基于正序电流故障分量的有源配电网纵联保护

A Pilot Protection Method Based on Positive Sequence Fault Component Current for Active Distribution Networks

分布式电源就地接入配电网改变了传统辐射状配电网的拓扑与故障特性,对常规的馈线电流保护带来了影响。对此,基于分析不同类型分布式电源在区内外故障时正序电流故障分量的特征差异,提出一种基于正序电流故障分量的有源配电网保护新方法。该方法利用馈线两端正序电流故障分量的幅值比作为动作量,利用正序电流故障分量的相位差构造具有自适应性的制动阈值,能够适应有源配电网在不同场景下的保护需求,且具有灵敏性高、不受负荷影响、耐受过渡电阻能力强等优点。最后,基于所提方法开发了具有保护功能的智能终端样机,动模实验与RTDS测试验证该方法的有效性。

The integration of distributed generators(DGs)changes the topology and fault characteristics of the traditional radial distribution network,which has an impact on the conventional current protection of feeder.Therefore,based on the analysis of the difference of positive sequence fault components(PSFC)current with different types of DGs when a fault occurs inside or outside the protected zone,a novel protection method based on PSFC current was proposed.This method uses the amplitude ratio of PSFC current at the two ends of the feeder as the action parameter,and uses the phase difference of PSFC current to construct an adaptive braking threshold.This method can adapt to the protection requirements of the active distribution network in different scenarios,and has the advantages as high sensitivity,not affected by the load and good performance under the condition of high resistance fault.Finally,based on the proposed protection method,a smart terminal prototype with protection function was developed.Dynamic model tests and RTDS tests verify the effectiveness of the proposed method.