This paper discusses the application of surge arresters for MV RC snubber systems used for the protection of shunt reactors and circuit breakers against high-frequency overvoltages caused by the current chopping and re-ignition phenomena that can occur during shunt reactor de-energizations. RC snubbers are the most common surge suppression solution to minimise the probability of reignition, mitigate high-frequency oscillations, and dampen the peak value of TRV and shunt reactor terminal voltage. RC snubbers are equipped with surge arresters to complete the protection. Two surge arrester types, which are Gapped and Non-gapped MOVs, are investigated in this paper. The power system was modelled using PSCAD/EMTDC software. Considering with/without RC snubbers, comparisons between two surge arrester types are carried out in terms of the overvoltages. It also presents the energy requirement level of the surge arresters. The simulation results show that Gapped surge arrester overvoltage protection performance is superior to the Non-gapped equivalent arresters.
Optimizing Application of MV Surge Arresters in Resistor-Capacitor (RC) Snubbers
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