煤矿井下低压电网电流故障保护系统的研究

本文描述煤矿中下低压电网中电流故障保护系统的工作原理。分析对称短路相敏保护特性曲线的确定方法，设计负序电流滤波器，建立过负荷保护的数学模型，讨论了影响保护动作可靠性的各种因素。介绍以单片机为中央控制单元所构成电流故障保护系统的硬件结构和软件框图，中前对保护系统作了测试试验，动作指标符合设计要求。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。

STUDY ON THE CURRENT FAULT PROTECTIVE SYSTEM IN UNDERGROUND LV CABLE NETWORKS

This paper narrates the fundamental principle of overcurrent protective system in underground LV cable networks. Much attention is paid to the analysis of the method how to define the characteristic curves of phase sensitive symmetrical short circuit protection,the design of negative sequence current filter,the definition of the mathematical model of overload 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 has been tested before applied to underground LV distribution networks,The results obtained are conformity with the design specification.The field experience shows that the protective system is good a practice in stability and reliability, and will be of great applied value in mining industry.