Analysis on Novel Electro-Mechanical Hybrid Circuit Breaker and Its Current Commutation Process

In order to reduce the influence of transient process caused by the action process of the traditional mechanical circuit breaker, such as contact ablation, the competition between transient recovery voltage (TRV) and dielectric recovery (DR) process, and closing inrush current, this paper proposes a new type of electro-mechanical hybrid circuit breaker (EM-HCB) topology for the distribution system. In the topology, the double-break interrupters were responsible for carrying the rated current. During the action process, the current was commutated to the back-to-back high-power rectifier diodes in parallel, and the diodes completed the current zero-crossing process of the circuit breaker. This topology can eliminate the transient process that may be generated by the above closing and opening operations and maintain the advantages of mechanical and electrical switches. Firstly, the theoretical model and simulation of this topology were carried out to describe the action process of the novel EM-HCB. Then the experimental prototype was built to carry out current commutation characteristic experiments of the electro-mechanical part. The simulation and experimental results show that the time of the current commutation is affected by the characteristic parameters of the diode, and there is a saturation effect of the current commutation rate. When the peak value of the commutation current reaches three times the rated current of the diode, the current commutation rate begins to decrease. When it reaches five times, the current commutation tends to be saturated. The proposed topology can realize micro arc or non-arc breaking of 10kA short-circuit current under typical parameters. The electro-mechanical hybrid mode of the circuit breaker is of great significance to developing power switches. © 2022 Chinese Machine Press. All rights reserved.