光伏电源接入的配电网短路电流分析及电流保护整定方案

Short-Circuit Current Analysis and Current Protection Setting Scheme in Distribution Network With Photovoltaic Power

根据光伏电源的输出特性,分析了光伏电源接入后,配电网不同位置发生故障时,流过配电网各保护的短路电流受光伏电源输出功率影响的变化规律。发现光伏电源输出功率小于其额定功率时,配电网短路电流水平可能大于光伏电源输出额定功率时的短路电流水平。因此根据光伏电源输出额定功率时的配电网短路电流水平对配电网电流保护进行整定,可能导致电流速断及限时电流速断保护发生误动作。针对这一问题,提出了适应于光伏电源接入的配电网中电流保护的改进整定方案。仿真算例验证了该方案的有效性。

Short-circuit current variation pattern of distribution system with photovoltaic（PV） generation of different capacity under various fault situations is analyzed, based on the fault characteristic of PV power. It is found out that when the output power of the PV generation is lower than the rated power, the short-circuit current of the distribution network may be larger than that when the output power of the PV generation is equal to the rated capacity. Fast current protection and time-critical fast current protection will thus be mis-operated, if the current protection is set with short-circuit current under rated capacity of the PV generation. An improved protection setting method fit for distribution system with PV power is proposed. Simulation verified the effectiveness of the method.