APPLICATION OF CONTROLLED (POINT ON WAVE) SWITCHING FOR 400 kV SHUNT REACTOR

Transmission lines loaded below their surge impedance present a significant source of reactive power in network, that can lead to local voltage increase. Transmission system operators around the world turn to shunt reactors in combination with a conventional high voltage circuit breakers to cope with voltage issues. Implementation of such solution introduces a significant increase in the number of switching transients. Using controlled switching technology (Point on Wave), through individual switching of each breaker pole at optimal time, it is possible to limit reactor inrush current when shunt reactor is energized and the recovery voltage when it is deenergized. The paper presents the negative effects of uncontrolled switching of shunt reactor on transmission system. The technique of controlling the timing of circuit breaker switching is presented as a tool to mitigate the negative effects of switching transients. Algorithm for controlled switching of the circuit breaker has been tested in laboratory. Test setup is made of Point on Wave Intelligent Electronic Device (IED) and HIL device used to simulate 400 kV shunt reactor and circuit breaker. The devices exchange information using IEC 61850 Sampled Values and GOOSE protocol. Experimental results confirm limitation of inrush current magnitude when shunt reactor is energized by controlled switching device.