矿用隔爆型真空馈电开关中的过电流保护

从煤矿井下低压电网中装设过电流保护的重要性入手，描述了矿用隔爆型真空馈电开关中过电流保护的工作原理。重点分析了对称短路相敏保护特性曲线的确定方法，讨论了影响保护动作可靠性的各种因素。介绍了以单片机为中央控制单元所构成过电流保护系统的硬件结构和软件框图，下井前对保护系统进行了测试试验，动作指标符合设计要求。经现场运行表明该保护系统性能稳定，动作可靠，具有重要的应用价值。

OVERCURRENT PROTECTION IN UNDERGROUND EXPLOSION_PROOF VACUUM FEEDER SWITCHGEAR

This paper is based on the importance of installing overcurrent protective system in underground LV cable distribution network, narrates the fundamental principle of overcurrent protection in underground explosion_proof vacuum switchgear. Much more attention is paid to the analysis of the method how to define the characteristic curves of phase_sensitive symmetrical short_circuit protection and the discussion of all factors to interfere with its action reliability. Besides, the hardware block diagram and software flowchart of the protective system controlled by single_chip microcomputer is also introduced in the paper. The protective system have been tested before applied in underground LV distribution networks, The results obtained are conformity with the design specification. The field experience show that the protective system is good practice in stability and reliability, and will be of great applied value in mining industry.