Application of controlled switching to 500 kV shunt reactor current interruption

Summary form only given. To suppress re-ignition overvoltages caused when a 500 kV shunt reactor current is interrupted by a 550 kV one-break circuit breaker, a study was carried out on controlled switching. Using a full-scale test circuit, reactor current interruption tests were carried out to obtain the relation between opening phase angle and the generation of re-ignition. The results showed that even with the dispersion of circuit breaker operations taken into account, there were contact separation points free from high re-ignition overvoltages. It was also proved that no voltage escalations were caused by re-ignition and high-frequency arc extinction, and that the overvoltages due to current chopping were at safe level in terms of equipment insulation.