基于配电网柔性接地控制的故障消弧与馈线保护新原理

为解决中性点非有效接地配电网中长期存在的单相接地故障消弧与保护难题,提出基于零序电压柔性控制的配电网接地故障消弧与保护新原理。在配电网发生接地故障的初始时刻,通过脉宽调制(pulse width modulation,PWM)有源逆变器注入零序电流补偿接地故障全电流,实现对零序电压的控制,促使故障点电压为0,实现瞬时故障100%消弧。接地故障发生后,经一定延时,控制电流注入,增大故障残流,精确测量零序电压和各馈线零序电流变化量,实现接地故障的动态感知和可靠保护。该技术有望降低故障建弧率,减少故障停电时间,促进配电网智能化发展。

Novel Principle of Faults Arc Extinguishing ＆ Feeder Protection Based on Flexible Grounding Control for Distribution Networks

To solve the problems of ground faults arc extinguishing and feeder protection for distribution networks with non-effective grounding,a novel flexible grounding theory and practice were proposed in this paper.When a single-phase-to-ground fault occurred,a zero-sequence current was injected by pulse width modulation(PWM) inverter to full-compensate the fault current,and the value of fault phase voltage was controlled to be zero,the fault arc was thus extinguished.With little time delay,the injecting current was adjusted and the fault current was changed.The zero sequence voltage and currents of distribution network were accurately measured,and the fault feeder was dynamically detected and protected.The flexible grounding technology can extinguish grounding faults arc,reduce power outage time and make the system be smarter.