一种中压配电网单相故障定位新方法

A new method of single-phase fault location in medium voltage distribution network

为解决中压配电网单相故障定位困难问题,以中压放射状配电网为研究对象,提出一种单相故障定位新方法。首先,分析了单相故障情形下故障相电流中高频暂态分量呈现出的一般性分布特点,找出该分量在故障场景下的主要流通路径。其次,借助小波变换定义并提取各馈线首端测量相电流的暂态有效能量,并设计了基于有效能量循迹法的单相接地故障定位判据。最后,以PSCAD/EMTDC为仿真平台进行仿真。结果表明,该方法能较好地识别不同中性点接地方式、过渡电阻及故障初相角条件下的单相故障,且在配电网参数不均匀、高阻接地、采样电流混有A/D噪声及考虑TA量测误差等现场恶劣工况下具有较强的识别能力,为中压配电网单相故障定位的工程应用提供了理论指导。

In order to solve the problem of single-phase fault location in medium voltage distribution network,a new method of single-phase fault location is proposed by taking medium voltage radial distribution network as the research object. Firstly,the general distribution characteristics displayed by high frequency transient component are analyzed in the fault phase current under the condition of single phase fault and the main flow path of the component in the fault scene is found out. Secondly,by dint of definition of wavelet transformation,the transient effective energy of the phase current measured is extracted at the head of each feeder. Also,the single-phase earth fault location criterion is designed based on the effective energy tracking method. Finally,simulation is undertaken by using PSCAD/EMTDC as simulation platform. The results show that the method can well identify different neutral point grounding mode,transition resistance and the single-phase fault under the fault initial phase angle,as well as enjoys the recognition for the unbalanced distribution network parameters,the high impedance grounding,the situation that sampling currents are mixed with A/D noise and TA measurement error severe on-site working condition.So much so,it provides theoretical guidance for the application of single-phase fault location in medium voltage distribution network.