一种光伏电站送出线路自适应距离保护方法

摘要

针对光伏电站送出线路光伏电站侧距离保护受过渡电阻影响的问题,提出一种自适应距离保护方法.分析比较了过渡电阻对传统双侧电源线路和对光伏电站送出线路距离保护的影响不同原理,根据过渡电阻影响距离保护测量阻抗偏移相量图的几何关系推导出了一种新的自适应保护判据,该判据加入了自适应整定系数,且自适应整定系数仅依赖于附加阻抗倾斜角的获得.通过公式推导获得了倾斜角与故障线路两侧电流幅值比和相位差的函数关系,从而提出一种光伏电站送出线路自适应距离保护方法.最后,在Dig SILENT/Power Fac-tory软件中仿真对比了传统距离保护和改进距离保护下不同故障类型下光伏电站侧距离保护动作情况.仿真分析结果显示,所提方法极大地改善了过渡电阻对光伏电站送出线路距离保护的影响,从而验证了所提方法的可行性.%An adaptive distance protection method is proposed for the problem that photovoltaic (PV) power station side distance protection on the transmission line of PV power station affected by the transition resistance. Comparative analysis is conducted on the different influence principles of transition resistance on the traditional bilateral power lines and the transmission line of PV power station distance protection. A new adaptive distance protection criterion is de-rived from the geometric relationship of the phase diagram of distance protection measured impedance offset affected by transition resistance and adaptive tuning factor based on the acquisition of additional impedance inclined angle is add-ed in the criterion. The function relation between the inclined angle and the current amplitude ratio and the phase difference between the two sides of the fault line is derived by formula derivation, and a new method of adaptive dis-tance protection for the transmission line of PV power station is proposed. Finally, in Dig SILENT/ Power Factory soft-ware, comparative simulation research is conducted on the action situation of distance protection of the PV power sta-tion side with different fault types under both traditional distance protection and improved distance protection. The simulation results show that the proposed method can greatly improve the effect of transition resistance on the distance protection of the transmission line of PV power station, and therefore, the feasibility of the proposed method is veri-fied.