计及智能软开关与分布式电源调节能力的配电网两阶段无功优化

Two-stages Reactive Power Optimization of Distribution Network Considering Regulation Capacity of SNOP and Distributed Generation

安装于配电网联络线上的智能软开关(soft normally open point,SNOP)除了能够传输有功功率外,还能够调节无功输出以实现对电压水平的支撑。配电网的无功优化需要综合考虑有载调压变压器(on-load tap changer,OLTC)的分接头、SNOP与分布式电源(distributed generation,DG)的无功输出。针对这一多控制变量的求解难题,首先建立了以系统有功网损和与上级电网无功交换功率最小为目标函数的优化模型,该问题属于带时间耦合的混合整数规划问题。然后,提出了基于粒子群算法的两阶段无功优化方法,第一阶段忽略时间耦合性,通过聚类算法得出OLTC动作方案,第二阶段获得SNOP与DG的组合状态。最后,以改进的IEEE 33节点系统为算例,计算结果表明考虑SNOP与DG灵活运行的配电网无功优化满足网损减小、无功就地平衡的要求。

In addition to being able to transmit active power, Soft Normally Open Point(SNOP) installed on the tie line of distribution network can also adjust the reactive output to support the voltage level. The reactive power optimization of distribution network requires a comprehensive consideration of the tap of on-load tap-changer(OLTC), the reactive output of SNOPs and Distributed Generations(DGs). Aiming at the problem of solving multi control variables, an optimization model with the minimum system active power loss and reactive power exchange of upstream grid as the objective function is established, which belongs to the mixed integer programming problem with time coupling. Then, a two-stage reactive power dispatching method based on particle swarm optimization is proposed. The time coupling is ignored in the first stage, and the OLTC action plan is obtained through the clustering algorithm. The combined state of SNOPs and DGs is solved in the second stage. Taking the improved IEEE 33-node system as case study, the calculation results show that the reactive power optimization of the distribution network considering the flexible operation of SNOP and DG meets the requirements of network loss reduction and reactive power local balance.