An adaptive chaotic artificial bee colony algorithm for short-term hydrothermal generation scheduling

Short-term hydrothermal scheduling (SHS) is a complicated nonlinear optimization problem with a set of constraints, which plays an important role in power system operations. In this paper, we propose to use an adaptive chaotic artificial bee colony (ACABC) algorithm to solve the SHS problem. In the proposed method, chaotic search is applied to help the artificial bee colony (ABC) algorithm to escape from a local optimum effectively. Furthermore, an adaptive coordinating mechanism of modification rate in employed bee phase is introduced to increase the ability of the algorithm to avoid premature convergence. Moreover, a new constraint handling method is combined with the ABC algorithm in order to solve the equality coupling constraints. We used a hydrothermal test system to demonstrate the effectiveness of the proposed method. The numerical results obtained by ACABC are compared with those obtained by the adaptive ABC algorithm (AABC), the chaotic ABC algorithm (CABC) and other methods mentioned in literature. The simulation results indicate that the proposed method outperforms those established optimization algorithms.     

基于改进飞蛾扑火算法的单时刻参数可变机组组合优化

机组组合属于高维、离散、非凸的混合整数非线性规划问题,具有NPhard特点。提出结合二进制粒子群算法与混沌飞蛾扑火算法的单时刻参数可变机组组合优化方法,将总时刻机组组合问题依次、逐一分解为单时刻启停状态主问题与单时刻经济分配子问题,对主、子问题分别运用二进制粒子群算法与改进飞蛾扑火算法进行交替迭代求解以提升求解速率。运用参数可变策略与优先次序法概率调整策略对算法参数及候选解进行修正,以提升算法运行效率及候选解质量。测试结果表明,本文所提方法具有良好的运算速率及收敛精度,能有效求解大规模机组组合问题。     

机组负荷分配的多目标优化和多属性决策

同时计及机组运行的经济性和污染排放,将基于进化算法的多目标优化技术与多属性决策方法联合运用,针对火电厂负荷优化分配问题进行了研究。对于多目标优化问题,采用改进的非支配解排序的多目标遗传算法(NSGAⅡ),求出Pareto最优解,由这些Pareto最优解构成决策矩阵,使用客观赋权的信息熵方法对最优解的属性进行权值计算,然后用逼近理想解的排序方法(TOPSIS)进行多属性决策(MADM)研究,对Pa-reto最优解给出排序。给出了3台机组负荷分配的优化算例,计算表明所提方法适应性好,结果合理可行。     

基于协作智能与子梯度优化算法的电力业务差异化QoS路由策略*

针对不同电力业务提供端到端的、确定性的带宽、时延、丢包率、时延抖动等网络QoS,是未来泛在电力物联网通信网络支撑的关键任务之一。文中提出一种基于协作智能与子梯度优化算法的差异化QoS路由策略,解决电力业务多约束条件下路由选择收敛速度慢、易陷入次优解、解的可行性检验缺失、最优性难以证明等问题。具体而言,利用子梯度方法能够动态调整QoS多约束条件惩罚因子,从而在迭代过程中执行可行性检验,并在获得最终解时评估其最优性;利用基本蚁群算法改进后的协作机制,提高不同质量路径的区分度,达到快速收敛、避免进入局部次优解的目的。实验结果表明文中提出的算法较已有方法能够更快地收敛至最优值,且提供了验证解的可行性与最优性手段。     

求解机组组合问题的改进离散粒子群算法

电力系统机组组合问题是一个高维数、离散、非线性的大规模复杂工程优化问题.文中提出了一种基于改进离散粒子群优化算法求解机组组合问题的新方法.首先采用新的策略生成粒子,以保证所有生成的粒子均为满足基本约束条件的可行解,使整个算法只在可行解区域进行优化搜索;然后引入优化窗口的概念和启发式的规则以缩短计算时间和提高优化精度.仿真结果表明所提出的算法具有解的质量高、收敛速度快的特点,充分证明了它能很好地解决机组组合问题.     

Short-term hydrothermal scheduling using clonal selection algorithm

An efficient optimization procedure based on the clonal selection algorithm (CSA) is proposed for the solution of short-term hydrothermal scheduling problem. CSA, a new algorithm from the family of evolutionary computation, is simple, fast and a robust optimization tool for real complex hydrothermal scheduling problems. Hydrothermal scheduling involves the optimization of non-linear objective function with set of operational and physical constraints. The cascading nature of hydro-plants, water transport delay and scheduling time linkage, power balance constraints, variable hourly water discharge limits, reservoir storage limits, operation limits of thermal and hydro units, hydraulic continuity constraint and initial and final reservoir storage limits are fully taken into account. The results of the proposed approach are compared with those of gradient search (GS), simulated annealing (SA), evolutionary programming (EP), dynamic programming (DP), non-linear programming (NLP), genetic algorithm (GA), improved fast EP (IFEP), differential evolution (DE) and improved particle swarm optimization (IPSO) approaches. From the numerical results, it is found that the CSA-based approach is able to provide better solution at lesser computational effort.     

Multi-objective optimization of hydrothermal energy system considering economic and environmental aspects

Along with continuous global warming, the environmental problems, besides the economic objective, are expected to play more and more important role in the operation of hydrothermal power system. In this paper, the short-term multi-objective economic environmental hydrothermal scheduling (MEEHS) model is developed to analyze the operating approach of MEEHS problem, which simultaneously optimize energy cost as well as the pollutant emission effects. Meanwhile, transmission line losses among generation units, valve-point loading effects of thermal units and water transport delay between hydraulic connected reservoirs are taken into consideration in the problem formulation. In order to solve MEEHS problem, a new multi-objective cultural algorithm based on particle swarm optimization (MOCA-PSO) is presented in way of combining the cultural algorithm framework with particle swarm optimization (PSO) to carry though the evolution of population space. Furthermore, an effective constrain handling method is proposed to handle the operational constraints of MEEHS problem. The proposed method is applied to a hydrothermal power system consisting of four hydro plants and three thermal units for the case studies. Compared with several previous methods, the simulation solutions of MOCA-PSO with smaller fuel cost and lower emission effects proves that it can be an alternative method to deal with MEEHS problems. The obtained results demonstrate that the change of optimization objective leads to the shift of optimal operation schedules. Finally, the scheduling results of MEEHS problem offer enough choices to the decision makers. Thus, the operation with better performance of environment is achieved by more energy system cost.     

含分布式电源的配电网故障紧急恢复与抢修协调优化策略

随着分布式电源的规模化接入,传统配电网故障恢复策略逐渐难以适应实际需要.为此,提出一种含分布式电源的配电网故障紧急恢复与抢修协调优化策略.首先,在故障紧急恢复模型中引入典型负荷时变性需求模型,优先恢复需求度高的负荷.以抢修时间最短和社会经济损失最小为综合目标函数得到故障抢修模型.然后,研究故障紧急恢复与抢修协调优化策略,利用主网与孤岛协调控制进行故障恢复,通过改进粒子群算法得到最优抢修顺序.在抢修过程中,考虑负荷及时变性需求变化,调整故障紧急恢复与抢修最优方案,保证配电网可靠、快速恢复正常运行状态.最后,通过算例仿真验证了所提策略的有效性.     

基于分布式协同粒子群优化算法的电力系统无功优化

该文提出一种新颖的用于求解无功优化问题的分布式协同粒子群优化算法.考虑到大规模电力系统集中优化难度较大,采用分层控制中的分解-协调思想将大系统分解成若干个独立的子系统,有效地降低求解问题的复杂度,并采用混合策略在各子系统问进行协同进化.此外,子系统的无功优化采用了一种改进的粒子群优化算法,考虑了更多粒子的信息,能有效地提高算法的收敛精度和计算效率.对4个不同大小规模的系统进行的仿真计算结果表明该文提出的方法能够获得高质量的解,并且计算时间短,效率高,适合求解大规模电力系统的无功优化问题.     

An -dominance-based multiobjective genetic algorithm for economic emission load dispatch optimization problem

In this paper, a novel multiobjective genetic algorithm approach for economic emission load dispatch (EELD) optimization problem is presented. The EELD problem is formulated as a non-linear constrained multiobjective optimization problem with both equality and inequality constraints. A new optimization algorithm which is based on concept of co-evolution and repair algorithm for handling non-linear constraints is presented. The algorithm maintains a finite-sized archive of non-dominated solutions which gets iteratively updated in the presence of new solutions based on the concept of -dominance. The use of -dominance also makes the algorithms practical by allowing a decision maker to control the resolution of the Pareto-set approximation by choosing an appropriate value.The proposed approach is carried out on the standard IEEE 30-bus 6-genrator test system. The results demonstrate the capabilities of the proposed approach to generate true and well-distributed Pareto-optimal non-dominated solutions of the multiobjective EELD problem in one single run. Simulation results with the proposed approach have been compared to those reported in the literature. The comparison demonstrates the superiority of the proposed approach and confirms its potential to solve the multiobjective EELD problem.     

An improved PSO technique for short-term optimal hydrothermal scheduling

This paper presents a new approach to the solution of optimal power generation to short-term hydrothermal scheduling problem, using improved particle swarm optimization (IPSO) technique. The practical hydrothermal system is highly complex and possesses nonlinear relationship of the problem variables, cascading nature of hydraulic network, water transport delay and scheduling time linkage that make the problem of finding global optimum difficult using standard optimization methods. In this paper an improved PSO technique is suggested that deals with an inequality constraint treatment mechanism called as dynamic search-space squeezing strategy to accelerate the optimization process and simultaneously, the inherent basics of conventional PSO algorithm is preserved. To show its efficiency and robustness, the proposed IPSO is applied on a multi-reservoir cascaded hydro-electric system having prohibited operating zones and a thermal unit with valve point loading. Numerical results are compared with those obtained by dynamic programming (DP), nonlinear programming (NLP), evolutionary programming (EP) and differential evolution (DE) approaches. The simulation results reveal that the proposed IPSO appears to be the best in terms of convergence speed, solution time and minimum cost when compared with established methods like EP and DE.     

电力系统经济负荷分配的人工免疫混沌优化算法

提出了一种用于求解复杂电力系统经济负荷分配问题的新的人工免疫混沌优化算法，该算法融合了人工免疫算法极强的全局搜索能力以及混沌优化方法适合局部搜索的特点。在优化过程中，人工免疫算法通过克隆选择、克隆扩增和高频变异形成记忆细胞，并将其作为最优解的近似解，然后按混沌运动规律在近似解的邻域内进行局部搜索，进而获得精确的最优解。多个算例仿真结果表明，所提出的算法能够有效地解决经济负荷分配问题。     

Teaching learning based optimization for short-term hydrothermal scheduling problem considering valve point effect and prohibited discharge constraint

This article presents a novel teaching learning based optimization (TLBO) to solve short-term hydrothermal scheduling (HTS) problem considering nonlinearities like valve point loading effects of the thermal unit and prohibited discharge zone of water reservoir of the hydro plants. TLBO is a recently developed evolutionary algorithm based on two basic concept of education namely teaching phase and learning phase. In first phase, learners improve their knowledge or ability through the teaching methodology of teacher and in second part learners increase their knowledge by interactions among themselves. The algorithm does not require any algorithm-specific parameters which makes the algorithm robust. Numerical results for two sample test systems are presented to demonstrate the capabilities of the proposed TLBO approach to generate optimal solutions of HTS problem. To test the effectiveness, three different cases namely, quadratic cost without prohibited discharge zones; quadratic cost with prohibited discharge zones and valve point loading with prohibited discharge zones are considered. The comparison with other well established techniques demonstrates the superiority of the proposed algorithm.     

一种基于混沌序列的动态差分进化算法在电力系统动态经济调度中的应用

针对电力系统动态经济调度(DED)问题,引入差分进化算法,提出一种基于混沌序列的动态差分进化算法(ＡＤＤＥＣＳ)。该算法采用混沌序列动态调整差分进化算法的参数设置,保持种群的多样性。动态搜索策略被用于提高算法的整体搜索性能,它由全局搜索策略和局部搜索策略2部分组成。为了加速收敛和解决DED复杂的约束处理问题,采用基于多目标概念的约束处理机制,并提出一种根据机组调节能力来按比例分摊不可行解约束违反量的新方法。同时在搜索过程中,通过采用不同的变异策略结合改进的随机搜索策略来避免算法早熟,增强全局最优解的搜索能力。提出的方法的可行性和有效性由10机测试系统来证明,和其他方法相比,ADDECS方法计算速度快,计算精度高且鲁棒性强。     

考虑多种因素评估的微电网优化调度

基于微网调度中不同利益主体追求的目标不同,从经济、技术、环境评估三方面分别进行考虑,提出相应的最优调度策略。建立关于发电和交易成本最低的经济指标模型、网损最小的技术指标模型及污染气体治理费用最低的环境指标模型,并针对各目标之间存在的冲突,提出一种最优组合策略。结合遗传算法与层次分析法,对多目标调度策略进行优化:通过自适应遗传算法得到多目标优化调度的Pareto最优解集;通过层次分析法对解集进行评估,为决策者选择最优的调度方案。最后以一欧洲典型微网为算例,通过仿真验证了该模型的有效性和可行性。     

基于量子微分进化算法的分布式电源多目标优化规划

为了克服再生能源的间歇性、随机性导致的分布式电源优化结果不够准确,提出了一种基于概率特性的电源-负荷综合模型,将分布式电源的随机出力问题转化成确定性问题。考虑分布式电源对配网的影响,建立了包含建设运行费用、网络损耗、可靠性费用和环境因素的多目标优化模型。提出采用量子微分进化算法对分布式电源接入配网进行优化配置,该算法采用量子的概率表达特性和叠加态特性,潜在地提高了算法的寻优效率,同时采用变异和交叉操作,保持了良好的种群多样性。通过对算例的分析,表明所提出的模型和算法合理、可行。     

Multiobjective thermal power dispatch using opposition-based greedy heuristic search

This paper proposes an opposition-based greedy heuristic search (OGHS) strategy to solve multi-objective thermal power dispatch problem as a non-linear constrained optimization problem considering operating cost and pollutant emissions as competing objectives. The optimization problem is solved to find global solution, in case any one objective function is non-convex and non-differentiable. To generate initial population opposition-based learning is applied to select good candidates by exploring the search space extensively. Further, opposition-based learning is exploited for migration to maintain the diversity in the set of feasible solutions. Proposed method applies mutation strategy by perturbing the genes heuristically and seeking better one. This concept introduces parallelism and makes the algorithm always greedy for better solution. The greediness and randomness pulls the algorithm towards the global solution. The algorithm is also self sufficient without the need of tuning any parameter that effects acceleration of the algorithm. Fuzzy-theory is employed for decision-making that selects best solution from available non-inferior solutions. Feasible solution is also achieved heuristically that modifies the generation-schedule and avoids violation of operating generation limits. Proposed method has been implemented to analyze economic and multi-objective thermal power dispatch problems considering ramp-rate limits, prohibited-operating-zones, valve-point-loading effects, multiple-fuel options, environmental effects, and exact transmission losses encountered in realistic power system operation. The validity of proposed method is demonstrated on medium and large power systems. Proposed optimization technique is emerged out to compete with existing solution techniques. Wilcoxon signed-rank test for independent samples also proves the supremacy of proposed algorithm OGHS.     

Short term hydrothermal scheduling using multi-objective differential evolution with three chaotic sequences

Short-term hydrothermal optimal scheduling with economic emission (SHOSEE) is a multi-objective and complex constrained optimization problem. In this paper, three chaotic sequences based multi-objective differential evolution (CS-MODE) is proposed to solve this SHOSEE problem, and it utilizes elitist archive mechanism to retain the non-dominated individuals, which improves the convergence ability in the differential evolution, and a heuristic two-step constraint-handling technique is utilized to handle those complex equality and inequality constraints in SHOSEE problem. Furthermore, in order to avoid premature convergence, the proposed CS-MODEs have integrated three chaotic mappings into differential evolution to implement population space search, it enlarges search space and enriches the diversity of individuals generated in evolution process. The compromise scheme is selected from the non-dominated set to represent the average efficiency level on the hydrothermal system, and the obtained simulation result also reveals the feasibility and effectiveness of proposed CS-MODEs in comparison to other methods established recently.     

基于混合DE-PSO多目标算法的动态环境经济调度

电力系统中的动态环境经济调度(DEED)是一个多变量、强约束、非凸的多目标优化问题,传统方法很难进行求解。基于微分进化(DE)算法的快速收敛性和粒子群优化(PSO)算法的搜索多样性,提出一种融合2种算法优点的混合DE-PSO多目标优化算法来求解DEED问题,该算法基于外部存档集和Pareto占优原则,采用自适应参数的DE和PSO双种群更新策略以及一种改进的Pareto解集裁剪方法。引入3种指标评价算法的性能,并采用模糊决策技术从Pareto前沿中提取折中解以供决策者进行选择。经典算例的仿真结果表明所提方法能同时优化成本和排放这2个冲突的目标,且获得了比其他算法更为宽广和均匀的Pareto前沿,体现了所提方法的可行性和优越性。     

A genetic algorithm solution approach to the hydrothermal coordination problem

In this paper, a genetic algorithm solution to the hydrothermal coordination problem is presented. The generation scheduling of the hydro production system is formulated as a mixed-integer, nonlinear optimization problem and solved with an enhanced genetic algorithm featuring a set of problem-specific genetic operators. The thermal subproblem is solved by means of a priority list method, incorporating the majority of thermal unit constraints. The results of the application of the proposed solution approach to the operation scheduling of the Greek Power System, comprising 13 hydroplants and 28 thermal units, demonstrate the effectiveness of the proposed algorithm.