消弧线圈并联小电阻接地方式下的行波故障测距

中国10～35 kV中性点经消弧线圈接地的中压配电网越来越多地采用消弧线圈与小电阻并联的方案。在发生永久性单相接地故障后投入并联小电阻,使故障电流增大,让保护装置可靠动作并断开故障线路。因此,在其基础上进行单相接地故障的测距技术研究极具发展前景和必要性。并联小电阻后将产生电流行波并在到达故障点后反射,反射电流行波幅值较大、特征明显。文中提出了利用投入并联小电阻产生的电流行波来进行故障测距的方法。深入分析了电流行波在线路上的传输特性,以及利用电流行波零模分量和线模分量进行故障测距的单端测距策略。针对配电网的特点,研究了架空线、电缆混合线路的解决方案以及利用多个检测装置信息的综合测距技术。最后,ATP/EMTP软件的仿真结果证明了所提出的故障测距方法的准确性和实用性。

Traveling Wave Fault Location for Arc-suppression Coil in Parallel with Low Resistance Grounding Mode

The scheme that arc-suppression coils are in parallel with low resistances is increasingly utilized in 10~35 kV medium voltage distribution networks in China whose neutral node is grounded through arc suppression coil. The parallel low resistance will be connected after a permanent single-phase-to-ground fault occurs, which increases the fault current and the protection device is reliably operated to trip the fault line. Therefore, the researches on the fault location technology of single-phase-to-ground fault on the basis of the above have great development prospects and necessity. After the parallel low resistance is connected, the current traveling wave is generated and reflected when reaching the fault point. The current traveling wave has high amplitude and obvious characteristics. Based on these features, this paper proposes a fault location method using the current traveling wave generated by the parallel low resistance. The propagation characteristic of the current traveling wave along the line is analyzed in deep and the single terminal fault location method based on the zero-mode and aerial-mode components is presented. According to the characteristics of distribution network, the solutions of hybrid networks with overhead lines and cables as well as the integrated fault location technology using multiple detection devices are studies. Finally, the simulation results of ATP/EMTP software confirm the accuracy and practicality of the proposed fault location method.