Discussion on design standard of low-voltage IT grounding system in underground mine
-
摘要: 介绍了矿山井下低压IT接地系统第一次接地故障的原理，指出GB 50070—2009《矿山电力设计规范》要求“配电系统相导体和外露可导电部分之间第一次出现阻抗可忽略的故障时，故障电流不应大于5 A”的规定是没有实际意义的；通过计算比较IT系统和TN系统单相接地故障时的触电电压和电流，可知在采用IT系统时直接触电的人身触电电流与采用TN系统时基本相同，而在间接触电的情况下IT系统优于TN系统。Abstract: The paper introduced principle of grounding fault of low-voltage IT grounding system in underground mine for the first time, and pointed out it is meaningless of a requirement in GB 50070-2009 Design Code for Electric Power in Mine that fault current should not be greater than 5 A when fault with negligible impendance occurred between phase conductor and exposed conductive part of power distribution system for the first time. It also calculated electric shock voltage and current when single-phase grounding fault occurred in IT system and TN system respectively, and got conclusion that the current of direct electric shock in IT system is the same as the one in TN system, and IT system is better than TN system under condition of indirect electric shock.
-
Keywords:
- IT grounding system /
- grounding fault /
- fault current /
- touch voltage
-
计量
- 文章访问数: 58
- HTML全文浏览量: 6
- PDF下载量: 10
下载:
