铁路小电流接地系统火灾安全隐患分析

Analysis of Fire Safety Hazard of Railway Small Current Grounding System

随着城市的发展,城市配电网中10V高压总电缆里程增加,电缆容性电流也随之增大,导致总容性电流大于10A,故而须重新核算容性电流并改变其系统方式。这样会造成系统产生的故障电流,从100伏特秒增加到2 000~3 000伏特秒,即暂态过电压。过电压经过接地系统极易击穿电缆及设备绝缘层,造成火灾隐患。本文主要介绍了小电流接地系统常见的接地方式、接地故障产生的原理和引发火灾的原理,为排查接地故障火灾隐患提供一定的参考,对铁路供电可靠性有重要意义。

With the development of the city, the total mileage of 10 V high-voltage cables in the urban distribution network increases, and the cable capacitive current also increases, leading to the total capacitive current greater than 10 A, so it is necessary to re calculate the capacitive current and change its system mode. This will cause the fault current generated by the system to increase from 100 volt seconds to 2000~3000 volt seconds, that is, transient over-voltage. Overvoltage through the grounding system is very easy to break down the cable and equipment insulation layer, causing fire hazards. This paper mainly introduces the common grounding modes of small current grounding system, the principle of ground fault generation and the principle of fire, which provides a reference for troubleshooting the hidden danger of ground fault fire, and is of great significance to the reliability of railway power supply.