利用充电保护实现短引线保护的可行性研究

Feasibility Study of Short Lead Protection with Charging Protection

针对3/2接线的500 kV升压站,当某台发电机停运后,发变组与系统解列,但出于电网安全考虑,调度部门要求断开主变压器高压侧出线隔离开关,恢复升压站内所停运机组的出线断路器为完整串运行。此时500 kV出线断路器至主变高压侧出线隔离开关之间的短引线处于带电运行状态,发变组保护装置中的发变组差动保护就必须投运,这给发变组保护装置定检工作带来了很大的安全隐患。通过认真细致地调查研究,并结合现场的实际情况,综合考虑电网设备及发变组保护装置定检工作的安全性,确定在不新增短引线保护装置的前提下,利用断路器保护装置的充电保护实现短引线保护功能,以确保电网设备的安全、经济、稳定运行。

For the 500kV booster station with 3/2 wiring,when a generator is out of service,the generator set and the system are untied.However,for the sake of power grid safety,the dispatching department requires that the high voltage side outlet disconnector of the main transformer be disconnected,and the outlet circuit breakers of the units shut down in the booster station be restored to complete series operation.At this time,the short lead between the 500 kV outlet circuit breaker and the main transformer high-voltage side outlet isolating switch is in live operation.The generator-transformer differential protection in the generator-transformer protection device must be put into operation,which brings great safety hazards to the regular inspection of the generator-transformer protection device.Through careful investigation and research,combined with the actual situation of the site,and considering the safety of regular inspection of power grid equipment and generator transformer unit protection device,it is determined that the charging protection of circuit breaker protection device can realize the short lead protection function without adding new short lead protection device,so as to ensure the safe,economic and stable operation of power grid equipment.