低压配电网分散无功补偿与扩大线径协调优化计算

Coordinated Optimization Calculation of Distributed Reactive Power Compensation and Line Diameter Expansion in Low Voltage Distribution Network

针对低压配电网馈线末端节点电压偏低的问题,提出了低压配电网分散无功补偿与扩大线径协调优化计算模型。目标函数综合考虑了安装无功补偿装置和更换导线的投资成本以及降低配电网损耗的经济效益,约束条件包括配电网运行约束,以及无功补偿点补偿容量和扩大线径支路截面积的上下限约束。采用凸松弛技术对优化模型中的整数变量进行连续化处理,并结合问题特点降低需要引入整数变量的数目。根据低压配电网潮流计算结果选择电压损耗大的支路作为扩大线径候选线路,同时以所有负荷节点作为候选无功补偿点,计算得到分散无功补偿与扩大线径的协调优化方案。以某个实际低压配电台区为例,计算结果验证了所提出方法得到的协调优化方案比单纯无功补偿方案具有更高的经济效益,电压质量也更好。

Aimed at the problem of slight low node voltage at the end of feeder of in low voltage distribution network, the coordinated optimization calculation model for distributed reactive power compensation and line diameter expansion is proposed. The investment cost for installing reactive power compensation device and replacing line and the economy efficiency of reducing network loss are comprehensively considered in the objective function. The constraints include various operation constrain of distribution network, upper and lower constraints of compensation capacity of the reactive power compensation point and expansion cross section area of line path. The convex relaxation technology is used to process continuously the integer variables in the optimization model and the number of integer variables is reduced by the characteristics of the problem. The branch with high voltage loss is selected as the candidate line of diameter expansion line in accordance with flow calculation of low voltage distribution network and, at the same time, all the load is taken as candidate reactive power compensation point,and the coordinate optimization proposal is obtained of distributed reactive power compensation and line diameter expansion is obtained by the calculation. A certain actual low voltage distribution network is taken as an example.It is verified through the calculation result that the coordinated optimization proposal obtained by the proposed method has higher economy efficiency and better voltage quality than those of pure reactive power compensation proposal.