提高变电站继电保护可靠性的措施

分析母线保护死区和变压器保护死区常见的故障，并提出相应的改进措施。对于出线处断路器与其电流互感器间故障的可行措施为增加启动光纤保护远跳回路中的“永跳继电器启动远跳”连片，并在本侧进行检修时退出该光纤通道或进行光纤自环；对于母联断路器与其电流互感器间故障，增加一个CT3以避免双母线全部跳闸；对于变压器保护死区故障，建议在联跳主变压器三侧回路中去掉断路器辅助接点；并在回路中增加一块连片（LP2）以防止在保护设备检修过程中误启动联跳主变压器三侧。

Measures to Enhance the Relay Protection Reliability in Substations

The common faults about death zones of the bus and transtormer protection are analyzed, and the corresponding measures are presented. For the death zone between breaker and current transformer in the feeding line, the measure is to add a linking tablet 'Triple-Trip Relay Starts Remote Trip' into the starting-remote-trip circuit of the optic-fibre protection, and the fibre will quit or make self-linked as the relay protection equipment being tested. For the death zone of buses-linker, CT3 is added to avoid double buses both losing voltage. To overcome the death zone problem of transformer protection, the measure is to delete the auxiliary contact of breaker in the circuit of tripping transformer's three sides while to add a linking-tablet 'LP2' into the circuit to prevent the mistake of starting tripping transformer's three sides during the orderly maintenance.