Simulation of switching overvoltages in 400kV transmission system

The paper presents simulation results of switching overvoltages in slovak transmission system, which were realized in purpose of 400kV powerlines surge arresters electrical parameters verification. Into class of switching overvoltages falls that effects, which originate in sudden changes of system parameters, as e.g. planned or emergency switching of power lines, transformers and other components (generators, rotating machines) and also in ground faults and short circuits. Overvoltages in power network can cause devices faults, in which interruption of electricity supply and stability loss threat and safety of power system can arise. For overvoltage simulation detailed mathematical model of whole SR transmission system was created in ATP, which includes precise models of substations, transformers, towers, power lines, isolators and other devices.