基于DTU与FPI的小电流接地故障定位及信息建模

Small-current grounding fault line location and information modeling based on the interaction between DTU and FPI

为解决配电网小电流接地故障的选线及定位问题,文中对EMD算法的自适应滤波性质进行了分析,针对小电流接地故障电流经EMD分解出的IMF在不同故障角下展现的不同特征,在低频量较大时采用IMF低频层故障点突变方向,与较小时采用电容暂态能量大小作为判据进行故障选线,在此之上,基于DTU与FPI之间的相互配合对各相邻FPI进行波形对比最终得出故障位置,并遵循IEC 61850规约拓展了故障选线定位功能相关逻辑节点,为解决主站对DTU,FPI功能实现监控提供了参考。基于MATLAB/Simulink的配网小电流接地故障仿真验证了该选线定位方法的有效性。

In order to solve the small current fault line selection and location problems in distribution network system, the adaptive filtering property for EMD is formulated firstly. In view of the different characteristics showed by the IMF obtained by EMD under different fault angles, the direction of fault mutation in low frequency and the capacitance transient energy is chosen as fault line selection criteria when the low-frequency components occupy different proportions. The fault location can be finally determined based on the interaction between DTU and FPI with the adjacent FPI waveform comparison. Moreover, the logic nodes, which regard to fault line selection and location, are expand according to IEC 61850, which also provides reference to the way of realizing the function and monitoring of DTU or FPI. The effectiveness of the proposed fault line selection and location methods are verified by the simulation results of the small current grounding fault in distribution network built in MATLAB/Simulink.