求解机组组合问题的嵌入贪婪搜索机制的改进粒子群优化算法

提出了一种求解机组组合问题的嵌入贪婪搜索机制的改进粒子群优化算法。其特点包括:采用固定阈值处理表示机组运行状态的0、1整型变量,从而可直接应用粒子群算法求解机组组合问题,避免求解各时段中的经济负荷分配子问题;在粒子群算法迭代过程中应用变异操作更新进化速度缓慢的粒子,增强了算法的搜索能力;算法收敛后,采用基于优先列表的贪婪搜索机制做进一步寻优,既加快了算法收敛速度,又提高了解的质量。算例结果表明所提出的方法在求解机组组合问题时具有很强的搜索能力和适应性。     

基于搜索+调整的两阶段萤火虫算法求解机组组合问题

提出了一种新颖的基于搜索+调整的两阶段萤火虫算法求解机组组合问题。算法将机组组合求解流程分解为具有离散变量和连续变量的两个优化问题,通过二进制编码的萤火虫算法求解含离散变量的机组启停主问题,利用改进的实数编码萤火虫算法解决连续变量的负荷经济分配子问题,采用调整策略校核和修复约束,实现主子问题的交替迭代求解。算法通过启发式的约束调整策略,以及两种编码方式实现了离散变量和连续变量的分解优化,提高了机组组合问题求解的效率和精度。通过对6个不同规模算例的计算及与其他经典算法的对比,验证了所提算法的有效性和优越性。     

基于原-对偶内点法和混合整数规划法的机组组合问题研究

电力系统机组组合能带来显著的经济效益,随着电力市场的不断发展,在电力系统优化运行中变得尤为重要。然而电力系统机组组组合问题是一个大规模、非凸、非线性混合整数优化问题,至今仍然没有找到一种理想的优化算法。因此针对其特点,采用了原-对偶内点法和混合整数规划法相结合的算法,首先利用混合整数规划法形成伴随规划来处理离散变量,再通过内点法求解伴随规划子问题和负荷经济分配,充分发挥了两种算法在求解机组组合问题上的优势。文中对标准10机组24时段系统算例进行了仿真测试并与之前的各种优化算法进行了对比,结果表明了本文算法模型解决机组组合问题的有效性和优越性。     

用于机组组合优化的蚁群粒子群混合算法

提出了一种用于求解机组组合优化问题的蚁群粒子群混合优化算法。通过将机组组合解编码为机组操作序列,降低了蚁群算法搜索的难度,使其空间复杂度由指数型降为线性型,使采用蚁群算法求解更大规模的机组组合问题成为可能。采用协同粒子群算法求解多时段负荷的经济分配问题时,用一个粒子群处理一个时段的优化问题,通过共享粒子群间的惩罚项解决了机组爬升率的约束问题。10机和20机系统的仿真实验和分析结果验证了该方法正确性、有效性和优越性。     

求解机组组合问题的领域搜索法

机组组合问题是电力系统优化运行的一个难点,理论上难以得到其最优解。该文提出用邻域搜索(local search,LS)和内点(interior point,IP)法相结合的算法(LS-IP)解决机组组合(unit commitment,UC)非确定多项式时间(nondeterministic polynomial,NP)难问题。定义邻域的结构,并提出一种邻域的调整方法,可处理各项约束条件,保证结果的可行性。用非常小的解邻域空间代替原来庞大复杂甚至难以求解的离散空间。充分利用内点法收敛性好、精度高的优势,提高其计算速度。对100台机组24时段仿真结果表明,CPU计算时间仅为原来的4 s,所耗费用却大大降低;同时该方法收敛速度快、精度高,尤其适合于求解大规模机组的组合问题。     

基于模式搜索算法的电力系统机组组合问题

机组组合问题是一个复杂的大型混合整数非线性规划问题,目前尚未找到理想的解决方法。本文提出一种用于混合变量的模式搜索方法(GPSMV)解决机组组合问题。该方法能求解非凸、非线性、不可微甚至不连续的规划问题,理论上能保证全局收敛于稳定的解,其仅需要求目标函数及由约束条件构成的障碍函数值而不需要对目标函数和约束条件求导。在优化过程中离散变量作为独立的变量,而不是把原问题分成离散和连续两层来处理,适合于求解离散和连续的混合变量问题。最后对10～100机,26机24时段等六个系统进行仿真试验验证该算法。     

基于粗糙集理论与CLSDE算法的环境经济调度优化模型

针对环境经济发电调度优化问题,提出了一种应用粗糙集理论构建评价函数的多目标优化方法,并提出了基于混沌局部搜索策略的差分进化算法(chaotic local search strategy differential evolution algorithm,CLSDE)的求解算法。应用粗糙集理论确定经济调度和环境调度函数的约束度,以确定各目标函数在优化模型中的权值。采用CLSDE算法求解环境经济调度(environmental economic dispatch,EED)多目标优化模型,该算法只对目标函数中的变量进行编码,约束条件函数中的变量随机产生,每代进化完毕后,对最优个体进行混沌局部搜索,克服了差分进化算法局部搜索能力较弱和惩罚函数方法中惩罚参数选择较难的问题。对IEEE30节点的标准测试系统进行了仿真计算,结果表明CLSDE算法在解决环境经济调度问题时具有可行性和有效性,在不增加污染气体排放量的同时降低燃料费用,使环境经济调度更能兼顾发电调度的经济利益与环境利益。     

机组组合算法中起作用整数变量的辨识方法

应用成熟的数学规划方法求解机组组合问题是当前的发展趋势,但是整数变量太多使得该问题的求解效率太低。在深入研究机组组合的模型特点以及电力系统的物理本质的基础上,提出了混合整数规划问题中起作用整数变量的新概念,据此提出了能够综合考虑系统时段耦合约束、网络安全约束以及机组启停费用的规范化起作用整数变量辨识方法。通过对起作用整数变量进行组合优化计算,将不起作用整数变量直接转化为连续变量求解,有效缩小了机组组合的寻优空间,在不影响机组组合最优解的前提下,提高了求解效率,对大幅度提高机组组合的计算效率和应用水平具有重要的价值。理论分析和算例测试验证了该方法的有效性。     

机组耗量特性的混合整数模型建立与分析

对机组耗量特性的建模是机组组合问题的一个重要组成部分.文中建立并分析了机组耗量特性的5种模型,并在IEEE RTS 96系统上,分别针对具有凸连续、非凸连续和非连续耗量特性曲线的机组,通过优化其在某日24时段的出力,比较各模型的求解效率,并根据各模型所引入变量数目对测试结果进行分析,从而为根据机组特性选择合适的模型以提高求解效率提供参考.结果表明:影响算法求解性能的主要因素是模型中整数变量的数目.对于凸连续耗量特性机组,尽量采用各区间出力叠加的建模方法,以避免引入整数变量;对于非凸和非连续耗量特性机组,引入辅助整数变量不可避免,此时则应采用连续变量较少的模型.     

应用于机组组合问题的启发式蚁群算法

针对机组组合(UC)的整数一实数混合规划问题,先用二次规划计算各时段不同机组组合最优负荷分配,并选取各时段煤耗最小组合构造启发式初始解,根据解提供的信息设计一种删除不合理候选运行组合的方法,大幅缩小解空间.利用最大最小蚁群算法(MMAS)在解空间中搜索机组启停策略.针对MMAS效率低搜索慢的问题,算法在迭代完成后引入局部搜索.为降低启动煤耗,在蚂蚁转移概率公式以及信息素更新表达式中加入运行机组数因子及启动煤耗惩罚项,降低启动煤耗高的组合被选中概率,进而优化各时段同时运行机组数量.仿真结果表明以上改进能够大幅提高算法求解速度,具有较强的全局寻优能力.     

HSA based solution to the UC problem

Unit-commitment (UC) as a complicated problem needs powerful methods to solve. This paper presents the use of harmony search algorithm (HSA), a recently developed meta-heuristic algorithm, in order to obtain optimal solution for the UC problem. The proposed algorithm has simple implementation and provides optimal solutions in a reasonable time. The method is tested using small and large scale test cases in the literature. Numerical results show that the proposed algorithm can find better solutions in comparison with conventional methods and it is an efficient way to solve UC problems especially in large-scale power systems.     

Using immune genetic algorithm based hybrid techniques for short-term unit commitment problem

This paper presents a hybrid chaos search (CS), immune algorithm (IA)/genetic algorithm (GA), and fuzzy system (FS) method (CIGAFS) for solving short-term thermal generating unit commitment (UC) problems. The UC problem involves determining the start-up and shut-down schedules for generating units to meet the forecasted demand at the minimum cost. The commitment schedule must satisfy other constraints such as the generating limits per unit, reserve, and individual units. First, we combined the IA and GA, then we added the CS and the FS approach. This hybrid system was then used to solve the UC problems. Numerical simulations were carried out using three cases: 10, 20, and 30 thermal unit power systems over a 24 h period. The produced schedule was compared with several other methods, such as dynamic programming (DP), Lagrangian relaxation (LR), standard genetic algorithm (SGA), traditional simulated annealing (TSA), and traditional Tabu search (TTS). A comparison with an immune genetic algorithm (IGA) combined with the CS and FS was carried out. The results show that the CS and FS all make substantial contributions to the IGA. The result demonstrated the accuracy of the proposed CIGAFS approach.     

基于矩阵实数编码遗传算法求解大规模机组组合问题

该文提出了一种采用矩阵实数编码遗传算法(MRCGA)进行机组组合优化的新方法：采用矩阵实数编码方式对整体发电计划进行编码后，可直接运用遗传操作求解机组组合问题，避免将其分解成机组启停安排和经济负荷分配的两层优化问题进行求解；采用多窗口变异技术，增强了算法的搜索能力。此方法提出了一种新的个体调整方法，可以处理各项约束条件，保证了结果的可行性。文中通过2个算例及与其它算法的对比分析，验证了所提出的方法在大规模机组组合问题求解时具有很强的适应性和全局搜索能力。     

Application of pattern search method to power system valve-point economic load dispatch

Direct search (DS) methods are evolutionary algorithms used to solve constrained optimization problems. DS methods do not require any information about the gradient of the objective function at hand, while searching for an optimum solution. One of such methods is pattern search (PS) algorithm. This study presents a new approach based on a constrained pattern search algorithm to solve well-known power system economic load dispatch problem (ELD) with valve-point effect. For illustrative purposes, the proposed PS technique has been applied to various test systems to validate its effectiveness. Furthermore, convergence characteristics and robustness of the proposed method has been assessed and investigated through comparison with results reported in literature. The outcome is very encouraging and proves that pattern search (PS) is very applicable for solving power system economic load dispatch problem.     

基于PSO-GA算法的电力系统机组组合研究

机组组合优化问题是一个大规模、多约束、非线性的混合整数规划问题,因此求解非常困难。粒子群优化(PSO)算法是一类随机全局优化技术,它通过粒子间的相互作用发现复杂搜索空间中的最优区域。PSO算法的优势在于操作简单,可调参数少易于实现而又功能强大。该文采用二进制粒子群优化方法解决机组状态组合问题,用遗传算法结合启发式技术解决经济分配问题,并对最小开停机时间及启停费用进行了处理,使得运算速度大大加快。方法的可行性在10台机组系统中检验。模拟结果表明文章所提出的算法具有收敛速度快及解的质量高等优点。     

Application embedded chaos search immune genetic algorithm for short-term unit commitment

This paper presents a Hybrid Chaos Search (CS) immune algorithm (IA)/genetic algorithm (GA) and Fuzzy System (FS) method (CIGAFS) for solving short-term thermal generating unit commitment (UC) problems. The UC problem involves determining the start-up and shutdown schedules for generating units to meet the forecasted demand at the minimum cost. The commitment schedule must satisfy other constraints such as the generating limits per unit, reserve and individual units. First, we combined the IA and GA, then we added the chaos search and the fuzzy system approach. This hybrid system was then used to solve the UC problems. Numerical simulations were carried out using three cases: 10, 20 and 30 thermal unit power systems over a 24 h period. The produced schedule was compared with several other methods, such as dynamic programming (DP), Lagrangian relaxation (LR), Standard genetic algorithm (SGA), traditional simulated annealing (TSA), and Traditional Tabu Search (TTS). A comparison with an IGA combined with the Chaos Search and FS was carried out. The results show that the Chaos Search and FS all make substantial contributions to the IGA. The result demonstrated the accuracy of the proposed CIGAFS approach.     

基于外逼近方法的中期机组组合问题

利用外逼近方法（OAM）提出一种求解机组组合（UC）问题新的确定性方法。OAM是一种分解方法,它把UC问题分解为一系列的混合整数线性规划（MILP）主问题和非线性规划（NLP）子问题。应用分支割平面方法求解MILP,应用新的零空间内点法求解NLP。54机组168时段等多个系统的数值仿真表明,OAM具有快速的收敛速度,能有效处理爬坡约束,为大规模安全约束机组组合问题的有效求解提供了一条新途径。     

一类全局收敛的线搜索滤子算法

提出一类求解非线性规划问题的新的线搜索滤子方法。Lagrangian函数的梯度范数被引用到新方法的不可行测度中,可以加快收敛速度。在较温和的假设下,算法能搜索到的极限点中至少有一个为稳定点。最后,列出一些数值的计算结果。     

Short-term thermal generation scheduling using improved immune algorithm

This paper proposes a new immune algorithm (NIA), which merges the fuzzy system (FS), the annealing immune (AI) method and the immune algorithm (IA) together, to resolve short-term thermal generation unit commitment (UC) problems. This proposed method differs from its counterparts in three main aspects, namely: (1) changing the crossover and mutation ratios from a fixed value to a variable value determined by the fuzzy system method, (2) using the memory cell and (3) adding the annealing immune operator. With these modifications, we can attain three major advantages with the NIA, i.e. (1) the NIA will not fall into a local optimal solution trap; (2) the NIA can quickly and correctly find a full set of global optimal solutions and (3) the NIA can achieve the most economic solution for unit commitment with ease. The UC determines the start-up and shut-down schedules for related generation units to meet the forecasted demand at a minimum cost while satisfying other constraints, such as each unit's generating limit. The NIA is applied to six cases with various numbers of thermal generation units over a 24-h period. The schedule generated by the NIA is compared with that by several other methods, including the dynamic programming (DP), the Lagrangian relaxation (LR), the standard genetic algorithm (GA), the traditional simulated annealing (SA) and the traditional Tabu search (TS). The comparisons verify the validity and superiority in accuracy for the proposed method.