基于相关度的发电机采样值差动保护  

GENERATOR DIFFERENTIAL PROTECTION BASED ON CORRELATION COEFFICIENTS OF SAMPLED CURRENT VALUES

作　　者：肖仕武[1] 刘万顺[1] 黄少锋[1] 

机构地区：[1]华北电力大学(北京)四方研究所,北京市100085

出　　处：《电力系统自动化》2003年第17期59-63,共5页Automation of Electric Power Systems

摘　　要：提出利用发电机机端和中性点侧电流的采样值波形的相关度来区分内部相间故障和外部故障。分析了数据窗的长度 ,两侧电流的幅值、相位 ,以及采样的同步对相关度的影响。利用短数据窗来连续计算相关度 ,并根据多点相关度的情况可以清楚地区分内部相间和外部故障。提出了基于相关度的发电机采样值完全纵差保护新判据 ,理论分析和仿真验证了该判据能够快速、可靠地切除内部故障 ;外部故障时 ,即使电流互感器严重饱和也不会误动。基于这种方法的判据能够在小于1/ 4周期内可靠动作 。This paper presents a new way to distinguish internal phase to phase faults and external faults based on correlation coefficients of sampled current values at neutral and terminal. The effect of the data window length, current magnitude, phase difference and sampling synchronization on correlation coefficients is analyzed. When utilizing short data window to calculate some correlation coefficients continuously, it is very clear to distinguish internal phase to phase faults and external faults based on these correlation coefficients. This paper also presents a new generator differential protection criterion based on correlation coefficients of sampled current values. Theoretical analysis and simulation results prove that the new criterion can clear internal fault very fast and reliably and wouldn't maloperate when external fault occurs, especially when one current transformer is saturated. The new protection can trip in less than one of fourth circle time, and is not affected by frequency variation.

关 键 词：发电机保护 采样值差动保护 相关度 电流互感器 饱和 

分 类 号：TM772[电气工程—电力系统及自动化]