中压配电网变电站内电缆接地故障区段定位研究

Research on the Location of Cable Ground Fault Section in MediumVoltage Distribution Network Substation

目前针对线路本体单相接地故障的故障定位技术已经成熟,但关于开关柜内电缆头的故障定位技术研究甚少。针对开关柜内电缆头发生单相接地故障时,接地选线装置无法识别、定位的问题,建立了开关柜内电缆头故障模型,利用三相CT的合成零序电流信号与零序CT的零序电流信号,通过变分模态分解法(VMD)分解后,计算灰色关联度,对两信号进行相似性分析。以此提出了基于三相CT和零序CT测量信息的开关柜内电缆头精确故障定位技术,并通过ATP仿真软件验证了所提故障定位技术的正确性与可行性。

At present,the fault location technology for single-phase grounding fault of cable line has matured,but there is little research on cable head fault location technology.Aiming at the problem that the fault location device can not identify and locate when a single-phase grounding fault occurs in the cable head,a cable head fault model is established.Using the synthetic zero-sequence current signal of three-phase CT and the zero-sequence current signal of zero-sequence CT,the gray correlation degree is calculated by variational mode decomposition(VMD),and the similarity analysis of the two signals is analyzed.Therefore,a precise fault location technology for cable heads in switchgear based on three-phase CT and zero-sequence CT measurement information is proposed.The correctness and feasibility of the proposed fault location technology are verified by ATP simulation software.