某220 kV内桥接线变电站线路保护改造方案

A Scheme to Add Transmission Line Relay at a 220 kV Internal Bridge Wiring Substation

220 kV内桥接线变电站作为终端变,通常不配置线路保护,靠对侧电源端线路保护切除故障。如果是主变低压侧区内故障,在高压侧开关失灵情况下,对侧保护距离Ⅱ段或Ⅲ段动作,这样主变承受故障电流时间增长。为了实现全线速动,某变电站一回220 kV线路增设双套线路保护。同时为了减小线路开关失灵时短路电流对主变的冲击,线路开关配置失灵保护。在线路保护改造过程中遇到了互感器选型、开关保护选型和操作箱选型等问题,文中给出了处理方案。

Usually there is not transmission line relay disposition at a 220kV internal bridge wiring terminal substation.It depends on transmission line protection at the opposite side substation.When a ground fault occurs on low-voltage side,if high-voltage side switch refuses to open,it depends on backup distance protection at the opposite side substation.To improve fast-trip performance and protection the main transformer,two transmission line relays are added at a 220kV substation.Current transformer and voltage transformer selection,failure protection relay selection and operation box selection problems are discussed in this paper.