基于采样值相关度的广域后备保护算法

摘要

为解决传统后备保护整定配合复杂,发生CT断线时无法识别故障等问题,提出了一种基于采样值相关度的广域后备保护算法.该算法充分利用电网的电压、电流信息,以关联IED的采样值相关度构成保护判据.发生CT断线时,通过关联矩阵进行关联IED搜索,根据关联IED的相关度和虚拟CT的相关度大小关系区分线路故障和母线故障.该算法对采样同步精度要求低,发生CT断线时依然能正确识别并切除故障元件.最后基于PSCAD搭建IEEE 3机9节点系统进行仿真验证,结果表明:该算法能准确识别线路和母线上的各种类型故障,具有良好的动作性能.%In order to solve the problems of setting and coordination of the traditional back-up protection and its malfunction when CT breaks,a wide area back-up protection algorithm based on the correlation of sample value is proposed.The algorithm makes full use of the voltage and current information of the power grid,and the protection criterion is constituted based on the correlation of the sample value of the associated IEDs.Associated IEDs is searched through the associated matrix when CT breaks.The fault element is identified according to the correlation of the associated IEDs and the correlation of the virtual CT.This algorithm is still effective when synch precision is low and CT breaks.Finally,an IEEE 3-machine and 9-bus system is constructed by PSCAD simulation verification,the results of the correlation degree of sample value show that the proposed algorithm can identify various types of faults on line and bus,and has good operational performance.