insulator strings and other associated components have been established in this paper. Meanwhile, According to the criterion of insulation flashover generally adopted in engineering in China, the dependence of lightning withstand level of ±500 kV transmission lines on tower impulse footing resistance has been investigated under the influence of DC polar working voltage, when a negative descending lightning strikes to a tower top. The simulation results agree with the theoretical value in an acceptable way, substantiating that the simulation models are reasonable. The study of this paper would be referential for lightning protection evaluation of UHVDC transmission lines in China.