基于暂态特征模量分析的配网三芯铠装电缆故障感知与测距

Fault Sensing and Location of the Three-core Armored Cables in Distribution Network Based on the Analysis of the Fault-featured Transient Moduli

配网三芯铠装电缆各相导芯、金属屏蔽层和铠装层之间存在显著的电磁耦合,其故障暂态分析较为复杂。为了实现对配网三芯铠装电缆故障感知,首先提出暂态信号时域解耦矩阵的一般计算方法,定义解耦后的新模量,筛选出能够有效反映故障的特征模量。然后,分析故障前后特征模量的状态变化,建立三芯铠装电缆故障辨识判据。最后,基于暂态模量在电缆中的传播特征,考虑实际测量条件,利用暂态模量到达时刻和频率分量幅值比,构建了4种故障测距方案。利用PSCAD/EMTDC搭建配网三芯铠装电缆模型并进行故障仿真。计算结果表明:所提方法能有效辨识电缆故障,实现不同故障条件下的故障精确测距。

Significant couplings exist in the core-conductor,sheath and armor of the distribution three-core armored cable,which adds to the difficulty of transient fault analysis.First,to achieve fault sensing on the three-core armored cable in the distribution network,the general steps for calculating the decoupling matrices in time domain were proposed.The new decoupled moduli were defined.The fault-featured moduli,effectively reflecting the faults,were selected.Then,the variation of the fault-featured moduli before and after the fault was analyzed.A criteria for identifying the fault in the three-core armored cable was proposed.Finally,based on the propagation characteristics of the moduli in the cable,four fault location schemes considering the actual measurement conditions were constructed by using the arrival time and frequency component amplitude ratio of the fault-featured moduli.The model of the distribution three-core armored cable was created by PSCAD/EMTDC and various fault simulations are conducted.The results demonstrate that the proposed method can effectively identify and locate the cable faults in different conditions with high accuracy.