Synchronous Control of Module Series Connection Interruption in 110 kV DC Vacuum Circuit Breaker

Synchronous control of circuit breaker with multi-breaks in series is one of the key technologies in direct current (DC) interruption field. In this study, a 110 kV DC vacuum circuit breaker with double modules and four breaks is taken as the research background. By the design of double-break high voltage DC (HVDC) breaking module, the time dispersion of opening and closing action of each series break is analyzed. The synchronization requirements of the whole circuit breaker and the synchronization parameters between multiple modules and multiple breaks are proposed, and the allowable range of DC breaking synchronization error is given. The intelligent algorithm is used to dynamically compensate the synchronous error between the breaks, and the optical fiber signal connection is used between modules to avoid electromagnetic interference. In order to verify the effectiveness of the synchronous control system, the synchronous error in opening operation of a vacuum circuit breaker with three breaks is tested. The test and analysis results show that the synchronous error range of 60 kV module with double break and 110 kV prototype with double modules can meet the requirements of mechanical parameters of HVDC circuit breaker. Finally, the concept of module redundancy is proposed, and the reliability index of rated demand of module numbers N+1 module redundancy design is proposed, which provides technical support for the application of vacuum circuit breaker in higher voltage level system. © 2020, High Voltage Engineering Editorial Department of CEPRI. All right reserved.