含分布式光伏的配电网双层协调电压优化方法

Coordinated voltage optimization method in distribution network with distributed photovoltaic

当分布式光伏进入极高比例渗透阶段时,配电网电压越限的问题会更加突出。常用方法是调用配电网内多种可调资源改善电压分布,但较少考虑实际工程中馈线层与变电站之间的信息交互。为此,文中提出一种考虑馈线层与变电站双层协调的配电网电压优化方法。在馈线层建立以线路损耗最小为目标的最优潮流模型,经二阶锥松弛求得馈线层首端电压和注入功率,并反馈给上层变电站;在变电站建立以低压侧母线电压调整量最小为目标的调压模型,将调整后的首端电压返回馈线层,更新潮流分布并获得可调资源的调度计划;最后依据扩展的IEEE 33节点配电系统算例,利用Cplex求解,验证了该优化方法在解决配电网电压越限问题的基础上,可以更好地控制电压偏差、减少设备切换次数、提高系统运行的经济性。

When the distributed photovoltaics enters the stage of extremely high proportion penetration,the problem of over-limit voltage in the distribution network becomes more prominent.A variety of adjustable resources in the distribution network are used in the common method to improve voltage distribution,but there is little consideration given to the information interaction between feeder layer and substation in practical engineering.Therefore,a voltage optimization method for distribution network considering the coordination between feeder layer and substation double layer is proposed in this paper.An optimal power flow model with the goal of minimizing the line loss is established in the feeder layer.The voltage at the head of the feeder layer and the injected power of the feeder layer are obtained by second-order cone relaxation,and fed back to the upper substation.A regulating voltage model is established in the substation with the goal of minimizing the voltage adjustment amount of PCC,and the adjusted voltage is returned to the feeder layer to update the power flow distribution.Then,the scheduling plan of adjustable resources are obtained.Finally,the extended IEEE 33-node power distribution system is taken as an example.The Cplex optimization solver is used to verify that the method can control the voltage and reduce the number of switching equipment.The economy of system operation on the basis of solving the distribution network voltage over-limit problem is improved.