【作者】 言宇；

【导师】 冯林桥；

【作者基本信息】 湖南大学 ， 电力系统及其自动化， 2006， 硕士

【摘要】 随着电网经济运行问题越来越受到重视，如何在保证电压质量前提下降低网损成为电力部门急需研究和解决的重要问题。而无功优化补偿则是解决这一问题的重要手段。本文针对目前无功补偿的现状，对应用于配电网无功补偿的遗传算法进行了研究，并在现有研究成果的基础上，作了一些改进，提高了其优化能力。 首先分析和比较了各种潮流算法和无功优化算法(包括常规方法和人工智能方法)的研究现状，总结了各种方法的优缺点。 对无功补偿进行了概述，归纳了无功补偿的原则和基本方式。 针对传统潮流算法在配电网中难以收敛的缺陷，采用了适合配电网的前推回代算法，对于环网的处理，应用了叠加原理，将环网分解来计算，原理简单，计算效率高，收敛性能良好。 在保证电压品质的前提下，以无功补偿容量最小、系统的有功网损最小、综合经济效益最大为原则，建立了符合配电网实际的无功补偿数学模型。 在传统遗传算法的基础上，提出了一系列的改进策略。使用十进制编码，并保存最优个体，减少了计算时间。采用基于轮盘赌的非线性排名选择，在选择时体现了“优先规则”，克服了轮盘赌盲目性的缺点。采用自适应遗传算法，根据具体的进化情况来自适应调整交叉，变异概率，提供相对某个解的最佳的交叉、变异概率，确保了进化稳定，避免陷入局部最优。引入了混沌算子，利用混沌变量的特定内在随机性和遍历性来跳出局部最优点，有效地克服了传统遗传算法的“早熟”的缺点。最后，通过实际算例的计算，结果表明其优化效果优于传统遗传算法。更多还原

【Abstract】 With the problem of economical running of power grid being more and more attached importance to, how to reduce the grid loss on the premise that the voltage quality is guaranteed has become an important problem which the electric power department has to urgently research and resolve. The reactive power optimization compensation is an important method to resolve it. In the light of the present situation of reactive power optimization compensation, some research has been done in the Genetic Algorithms (GA) applied in reactive power optimization compensation for distribution power grid, and some reforms have been made on the base of preceding researches which have improved its optimization ability.In this thesis, all kinds of power flow algorithms and reactive power optimization algorithms (including conventional algorithms and artificial intelligence algorithms) have been analyzed and compared and their advantages and defects have been concluded.The thesis has summarized the reactive power compensation, and has concluded the principle and the basic ways of it.Aiming at the disadvantage that the conventional power flow algorithms can’t converge well in computing distribution power grid flow, I have applied the forward/backward sweep method. For the meshed distribution grid, I have used the superimposition principle to compute its flow after it is decomposed. This method is simple in principle and also has high calculating efficiency and superior convergent property.On the premise that the voltage quality is guaranteed, the mathematics model for reactive power compensation is founded on principle that the compensation power and grid loss are least and the comprehensive economic benefit is great.On the basis of Simple Genetic Algorithms (SGA), a series of improvements have been put forward. By applying decimal coding and preserving the best individual, the computing time is reduced. The nonlinear-rank select based on Roulette Wheel, which has embodied the priority-rule, has overcome the shortcoming of blindness for Roulette Wheel.The adaptable Genetic Algorithms can adjust the rates of crossover and mutation and provide the best for a specific result in the light of the specific evolution circumstances. They promote the stability and avoid to partial optimization. By introducing the Chaos Operator, it has overcome the defect of precocity for SGA, for its particularly inherent randomness and ergodicity to skip the partial optimization. At last, the results of real cases demonstrate that it is superior to standard GA.更多还原