基于柔性多状态开关的主动配电网双层负荷均衡方法

分布式电源(DG)的大量接入使得配电网源荷不确定性与随机性增大,而柔性多状态开关(FMS)的应用使得供区间互联不再受制于电压等级和相位,主动配电网(ADN)多供区联合优化运行将成为新常态,也为改善负荷不均衡现象、提高供电水平提供了基础.利用FMS灵活互联的特点,以供区层和馈线层负荷均衡指数加权最小为目标函数,建立了ADN双层嵌套负荷均衡模型,并采用改进粒子群和二阶锥规划的混合优化算法求解网络重构拓扑方案与FMS出力.整体算法外部对合环配电网进行简化和等效,减小网络重构的粒子群算法的粒子规模,加快计算速度;内部采用最佳等距分段线性逼近法(OEPLAA)对目标函数进行线性化,将FMS出力优化问题进行二阶锥转化.最后,通过某实际配电网对所提出的负荷均衡方法进行了分析和验证.

Bi-layer Load Balancing Method in Active Distribution Network Based on Flexible Multi-state Switch

With the integration of a large number of distributed generators (DGs) into the network, the uncertainty and randomness of the output of the supply and load in the distribution network gradually increase. The application of flexible multi-state switches (FMSs) enable the interconnection between supply areas without restriction of voltage levels and the phases. Therefore, the joint operation optimization of multi-supply areas in active distribution network (ADN) will become a new normal situation, which provides the foundation for the improvement of the load unbalance condition and the voltage level. By using flexible interconnection characteristics of the FMS, taking the weighted minimum of the supply area and feeder load balance indices as the objective function, the bi-layer embedded load balancing model for ADN is established, and a hybrid optimization algorithm consisting of improved particle swarm optimization (PSO) and second-order cone programming is used to solve the problem of network reconfiguration topology and FMS output. First, the closed-loop distribution network is simplified and equivalent to decrease the particle scale during the network reconfiguration of PSO algorithm in the outer layer of the whole method to speed up the calculation. In the inner layer, the objective function is linearized using optimal equidistant piecewise linear approximation algorithm (OEPLAA), by which the problem of output optimization of FMS can be transformed into a second-order cone programming problem. Finally, the proposed double-layer load balancing method is analyzed and verified through an actual distribution network.