A resonant hybrid DC circuit breaker for multi-terminal HVDC systems

Abstract

High-voltage direct current (DC) transmission systems and multi-terminal direct current transmission systems are attracting attention for expanding the grid to promote introduction of renewable energy. Fault clearing in DC systems is difficult because there is no zero point of current. Hybrid circuit breakers are suitable for fault clearing in DC systems. Conventional hybrid circuit breakers have a hard-switching path that damages the switch. Hard switching damages the device and produces emissions due to harmonic noise. A novel resonant hybrid DC circuit breaker is proposed in this paper. The proposed circuit breaker reduces the damage to the switching device using soft switching due to the current zero point. The proposed circuit breaker is compared with conventional hybrid circuit breakers using numerical simulations. Interruption times and switching types of circuit breakers were compared. The simulation results of the fault clearing characteristics of the proposed breakers show that the proposed breakers have sufficient performance and are capable of stable reconnections in multi-terminal direct current transmission systems.