基于电流综合矢量的高灵敏启动元件

对继电保护启动元件的一个基本要求是能反映各种故障,并且灵敏度要高。现有微机保护装置的启动元件存在着高阻接地和缓慢发展性故障情况下灵敏度不足的缺点,振荡情况下可能产生误启动,并且不能识别振荡中再发生故障的情况。本文提出一种基于综合矢量的新算法,利用同时刻的三相电流瞬时值构成综合矢量,根据正常与故障波形包络线的变化趋势来识别故障。EMTDC和动模数据仿真表明:这种算法计算量小,数据窗短,不受系统频率偏差的影响,能灵敏反映各种故障并且在高阻接地故障情况下不需要增加辅助判据就能可靠地启动保护,具有工程实用价值。

A New High-Sensitivity Starting Element Based on Current Comprehensive Vector

One basic requirement to starting element of relay protection is that it has high sensitivity and can reflect all kinds of faults.Now the commonly used starting elements are insensitivity to the slow expansibility faults,and high earth resistance faults are easily affected by power system swing.The paper presents a new starting algorithm based on comprehensive vector,which can pick the instantaneous currents of three phases simultaneously to form the amplitude of comprehensive vector and discriminate the fault according to the waveforms tendency of normal condition and fault.Simulation of EMTDC and experimental results indicate that the algorithm has small calculation and short data window and can bear the system frequency excursion and start protection in the case of slow developing faults or high earth resistance faults without any assistant criteria.