Study of Lightning Overvoltages Protection of 400 kV Gas Insulated Substation
Overvoltages are unpredictable and extremely dangerous for the electric power system. The causes of overvoltages are different, but lightning is considered as one of the most serious causes of overvoltages. High voltage substations are one of the main parts of the power system whose faults caused by overvoltages can lead to outage of large part of power system. Therefore, overvoltage protection of a high voltage substation is very important. In order to protect the substation as much as possible from the effects of the overvoltages, it is necessary to implement elements that can help reduce these effects, for example surge arresters. This paper presents the effects of the use of surge arresters in high voltage, gas SF6 insulated substation, modeled in the EMTP-RV (Electromagnetic Transient Program-Restructured Version) software. An accurate representation of lightning surge incoming in the substation is very important because it strongly affects the design of overvoltage protection system. In this paper parameters of lightning strikes are determined using Sigma Slp software.