不受电力系统振荡影响的距离保护

Distance Protection That Insensitive to Power Swing

距离保护被广泛应用于电力系统中,现有距离保护核心元件——距离继电器不同程度地存在缺陷,导致系统发生振荡时保护误动作或者性能下降,常用的距离继电器必须配合振荡闭锁元件使用。因此,以保证保护正确动作为前提,提出一种不受系统振荡影响的距离保护。该保护基于改进的多相补偿继电器构成,配合闭锁元件以解决振荡中发生区外故障时多相补偿继电器的不正确动作问题。所提出的距离保护对于故障、单纯振荡无故障、振荡过程中发生不对称故障以及对称短路故障都有正确的反应能力,且具有判断故障类型和故障相别、分相跳闸的能力。PSCAD仿真结果证实了所提距离保护的有效性。

Distance protection is wildly applied in power systems. Distance relay is the core element of distance protection. The existed distance relays have some disadvantages that make the distance protection incorrectly operate during power swing or make the performance of distance protection poorer. This paper proposed a distance relay insensitive to power swing. The relay is based on modified multiphase compensated distance relay and works with a block module to avoid the incorrect operation during external faults in power swing. The relay can operate correctly in the condition of fault, power swing or fault with power swing. It can distinguish the fault type and phase, and trip out the faulty phase. The effectiveness of the proposed relay was verified by the simulation results of PSCAD.