含逆变型分布式电源的配电网正序综合阻抗纵联保护

Pilot protection of positive sequence component integrated impedance for distribution network with inverter interfaced distributed generator

为解决逆变器控制策略对含逆变型分布式电源的配电网的故障特性的影响问题,提出了一种基于正序分量综合阻抗的纵联保护新原理。该原理利用线路两端正序电压相量之差与线路两端正序电流相量之和的比值构成正序分量综合阻抗。区内与区外发生故障时,正序分量综合阻抗的幅值变化明显,据此可以区分线路上的内部和外部故障。新原理特征量明显,容易整定,不受分布式电源控制策略的影响,抗过渡电阻能力强。PSCAD仿真验证了该原理的有效性。

In order to solve the influence of the inverter control strategy on the fault characteristics of the distribution network with Inverter Interfaced Distributed Generator(IIDG),a new principle of pilot protection based on positive sequence component integrated impedance is proposed.The principle uses the ratio between the difference of two terminals positive sequence voltage phasor of the transmission line and the sum of the two terminals positive sequence currents phasor of the same transmission line to form a positive sequence component integrated impedance.When the faults occur in external or internal area,the amplitude of the positive sequence component integrated impedance varies obviously,so that the internal and external faults on the line can be distinguished.The new principle has obvious characteristics,such as easy tuning,free from the influence of distributed generation control strategy,and strong resistance to transition resistance.The validity of the principle is verified by PSCAD simulation.