光伏接入配电网线路故障特征及保护方案的研究

Research on line fault characteristics of photovoltaic power connected to distribution network and its protection scheme

光伏系统接入配电网后,配电网供电模式发生变化,导致配电网部分继电保护设备不能正确动作。根据储能充放电原理,在光伏输出直流侧并入储能模块抑制光伏功率波动,确保配电网接受光伏功率保持恒定,进而提出适用于光伏接入配电网线路电流保护的整定方法,该方法能够解决光伏接入点反向出口短路电流值大小随光伏输出功率波动的问题。在PSCAD/EMTDC中建立了储能型光伏接入10 k V配电网算例模型,通过仿真验证了该方法的正确性与有效性。

The power supply mode of distribution network changed when PV system was connected to the distribution network,which led to incorrect operation of some protection devices. Energy storage module was incorporated in at the DC side of photovoltaic to restrict fluctuation of PV output based on the charging and discharging principle of energy storage, and then a configuration scheme of current protection circuit for the photovoltaic connected to distribution network was put forward. This method could solve the problem of the photovoltaic coupling point reverse output short-circuit current value changing with the PV output power fluctuation. An example model of 10 kV distribution network with energy storage and photovoltaic system was established in PSCAD/EMTDC,the simulation verified correctness and effectiveness of the method.