基于机会约束凸松弛的分区随机无功备用优化方法

Abstract

针对含不确定性的新能源大量接入和系统无功功率的区域特性,提出一种基于电压控制分区的区域随机无功备用优化方法。首先采用基于凝聚聚类和模块度指标对系统进行无功分区,然后利用松弛方法将含随机性的优化模型转换为确定型,最后提出基于无功分区的逐次无功备用优化方法。若干仿真算例的分析证明,机会约束凸松弛方法可较准确地转换机会约束,而分区优化方法将高维的无功备用问题转换为低维的子问题,提高了算法的寻优效率,获得的优化方案可显著提高区域无功备用和电压稳定裕度,降低系统运行的风险,并对N-1故障后系统的电压水平也有一定改善作用。

In order to address the uncertainties of sustainable energy integration and regional characteristics of reactive power, a stochastic optimal reactive reserve dispatch method based on voltage control area is proposed in this paper. At first, agglomerative clustering and modularity index are employed to find the system reactive area. And then the convex relaxation method is adopted to transform the stochastic optimization model into deterministic. Finally, a successive regional optimal reactive reserve optimization method is proposed. Several test cases demonstrate that convex relaxation is able to convert chance constraints accurately. The proposed method transforms the high dimensional original optimization problem into several regional sub-problems with low dimension, which leads to high computational efficiency. The dispatch scheme has significantly enhanced the reactive power reserve and voltage stability margin. The operational risk of the power system is also decreased, which also enhances the voltage profile of N-1 scenarios.