变电站电源系统接地极阻值商榷.pdf

建続也乞”
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2ロ1ら年第3期」 LECTRICITY
变电站电源系统接地极阻值商榷
刘屏周(中国航空規划设计研究总院有限公司,北京市100120)
Discussion on Grounding Electrode Resistance of Power
Supply System in Transformer Substation
LIU Pingzhou (China Aviation Planning and Design Institute(Group)Co., Ltd, Beijing 100120, China)
Abstract: This article only involves substations值或接触电压允许值。低压系统发生接地故障,保护
the users of which adopt high- voltage measurement电器应自动切断电源。我国设计规范中给出变电站接
and self- management. Power frequency overvoltage in地极阻值要求,而在EC标准未见具体要求值。阐述
low-voltage systems or conduction breakdown voltage高压中性点有效接地系统或非有效接地系统,与低压
Ised by grounding faull voltage in high
TV系统或TT系统不同组合,确定变电站接地极阻
system should not exceed over- -voltage limit or值的基本原则,以更好理解EC标准未笼统提出接地
permissible contact voltage value in low- voltage system.极值要求的原因
Protection apparatus should be able to shut off power
关键词:功能接地;保护接地;接地极阻値;エ
automatically when grounding fault in low-voltage过电压:接触电压限值;电去防护;有效接地系
system occurs. Substation
grounding
统;非有效接地系统
resistance is required in national design specification
中侶分类号:TU89
文献识码
but the specific value cannot be seen in EC
doi:10.3969/j.is.1003-8493.2016.03.003
standard. Accordingly, this article states the different
combinations between high-voltage neutral point
effective grounding system or non-effective gr
1概述
system and low-voltage TN system or TT systern, to
determine the basic principle of substation grounding
电气装置接地涉及:①功能接地,多为供电系统
electrode resistance for better understanding why(如发电机组、电力变压器等)中性点的接地;2电气
grounding electrode resistance is not indistinctly装置外露可导电部分接地,起保护作用,故称为保护
required in IEC standard
接地。电气装置功能接地与保护接地示意如图1所示。
Key words: functional grounding; protective
TN系统接地兼具保护接地和功能接地两种目的
grounding; grounding electrode resistance; power TT系统接地分別承担保护接地和功能接地的作用。对
frequency overvoltage; contact voltage limit; protection于以保护为目的的接地,始终应予以优先考虑
against electric shock; effective grounding system
高压系统中性点对地可分为:中性点有效接地和
ton-effeetive grounding system
中性点非有效接地。中性点有效接地包括中性点直接
接地、经低电阻接地;中性点非有效接地包括中性点
摘要:本文仅涉及用户为高压计量、自行管理不接地、诸振(经消弧线)接地、高电阻接地等
的变电站,高压系统接地故障电压引起低压系统工频
高压系统中性点有效接地/中性点非有效接地与
过电压或传导故障电压,不应超过低压系统过电压限低压TN系统/T系统的不同组合,对变电站接地极
作者信息
刘屏周,男,中国航空规划设计研究总院有限公司,研究员。
35No.3