Without RC filter during switching
For reactive power compensation, and mainly for voltage regulation purposes, shunt reactors are used at different voltage levels in the electric utility. During the turn-off action of the breaker or contactor of a shunt reactor, huge over-voltages are created due to the sudden interrupt of an inductive current. In order to prevent any harm to system equipment, voltage clampers, so called RC snubber filters, consisting of resistive and capacitive elements, are used in parallel with shunt reactors. They clamp the voltage overshoot due to the current interruption and damp out the oscillations safely.