配电网柔性接地暂态过程分析与优化方法研究

Research on Transient Process Analysis and Optimization Method of Flexible Grounding in Distribution Networks

针对传统配电网谐振接地方式无法实现暂态过程补偿的问题,通过对新型柔性接地暂态过程进行分析,提出了一种基于柔性接地方式的暂态响应优化方法。当发生单相接地故障后,通过有源逆变器向配电网中性点注入有功分量及无功分量的补偿电流,从而优化单相接地故障的暂态响应。理论分析与仿真结果表明,补偿电流有功分量可加快暂态过程的衰减并抑制瞬态过电压的幅值;无功分量则用于补偿消弧线圈的暂态电流,由此降低建弧率或使得电弧快速熄灭,减小由瞬时性故障发展成为永久性故障的概率。该暂态响应优化方法能够实现单相接地故障暂态期间柔性消弧与可靠自愈,进一步提升了配电网的运行可靠性。

In order to solve the problem that the way of resonant grounding can not be adopted to realize the compensa tion of the transient process, a transient response optimization method based on flexible grounding was proposed by analyzing the transient process. When single-phase grounding fault occurs, the compensation current of active and reac tive components is injected into the neutral point of distribution network by inverter to optimize the transient response. Theoretical analysis and simulation results show that the active component of compensation current can accelerate the at tenuation of transient process and restrain the amplitude of transient overvoltage;the reactive current component is used to compensate the transient current of arc-suppression coil. The optimization method can be adopted to reduce the proba bility of establishing arc and the possibility from instantaneous fault to permanent fault or rapidly extinguish arc. Therefore, the optimization method can be adopted to achieve flexible arc suppression and reliable self-healing during transient period of single-phase grounding fault and to improve the operation reliability of distribution network.