Development of HVDC Circuit Breaker and its Interrupting Test

The authors have developed a DC circuit breaker (DCCB) which interrupts a DC current by injecting a high-frequency reverse current from a commutating capacitor to be superposed to DC current and forcibly creating a current zero point. A breaking part consists of a vacuum interrupters or a SF6 gas, interrupters of the most advanced design connected in series or in combination to attain a high interrupting capabilities. The commutating current is introduced into the interrupter through a pulse transformer so that DCCB can be conveniently used in the system. A 25OkV-3500A DCCB system with these features was designed, manufactured and tested with successful results.