A Novel Thyristor-Controlled Voltage-Source-Based Forced Resonant Mechanical DC Circuit Breaker

A dc circuit breaker (DCCB) is an important equipment to ensure the safety of dc transmission system. However, the high manufacturing cost of the existing DCCBs is a hindrance to the development of dc transmission. In this article, a novel low-cost thyristor-controlled voltage-source-based forced resonant mechanical circuit breaker (TFR-MCB) is proposed. By using the resonant circuit and the equivalent voltage source based on cheap thyristors and low-voltage withstand capacitors, a large number of zero-crossing points can be generated in the required time, making the proposed TFR-MCB have high reliability and fast switching performance. In order to increase the gain of current oscillation while avoiding reverse recovery failure of the thyristors, a staggered control strategy and a fast-recovery bypass circuit are proposed and applied to the TFR-MCB. After a detailed thyristor recovery time comparison experiment, a 10 kV/3 kA TFR-MCB prototype was developed and completed the breaking test, verifying the feasibility of the proposed method and topology.