混合型直流熔断器用灭弧熔断器单元低过载电流开断特性优化设计研究

Analysis and Optimum Design on Low Overcurrent Interruption Characteristics of Fuse Element Used in Hybrid DC Fuse

灭弧熔断器单元是混合型直流熔断器的重要组成部分,其承担着为高速开断器提供介质恢复时间及直流灭弧开断功能,由于直流灭弧熔断器开断低过载电流能力较弱,易出现过热、喷弧等故障导致开断失败。该文针对这一问题,结合仿真与试验分析直流灭弧熔断器低过载电流开断困难机理,并在此基础上提出设置熔体薄弱狭颈的解决方案,改进设计了额定2000V/1600A混合型直流熔断器用灭弧熔断器单元,进行故障电流开断试验,试品成功开断了2k A低过载电流及7k A短路电流,验证了改进方案的正确性,相关结论可应用于混合型直流熔断器灭弧熔断器单元的设计,能有效提升混合型直流熔断器的保护能力。

As an important component of hybrid DC fuse, the fuse element plays the role of providing dielectric recovery time and DC current interruption. However, the ability of low overcurrent interruption of DC fuse is so weak that it often results in overheating or arc spray which leads to interruption failure. In this paper, a novel structure of fuse element with weak narrow neck was proposed on the basis of analyzing the mechanism of the weak interruption ability of DC fuse. Besides, an optimized DC fuse element for 2000 V/1600 A hybrid DC fuse was designed and a fault current breaking test was carried out as well. The results show that the 7 k A short current and 2 k A overcurrent are interrupted respectively, which verifies the correctness of the novel structure. These conclusions can be applied in the design of hybrid DC fuse to improve its protection ability.