Influence of Modeling Methods on the Calculated Lightning Surge Overvoltages at a UHVDC Converter Station Due to Backflashover

The insulation coordination of the converter station is very important for the security and economy of the UHVDC power transmission system, and lightning surge overvoltages at the converter station should be calculated accurately. This paper mainly analyzes the influence of modeling methods on the lightning surge overvoltages caused by the backflashover of the incoming dc transmission lines by using the PSCAD program, such as the selection of lightning stroke current waveform, tower model, flashover criterion of the insulator, and so on. The simulation results show that modeling methods have a great influence on the backflashover lightning withstand level of the incoming dc transmission lines, but their influences on the lightning surge overvoltages of the equipment in the converter station are not so obvious.