母线保护电压闭锁元件误动分析

220kV母线保护在变电站内属十分重要的元件保护，一旦动作则会跳开数条线路。通常在保护中用电压闭锁元件防止保护误动，只有电压满足动作条件而开放元件后，保护才能动作。本文通过一套保护出现电压开放的现象，分析了电压元件采用的算法，阐述了各种算法的优缺点，提出了改进意见。

Busbar protection for blocking voltage element malfunction

220 kV bus protection is an important element protection in the substation.It prevent from malfunction by the blocking voltage element,which unblock busbar protection when line-line voltage is lower than low-voltage set value or zero-sequence voltage is higher than zero-sequence voltage set value.In this paper,merits and faults of different blocking voltage algorithms are presented.Finally,an improved blocking voltage algorithm is proposed.