基于串补线路出串运行的保护配合方法

Protection Coordination Method Based on Out-series Operation of Series Compensated Line

摘要:

为解决短路电流越限问题，四川电网常采用线路出串运行方式，带串补线路出串运行时，延伸侧线路发生故障会对串补系统造成冲击损害，同时串补电容器组的存在可能导致线路跳闸时线路潜供电流和暂态恢复电压超过原有水平，导致线路跳闸后断口发生重击穿、重合闸失败、故障切除推迟甚至导致断路器的损坏。文中提出一种带串补线路出串运行的保护配合方法，在带串补线路侧加装远跳装置接收延伸线路跳闸命令，实现延伸线路联跳串补功能，解决延伸线路跳闸后串补电容导致潜供电流和暂态恢复电压增大的问题，同时避免了电容器组遭受冲击损害。现场试验表明，在延伸侧单相瞬时故障时，可正确快速旁路串补，并在线路重合后重投串补；在延伸侧相间故障时，三相旁路串补，满足工程应用。研究成果可解决串补线路出串运行的保护适应性问题。

Abstract:

In order to solve the over-limit problem of short-circuit current, Sichuan power grid often adopts the scheme of out-series operation. When the line with series compensation（SC）is in out-series operation, the failure of the extension side line will cause impact damage to the series compensation system. At the same time, the existence of SC capacitor bank may cause the line submersible current and transient recovery voltage to exceed the original level when the line is tripped, resulting in heavy breakdown of the fracture after the line tripping, which will cause system overvoltage reclosing failure, delayed fault removal and even damage to the circuitbreaker. A protection coordination method for out-series operation of line with SC is proposed, that is to install a remote transmission device on the side of line with SC to receive the tripping command of adjacent lines so as to achieve the intertrip between adjacent lines and SC lines, which can suppress the potential supply current and transient recovery voltage caused by residual voltage of capacitor after tripping of adjacent lines, and also ensure that the capacitor bank is not damaged by impact. Field tests show that in case of a single-phase transient fault on the extension side, the SC can be bypassed correctly, and the series compensation can be re-opened after the line is overlapped; when the phase-to-phase fault occurs on the extension side, the SC can be bypassed permanently, which meets the engineering application. The research results can provide a certain reference for protection adaptability of out-series operation of series compensated line.