基于改进阻抗法的有源配电网故障测距算法

Impedance Method Based Fault Location Algorithm for Active Distribution System

考虑有源配电网中分布式电源、分支、中间负荷和电缆-架空线混合线路等元件及各种不确定性因素,如过渡电阻、负荷波动等,提出一种基于相量分析法的改进阻抗型故障测距算法。利用故障点过渡电阻消耗无功功率为零的功率特性,建立适用于各种故障类型、关于故障距离的一元二次测距方程。故障测距算法中,利用FTU同步监测各电源故障前后电压、电流,迭代计算更真实的负荷功率,并提出适用于有源配电网的逐区段故障后电压、电流计算方法。在PSCAD中搭建了改进IEEE 34节点系统模型进行仿真分析,结果表明测距算法具有较高的测距精度和鲁棒性,且能承受一定的负荷波动,受负荷模型影响较小。

Considering distributed generators, branches, intermediate loads, hybrid cable-overhead lines and various uncertain factors in active distribution networks, such as fault resistance and load fluctuation, impedance method based fault location algorithm was proposed. Based on power characteristics of zero reactive power consumed by fault resistance, a quadratic fault location equation applicable to different fault types was established. In the algorithm, FTUs were used to synchronously monitor pre/post-fault voltage and current of each power supply point. Iterative calculation was utilized to obtain more accurate load, and a voltage-and-current calculation method for active distribution network was presented. Case study based on modified IEEE34-bus system shows that the fault location algorithm has high location accuracy and robustness for load fluctuation, and is less affected by load model.