基于重合相有功功率的配电网永久性故障识别方法

Permanent Fault Identification Method for Distribution Networks Based on Reclosing-phase Active Power

针对盲目重合于永久性故障会给配电网带来二次冲击等问题,提出一种基于重合相有功功率的配电网永久性故障识别方法。首先,建立了配电网分相重合时的分析模型,推导了不同中性点接地方式下瞬时性和永久性故障时的重合相有功功率表达式,得到了不同故障性质下有功功率的差异;其次,构建了基于有功功率的永久性故障识别判据,分析了过渡电阻、负荷大小等因素的影响,得到了所提方法在不同中性点接地方式系统中的适用范围并提出了分相重合策略;最后,通过PSCAD/EMTDC仿真结果验证了理论分析正确,以及所提永久故障识别方法耐过渡电阻能力较强。

A permanent fault identification method for distribution networks based on the reclosing-phase active power is proposed to address the issue of blindly reclosing with permanent faults causing secondary impacts on the distribution network.Firstly,the analysis model of split-phase reclosing in distribution network is established.The expressions of active power of reclosing phase under instantaneous fault and permanent fault with different neutral grounding modes are derived,and the differences of active power under different fault properties are obtained.Secondly,the criterion of permanent fault identification based on active power is constructed.The influence of transition resistance,load capacity and other factors is analyzed.The application scope of the proposed method in the systems with different neutral grounding modes is obtained and the split-phase reclosing strategy is proposed.Finally,the PSCAD/EMTDC simulation results verify that the theoretical analysis is correct,and the proposed permanent fault identification method has strong ability to resist transition resistance.