小电流接地系统保护的研究与应用

Research and Application of Protection in Small Current Grounding Systems

小电流接地系统由于具有供电可靠的优势在我国3.3~66 kV系统中广泛使用。分析了中性点不接地系统发生单相接地故障的特征,并讨论了小电流接地系统3种接地方式的优缺点。针对小电流接地系统无法实现故障选线,存在安全隐患的情况,提出了加装小接地电流系统消弧、过压、感电保护装置的方案。本文充分论证了该方案的实用性和经济性,反复试验证实该装置故障选线准确,运行稳定,满足变电站无人值守的条件。

Small current grounding systems are applied widely in 3.3~66 kV power system for the advantage of reliable power supply.In the paper,the feature when the single-phase grounding fault happens is analyzed.The advantages and disadvantages of three types of ground mode are discussed.Schemes adding arc extinction,over-voltage and electrification protection are proposed for the safety potential caused by that the fault can＇t located in small current grounding systems.The Schemes are proved to be practical and economical efficiency.Repeated experiments show that the device can meet the requirements of the accurate faulty line selection,the operation stability and the unattended substation.