HYDC Vacuum Circuit Breakers

The effectiveness of the commutation principle, using vacuum interrupters as a means for interrupting high direct current at high voltage, has been demonstrated convincingly by a large number of tests. Currents in excess of 15 kA at 20 kV have been interrupted by a single device in an inductive circuit. Tests are reported in which higher current were cleared by paralleling interrupters. Interrupters have been tested in series, indicating that the principle can be extended to high voltages. A high speed mechanism is described which was designed specifically for circuit breakers of this type. The necessary technology for producing HVDC circuit breakers appears to be at hand.