Shunji Tokuyama

Development and Interrupting Tests on 250KV 8KA HVDC Circuit Breaker

This paper describes the circuit and component selections, development and equivalent circuit test results on an HVDC circuit breaker for an HVDC transmission line. A puffer type SF6 gas interrupter for AC circuit breakers is utilized for interrupting DC current with injection of high-frequency inverse current from a commutating capacitor precharged to HVDC line voltage. Also, the effectiveness of application of the HVDC breaker to an HVDC system with two parallel transmission lines is demonstrated through the EMTP simulation.

Development and Field Application of Metallic Return Protecting Breaker for HVDC Transmission

This paper describes the system requirements, circuit and component selections, development and field tests on a metallic return protecting breaker for an HVDC transmission system. Self oscillation phenomenon, generated in the course of DC current interruption by an air blast circuit breaker, is utilized to force the current to zero. Also discussed is outlook for development of an HVDC main line circuit breaker.

Simulations on Interruption of Circuit Breaker in HVDC System with Two Parallel Transmission Lines

This paper describes the Erectro Magnetic Transients Program (EMTP) simulation results for a study on specifications and duty of an HVDC circuit breaker in an HVDC system. The HVDC breaker employs an inverse current injection method and a capacitor precharged from the line voltage. The HVDC system is mono-polar, but has two parallel transmission lines and is the simplest multi-terminal system. The simulations demonstrated that the HVDC breaker can interrupt successufully under various breaking conditions.