含DG的小电流接地系统单相接地故障定位  

Single phase-to-earth fault location of small current grounding system with distributed generation

作　　者：钱虹[1] 黄正润[2] 阮大兵[1] 

机构地区：[1]上海电力学院自动化工程学院,上海200090 [2]福建省电力有限公司检修分公司,福建福州350001

出　　处：《电机与控制学报》2014年第8期17-23,共7页Electric Machines and Control

基　　金：国家高技术研究发展计划(863计划)(2011AA05A106)

摘　　要：对比分析含分布式电源(DG)与不含DG的小电流接地系统在发生单相接地故障时暂态零序电流的特点,得出DG的加入不影响各线路的暂态零序电流分布。因暂态零序电流中存在多个频率分量,虽然对于某一频率而言,故障线路与健全线路电流相位(方向)相反,但多个频率的叠加会使得这样的方向性变得模糊。采用小波变换的Mallat算法对各线路的暂态零序电流进行分解和重构,从而获得低频逼近部分aN和高频细节部分dN。据此,提出选线判据:对于含DG的小电流接地系统,在暂态零序电流的初始阶段,故障线路暂态零序电流的细节分量幅值是所有健全线路的幅值之和,相位与健全线路相反。最后,建立仿真模型,对含DG的中性点经消弧线圈接地系统和中性点不接地系统进行了仿真实验,实验结果证明该方法故障判别准确,选线灵敏度高,实用性强。Characteristics of transient zero sequence current was analyzed when small current grounding system occur one-phase ground fault.Transient zero sequence current contains multiple frequency component.Although the crrrent phase of fault line is opposite to perfect line for a specific frequency,the superposition of many frequency makes such a opposition blurred.Transient zero sequence current of each line was decomposed and reconstructed by Mallat algorithm of wavelet transform,and low-frequency approximation part and high-frequency section were got.A fault line selection criterion was proposed：in the initial stage,the amplitude of detail component of the fault line‘ s transient zero sequence current equals the sum of all pefect lines,and the phase is opposite to the perfect line.Finally,the simulation model was established.The simulation experiments are made for neutral grounding through arc-suppression coil system and neutral ungrounding system.The experimental results show that the method is accurate,sensitive and practical for fault line judgment.

关 键 词：分布式电源 小电流接地系统 故障选线 小波变换 细节分量 

分 类 号：TM755[电气工程—电力系统及自动化]