Rastall, Tim
Biography
Mr. Rastall received his M.Eng. in Electrical Engineering from The University of Sheffield. He specializes in Grid Code compliance solutions for large-scale industry and renewables and has extensive direct experience in modelling and application of surge arrestors for protection of MV/HV capacitor banks as well as harmonic filters.
If distributed generation sites require reactive power and voltage stability, shunt reactors are a cost effective solution. However, their switching can introduce voltage disturbances at the connection point due to high magnitude inrush currents. Improvements such as controlled switching technologies have allowed for inrush currents during energization to be minimized and have increased viability of shunt reactors. This presentation discusses application of surge arresters for MV RC snubber systems used to protect 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-energization. Two surge arrester types – gapped and non-gapped MOVs – are investigated.