灵活接地系统的高阻接地保护研究  

Research on High Resistance Grounding Protection of Flexible Grounding System

作　　者：秦昌嵩 QIN Changsong(Nanjing Guodian Nanzi Grid Automation Co.,Ltd.,Nanjing 211153,China)

机构地区：[1]南京国电南自电网自动化有限公司,江苏南京211153

出　　处：《电工技术》2023年第6期127-129,133,共4页Electric Engineering

摘　　要：灵活接地系统的配电网正常运行时中性点不接地,当发生单相接地故障时中性点自动转为小电阻接地。当前灵活接地系统依靠零序过流保护切除故障,但仍存在高阻接地故障无法准确选线、灵敏度不足的问题,零序过流保护频繁在故障熄弧期间复归,导致故障切除时间长,引起接地变烧毁、110 kV主变跳闸等事故。研究了灵活接地系统的电压电流特性,提出了适用于配电网灵活接地系统方式下的单相接地故障快速处置方法,并基于此设计了一款线路保护测控装置,集成了稳态和暂态量的选线技术,能够精准识别、快速隔离故障,提高了接地故障保护可靠性和灵敏度。When the distribution network of the flexible grounding system is in normal operation,the neutral point is not grounded.When a single-phase grounding fault occurs,the neutral point is automatically converted to small resistance grounding.The current flexible grounding system relies on zero-sequence overcurrent protection to remove faults,but there are still problems such as inability to accurately select high-resistance grounding faults and insufficient sensitivity.Zero-sequence overcurrent protection frequently returns during the arc extinguishing period,resulting in long fault removal time,causing accidents such as ground change burnout and 110 kV main transformer tripping.The voltage and current characteristics of flexible grounding system are studied,and a rapid handling method for single-phase grounding fault suitable for flexible grounding system mode of distribution network is proposed.Based on this,a line protection measurement and control device is designed,which integrates the line selection technology of steady-state and transient quantity.The device can accurately identify and quickly isolate faults,improving the reliability and sensitivity of ground fault protection.

关 键 词：小电流 灵活接地系统 单相接地故障 间歇性故障 高阻接地 可靠性 

分 类 号：TM774[电气工程—电力系统及自动化]