含分布式电源的合环配电网保护策略

Protection Strategy for Closed-Loop Distribution Network with Distributed Generation

为充分发挥含分布式电源(distributed generation,DG)合环运行配电网高可靠性和促进新能源消纳等优势,研究了其继电保护策略。分析了解环定时限过流保护和方向定时限过流保护原理和动作特性,基于投资经济、有效隔离故障原则,提出了一种针对含DG合环配电网的纵联过流保护策略,并给出了纵联通信方式的选择方法。仿真分析了所提策略应用的保护动作和故障隔离情况,验证了其有效性。结果表明:纵联过流保护策略无需上下游保护间的动作时限配合,可在很短时间内隔离合环配电网任一处故障,且隔离范围小,至多损失一条母线负荷,不切除DG,有效提升了合环配电网供电可靠性和DG利用率。

In order to give full play to the advantages of the closed-loop distribution network with distributed generation(DG),such as its high reliability and effect in promoting the absorption of renewable energy,its relay protection strategy is studied.The principle and operation characteristics of the unlooping over-current protection and the directional overcurrent protection are analyzed.Based on the principle of economic investment and effective fault isolation,a pilot overcurrent protection strategy for the closed-loop distribution network with DG is proposed,and the selection method of the pilot communication mode is given.The effectiveness of the proposed protection strategy is verified by simulation.The results show that the proposed strategy can isolate the faults in a very short time,and the isolation range is small.At most,only one bus load is lost,and DG is not removed,which effectively improves the reliability of power supply and DG utilization of closed-loop distribution network.