提高10kV配电网零序电流保护正确动作率方法  

Measures to Improve Correct Operation Rate of Zero Sequence Current Protection in 10kV Distribution Network

作　　者：蔡燕春 张少凡 秦绮蒨 CAI Yanchun;ZHANG Shaofan;QIN Qiqian(Guangzhou Power Supply Bureau, Guangzhou 510620)

机构地区：[1]广州供电局电力调度控制中心,广州510620

出　　处：《云南电力技术》2017年第6期32-36,共5页Yunnan Electric Power

基　　金：广州供电局有限公司科技项目(GZHKJ00000020)

摘　　要：广州供电局是国内最早在10 k V系统采用小电阻接地方式的单位,至今已积累了近30年的运行经验。中性点经小电阻接地的配电网采用零序电流保护切除接地故障,若零序电流保护正确动作率低,则会扩大事故范围,降低供电可靠性。本文从零序CT、二次回路接线、保护定值等方面分析零序电流保护不正确动作的原因,提出采用闭环式的专用零序CT、明确零序CT电流外皮地线的安装要求、采用一次加电流方法进行CT变比实测、规范二次回路接线等具体措施,以提高10 k V配电网零序保护正确动作率,供在10 k V配电网中逐步推广中性点经小电阻接地方式的单位参考。The small resistance grounding mode was earliest used in Guangzhou Power Supply Bureau＇ s 10kV distribution network, which has accumulated nearly 30 years of operating experience. The zero-sequence current protection is used to cut off ground fault. If the correct action rate of the zero-sequence current protection is low, the fault-influenced scope will be enlarged and the reliability of the power supply will be reduced. This paper analyzes the causes of incorrect action of zero sequence current protection from the aspects of zero-sequence CT, secondary circuit wiring, protection setting values and so on. A series of measures have been proposed, such as closed-loop special zero-sequence CT, definition of the installation requirement of zero-sequence CT, measuring the CT ratio by means of adding current, standardizing the secondary circuit wiring and so on. All these specific measures to improve the correct rate of zero-sequence protection in 10kV distribution network, can be referenced by all units which adopts the neutral grounding with small resistance.

关 键 词：配电网 小电阻接地 零序电流保护 正确动作率 

分 类 号：TM773[电气工程—电力系统及自动化] TM862