基于风险控制的PSCOPF改进模型及交替迭代算法

计算效率低和计算结果过于保守是困扰传统预防性安全约束最优潮流(PSCOPF)应用的2个关键难题。针对这些问题,提出一种新的具有可控风险度的改进模型及交替迭代算法。根据电力系统实际运行控制存在偏差的特点,在发电机有功和无功源电压等变量的基础上引入偏差量;以偏差量的平方和最小作为综合风险指标,构造电压互补约束,将原始大规模PSCOPF问题分解为故障数较少的PSCOPF和约束潮流2个子问题。子问题之间采用交替迭代的方式计算,获得不可控故障集和可控故障集,进而得到整个问题的解。IEEE 118、300节点标准系统和某703节点、241个预想故障实际系统的测试结果表明,所提模型及算法在不降低系统安全性的前提下具有良好的经济性和较高的计算效率;与传统模型的集中式计算方法相比,其占用内存可减少80%,串行和并行加速效果分别在5倍和10倍以上。

Improved PSCOPF model based on risk management and alternative iteration algorithm

The low computational efficiency and excessively-conservative results of PSCOPF(Preventive Security-Constrained Optimal Power Flow) restrict its application, aiming at which, an improved model with controllable risk and an alternative iteration algorithm are proposed. According to the practical operation of power system, deviations are introduced to the operating variables, such as active power of generator, voltage of reactive source, etc. The minimum square sum of deviations is taken as the comprehensive risk index to construct the complementary voltage constraints for decomposing the original large-scale PSCOPF problem into a PSCOPF problem with less faults and a constrained power-flow problem. Alternative iteration is carried out between two problems to obtain an uncontrollable fault set and a controllable fault set for solving the entire problem. The results of tests for standard IEEE 118-bus system, IEEE 300-bus system and an actual 703-bus 241-fault system show that, without system security debasement, the proposed model and algorithm has better economy and higher computation efficiency, and compared with the centralized computation of traditional model, its memory occupation is decreased by 80 percent, and its serial and parallel speedups are more than 5 and 10 times respectively.