配电网小电阻接地缺陷性分析及动态电阻接地研究

Defect Analysis of Small Resistance Grounding and Dynamic Resistance Grounding in Distribution Network

配电网小电阻接地方式主要存在供电可靠性低、发生高阻接地故障时选线失灵的问题。本研究将建立小电阻接地模型进行理论分析,并针对目前小电阻接地系统所出现的缺陷,提出一种经动态电阻接地方式。该方式根据三相电压、中性点电压以及各馈线零序电流之间的关系将不同单相接地故障进行分类处理。特别是在解决高阻故障时,通过动态电阻接地方式增加各馈线零序电流进解决小电阻存在的高阻选线缺陷。为验证该接地方式的有效性,在漯河真型试验场进行了现场试验。试验表明动态电阻接地方式在保留小电阻接地方式优点的同时,有效的解决了小电阻接地方式供电可靠性低以及高阻选线失灵的问题。

The small resistance grounding method of the distribution network mainly has the problems of low power supply reliability and failure of line selection when a high-resistance ground fault occurs. The author will establish a small resistance grounding model for theoretical analysis. Aiming at the defects in the current small resistance grounding system, a dynamic resistance grounding method is proposed. This method classifies different single-phase grounding faults according to the relationship between the three-phase voltage, the neutral point voltage, and the zero-sequence current of each feeder;especially when solving high-resistance faults, the zero sequence current of each feeder is increased by dynamic resistance grounding to solve the defect of high resistance line selection with small resistance. In order to verify the effectiveness of this grounding method, field tests were carried out at the Luohe true-type test site. The test shows that the dynamic resistance grounding method can effectively solve the problems of low power supply reliability and failure of high resistance line selection while retaining the advantages of the small resistance grounding method.