Abstract:

 In order to reduce the construction investment of large scale hydropower station, taking Gezhouba Dajiang hydropower station and Xiluodu Left Bank project as examples, this paper simulated and calculated the lightning invasion waves with using EMTP program. The calculation results show that the hydropower station which the connection between main transform and switch station uses overhead line can cancel the installation of arresters at busbar, but arresters should be installed at main transform; the hydropower station which the connection between main transform and switch station uses gas insulation line （GIL） can make busbar and main transform share a set of arresters. The large scale hydropower station always has lot of main transformers, and the arrester price of the gas insulated switchgear （GIS） in main transformer is expensive. So the optimization of GIS arrester in main transformer can bring great economic benefits. With the use of the optimized arrester arrangement scheme, the lightning protection reliability of 500 kV large scale hydropower station can be high enough.

Key words: 500 kV large scale hydropower station, arrester, overvoltage, main transformer