﻿ 基于电压偏置的配电网单相接地过电压保护研究

# 基于电压偏置的配电网单相接地过电压保护研究Research on Single-Phase Grounding Overvoltage Protection of Power Distribution Network Based on the Voltage Bias

Abstract: In view of the threat of arc-over voltage to power equipment insulation when the single phase grounding fault in the medium voltage distribution network of industrial and mining enterprises, an active pressure regulating arc suppression limiting voltage protection method using voltage bias theory is presented in this paper. And the traditional concept of ground compensation has been changed. Firstly, the mechanism of arc overvoltage in low current grounding system of me-dium voltage distribution network is analyzed, and the necessity of full current compensation is put forward. Secondly, the principle of active pressure regulating arc suppression and pressure limiting protection is introduced, and the feasibility of the method is analyzed. Finally, an active pressure-regulating arc-suppressing protection scheme is designed, and the correctness of the method is proved in theory.

1. 引言

2. 配电网单相接地过电压机理分析

2.1. 中性点不接地系统间歇性放电现象

Figure 1. Gap discharge principle

2.2. 弧光过电压的产生

Figure 2. The generation mechanism of arc light overvoltage

3. 有源调压型消弧限压保护原理

Figure 3. The principle diagram of active regulating arc suppression pressure limiting protection

4. 有源调压型消弧限压保护设计方案

(a) 设计方案一 (b) 设计方案二

Figure 4. Electrical design scheme

1) 利用可控硅的高速开关特性，根据控制器实时检测到的放电角度，瞬时投入运行，可快速消除各种高频放电现象(可控硅动作是微秒级，间歇放电现象是毫秒级)。克服了故障早期的间歇弧光过电压的产生；

2) 可以在全频谱范围控制故障点接地电流大小，减少故障电流对绝缘的进一步破坏作用，降低单相接地造成的跳闸率；

3) 最大程度地缩短单相接地燃弧时间，对煤矿、化工等易爆场所来讲，可降低瓦斯与粉尘爆炸的风险；

4) 可实现高度自动化，投入和退出无需人为干预，接地故障的排除也可以用传统的拉路方式；

5) 安装方式与自动跟踪消弧线圈一样，但无需专用基建设施，节省投资。

5. 结论

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[2] 李志东. 35 KV系统接地故障分析及对策[J]. 中国高新技术企业, 2012(27): 105-107.

[3] Chen, Z.R., Zhang, B. and Mei, N. (2009) Study on the Arc-Suppression Coil Based on Sectional TCR. 2009 IEEE 6th International Power Electronics and Motion Control Conference, 1, 46-52.

[4] 郭勇刚, 寇洪宇. 自动调谐消弧线圈在供电系统中的应用[J]. 电气时代, 2004(9): 92-99.

[5] 李润先. 谐振接地是我国中压配电网最理想的接地方式[J]. 高电压技术, 1994, 20(1): 40-44.

[6] Huang, W.Y., Kaczmarek, R. and Bastard, P. (2004) An Efficient Treatment of Transient Residual Currents in Distribution Networks Grounded with Petersen Coil. 8th IEE International Conference on Developments in Power System Protection, Amsterdam, 5-8 April 2004, Vol. 2, 685-688.

[7] 要换年, 曹梅月. 电力系统谐振接地[M]. 第二版. 北京: 中国电力出版社, 2009.

[8] 陆国庆, 姜新宇, 欧阳旭东, 等. 高短路阻抗变压器式自动快速消弧系统——配电网中性点新型接地方式的实现[J]. 电网技术, 2000, 24(7): 25-28.

[9] 张雪梅. 自动调谐动态补偿消弧系统的应用[J]. 华东电力, 2008, 36(12): 150-152.

[10] 何颋. 自动调谐消弧线圈投入引起谐振过电压的原因[J]. 高电压技术, 2007, 33(9): 216-217.

[11] 徐涛, 李嫒. 35k V电阻接地系统故障分析与保护措施[J]. 供用电, 2009, 26(1): 42-44.

[12] 曾荣华. 10 kV配网中性点接地方式改造探讨[J]. 高电压技术, 2005, 31(6): 89-90.

[13] 李景禄. 实用配电网技术[M]. 北京: 中国水利水电出版社, 2005.

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