Application Solution of Limiting Lightning Overvoltage by HVLPF

Lightning overvoltage is one of the main reasons for threatening the safe operation of a transformer substation, and the main protection scheme is currently to reasonably configure the number of lightning arrester and the location of the arrangement. However, the installa-tion of the number of lightning arrester will increase the cost of the substation. The frequency range of lightning over voltage is generally 20 kHz to 1 MHz, which is far more than the 50 Hz of the power frequency voltage. According to this characteristic, we pro-posed an alternative measure of the HV L-C filter which is composed of the inductance coil and the coupling capacitor. Taking a 500 kV gas insulated substation(GIS)as the research object, we designed an HV L-C filter of which the inductance value is 314 μH, the capacitance value is 12.1 nF, the creepage distance is 23 816 mm, and the dry arc distance is 6 m, and verified the excellent overvoltage limiting performance based on EMTP-ATP simulation. Moreover, we put forward a lightning protection scheme of air insulated substation(AIS)surge arrester and high voltage L-C filter. The simulation and comparison results reveal that the AIS lightning arrester combined with a high voltage L-C filter is more effective and economical in limiting lightning overvoltage. It is proved that the HV L-C filter can replace GIS surge arrester to more effectively complete lightning protection for GIS substation. © 2019, High Voltage Engineering Editorial Department of CEPRI. All right reserved.