新型机电混合断路器及其电流转移过程分析

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

为降低传统机械式断路器动作过程产生的触头烧蚀、暂态恢复电压与介质恢复过程的竞争、关合涌流等暂态过程的影响,该文提出一种用于配电系统的新型机电混合断路器拓扑结构:双断口真空灭弧室负责通载额定电流,动作时电流转移到与其并联的背靠背大功率整流二极管,由二极管完成开关的零区过程。该拓扑结构可以消除上述合分操作可能产生的暂态过程,且能保持机电开关各自的优势。首先分析新型机电混合断路器的动作过程和原理并进行仿真;然后搭建实验样机,进行机电部分的电流转移特性实验。仿真及实验的结果表明:电流转移的时间受二极管的特性参数影响,存在饱和效应;在本实验条件下的转移电流峰值达到二极管额定电流3倍时电流转移率开始减小,达到5倍时电流转移趋向于饱和;该文给出的拓扑结构在典型参数下能够实现10kA短路电流的微弧甚至无弧分断,断路器的机电混合模式对电力开关的发展具有重要意义。

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.