某500kV母线保护失灵元件误动分析

随着光耦元件在综合自动化变电站二次设备中的广泛应用,其工作特性也需要引起特别关注。通过一起失灵保护误动实例,分析了因为较长并接电缆对地存在的电容效应,在直流系统正接地瞬时,电容放电导致光耦元件误导通的动作机理,并提出了用较大功率(8W)中间继电器重动的改进措施,为同类型母线失灵保护提供了有益的借鉴。

Analysis of failure element maloperation of a 500 kV bus protection

Along with the extensive application of optocoupler element in the secondary equipment of integrated automatic substations,its operating characteristic also needs much attention.In this paper,an application example of failure protection maloperation is given.It analyzes the action mechanics of the electric capacity discharge.The optocoupler element will misdirect positive pole of DC System grounding,because of the existent electric capacity effect of a long electric cable to the ground.It puts forward the improving measure of using a higher power(8W) intermediate relay restart,and provides useful reference for same category failure protection of the bus.