Research on Lightning Overvoltage and Its Suppression Method of High Coupling Current Limiting Reactor Used to 500kV Transmission Lines

The fault current limiter (FCL) based on high coupling split reactor is a new technology to realize current suppression and current interruption in recent years. This paper introduces the new FCL developed by China Southern Power Grid Corporation for interrupting short-circuit current over 90kA in 500kV power grids. In this paper, the lightning over-voltage and insulation coordination of the installed FCL in a 500kV transmission system is studied, along with which, the over-voltages of other main apparatus, such as transformers, bushings and CVTs in power station, are simulated and checked. In the calculation, different current limiter operation status, including normal mode and current limiting mode, different lightning modes of shielding and counterattack are considered. The influence of different shunt capacitors connected with the current limiter units on the lightning overvoltage is also studied and discussed. According to the calculation, the over-voltage level of the FCL is obtained and used to guide its lightning insulation coordination design.