An intelligent EGWO-SCA-CS algorithm for PSS parameter tuning under system uncertainties

This paper proposes a novel hybrid technique called enhanced grey wolf optimization-sine cosine algorithm-cuckoo search (EGWO-SCA-CS) algorithm to improve the electrical power system stability. The proposed method comprises of a popular grey wolf optimization (GWO) in an enhanced and hybrid form. It embraces the well-balanced exploration and exploitation using the cuckoo search (CS) algorithm and enhanced search capability through the sine cosine algorithm (SCA) to elude the stuck to the local optima. The proposed technique is validated with the 23 benchmark functions and compared with state-of-the-art methods. The benchmark functions consist of unimodal, multimodal function from which the best suitability of the proposed technique can be identified. The robustness analysis also presented with the proposed method through boxplot, and a detailed statistical analysis is performed for a set of 30 individual runs. From the inferences gathered from the benchmark functions, the proposed technique is applied to the stability problem of a power system, which is heavily stressed with the nonlinear variation of the load and thereby operating conditions. The dynamics of power system components have been considered for the mathematical model of a multimachine system, and multiobjective function has been framed in tuning the optimal controller parameters. The effectiveness of the proposed algorithm has been assessed by considering two case studies, namely, (i) the optimal controller parameter tuning, and (ii) the coordination of oscillation damping devices in the power system stability enhancement. In the first case study, the power system stabilizer (PSS) is considered as a controller, and a self-clearing three-phase fault is considered as the system uncertainty. In contrast, static synchronous compensator (STATCOM) and PSS are considered as controllers to be coordinated, and perturbation in the system states as uncertainty in the second case study.     

A hybrid Improved Quantum-behaved Particle Swarm Optimization–Simplex method (IQPSOS) to solve power system load flow problems

This study proposes a new approach, based on a hybrid algorithm combining of Improved Quantum-behaved Particle Swarm Optimization (IQPSO) and simplex algorithms. The Quantum-behaved Particle Swarm Optimization (QPSO) algorithm is the main optimizer of algorithm, which can give a good direction to the optimal global region and Nelder Mead Simplex method (NM) which is used as a local search to fine tune the obtained solution from QPSO. The proposed improved hybrid QPSO algorithm is tested on several benchmark functions and performed better than particle swarm optimization (PSO), QPSO and weighted QPSO (WQPSO). To assess the effectiveness and feasibility of the proposed method on real problems, it is used for solving the power system load flow problems and demonstrated by different standard and ill-conditioned test systems including IEEE 14, 30 and 57 buses test systems, and compared with the conventional Newton–Raphson (NR) method, PSO and some versions of QPSO algorithms. Furthermore, the proposed hybrid algorithm is proposed for solving load flow problems with considering the reactive limits at generation buses. Simulation results prove the robustness and better convergence of IQPSOS under normal and critical conditions, when conventional load flow methods fail.     

Design of optimal PID controller using hybrid differential evolution and particle swarm optimization with an aging leader and challengers

This paper presents a new algorithm designed to find the optimal parameters of PID controller. The proposed algorithm is based on hybridizing between differential evolution (DE) and Particle Swarm Optimization with an aging leader and challengers (ALC-PSO) algorithms. The proposed algorithm (ALC-PSODE) is tested on twelve benchmark functions to confirm its performance. It is found that it can get better solution quality, higher success rate in finding the solution and yields in avoiding unstable convergence. Also, ALC-PSODE is used to tune PID controller in three tanks liquid level system which is a typical nonlinear control system. Compared to different PSO variants, genetic algorithm (GA), differential evolution (DE) and Ziegler–Nichols method; the proposed algorithm achieve the best results with least standard deviation for different swarm size. These results show that ALC-PSODE is more robust and efficient while keeping fast convergence.     

基于频繁覆盖策略的随机漂移粒子群优化算法

为了进一步提升随机漂移粒子群优化(RDPSO)算法的全局搜索能力、收敛速度以及在高维问题上的优化能力,提出一种基于频繁覆盖策略的RDPSO(FC-RDPSO)算法,并采用概率统计方法和蒙特卡罗方法分析频繁覆盖策略的可行性.在CEC''2013RPO的测试函数上将FC-RDPSO算法与多种优化算法进行对比,实验结果表明所提算法在收敛速度和全局搜索能力上表现出了突出的性能;在一组被广泛使用的大规模全局优化测试函数上的实验结果表明,FC-RDPSO算法在高维问题上同样表现出了较强的优化能力.     

Controller design for synchronization of an array of delayed neural networks using a controllable probabilistic PSO

In this paper, a controllable probabilistic particle swarm optimization (CPPSO) algorithm is introduced based on Bernoulli stochastic variables and a competitive penalized method. The CPPSO algorithm is proposed to solve optimization problems and is then applied to design the memoryless feedback controller, which is used in the synchronization of an array of delayed neural networks (DNNs). The learning strategies occur in a random way governed by Bernoulli stochastic variables. The expectations of Bernoulli stochastic variables are automatically updated by the search environment. The proposed method not only keeps the diversity of the swarm, but also maintains the rapid convergence of the CPPSO algorithm according to the competitive penalized mechanism. In addition, the convergence rate is improved because the inertia weight of each particle is automatically computed according to the feedback of fitness value. The efficiency of the proposed CPPSO algorithm is demonstrated by comparing it with some well-known PSO algorithms on benchmark test functions with and without rotations. In the end, the proposed CPPSO algorithm is used to design the controller for the synchronization of an array of continuous-time delayed neural networks.     

考虑阀点效应的电力系统经济分配算法

经济分配（ED）对于电力系统的节能至关重要,适当的分配方法可以为电厂节约巨额生产成本,然而阀点效应使得实际ED问题呈现出不光滑和非凸的特性,导致一些经典的优化算法和启发式算法无法在合理时间内发现最优解。提出一种新的改进教与学优化算法来求解计及阀点效应的经济分配问题,并采用一种新的修正策略取代罚函数法来处理约束条件。为了验证新算法的有效性和鲁棒性,选取典型的benchmark函数和ED实例进行仿真计算,结果表明与其他代表性算法相比,该方法求解精度高、收敛速度快,为计及阀点效应的经济分配问题求解提供了一条新途径。     

Price-Based Residential Demand Response Management in Smart Grids: A Reinforcement Learning-Based Approach

This paper studies price-based residential demand response management (PB-RDRM) in smart grids, in which non-dispatchable and dispatchable loads (including general loads and plug-in electric vehicles (PEVs)) are both involved. The PB-RDRM is composed of a bi-level optimization problem, in which the upper-level dynamic retail pricing problem aims to maximize the profit of a utility company (UC) by selecting optimal retail prices (RPs), while the lower-level demand response (DR) problem expects to minimize the comprehensive cost of loads by coordinating their energy consumption behavior. The challenges here are mainly two-fold: 1) the uncertainty of energy consumption and RPs; 2) the flexible PEVs’ temporally coupled constraints, which make it impossible to directly develop a model-based optimization algorithm to solve the PB-RDRM. To address these challenges, we first model the dynamic retail pricing problem as a Markovian decision process (MDP), and then employ a model-free reinforcement learning (RL) algorithm to learn the optimal dynamic RPs of UC according to the loads’ responses. Our proposed RL-based DR algorithm is benchmarked against two model-based optimization approaches (i.e., distributed dual decomposition-based (DDB) method and distributed primal-dual interior (PDI)-based method), which require exact load and electricity price models. The comparison results show that, compared with the benchmark solutions, our proposed algorithm can not only adaptively decide the RPs through on-line learning processes, but also achieve larger social welfare within an unknown electricity market environment.      

基于粒子滤波重采样与变异操作的改进粒子群算法

针对标准粒子群优化(PSO)算法在求解过程中存在求解精度低、搜索后期收敛速度慢等问题,提出一种基于粒子滤波重采样步骤与变异操作相结合的改进PSO算法——RSPSO。该算法充分利用重采样中具有较大权值的粒子被保留和复制、较小权值的粒子被舍弃的特点,并利用已有的变异操作方法克服粒子匮乏的缺点,大大增强了PSO算法中后期搜索阶段的局部搜索能力。在不同基准函数下对RSPSO算法和标准PSO算法以及文献中其他改进算法进行对比。实验结果表明, RSPSO算法的收敛速度较快,同时其搜索精度和解的稳定性均有所提高,且能够全局地解决多峰问题。     

An ICA based approach for solving profit based unit commitment problem market

With the advent of paralleling and implementation of restructuring in the power market, some routine rules and patterns of traditional market should be accomplished in a way different from the past. To this end, the unit commitment (UC) scheduling that has once been aimed at minimizing operating costs in an integrated power market, is metamorphosed to profit based unit commitment (PBUC) by adopting a new schema, in which generation companies (GENCOs) have a common tendency to maximize their own profit. In this paper, a novel optimization technique called imperialist competitive algorithm (ICA) as well as an improved version of this evolutionary algorithm are employed for solving the PBUC problem. Moreover, traditional binary approach of coding of initial solutions is replaced with an improved integer based coding method in order to reduce computational complexity and subsequently ameliorate convergence procedure of the proposed method. Then, a sub-ICA algorithm is proposed to obtain optimal generation power of thermal units. Simulation results validate effectiveness and applicability of the proposed method on two scenarios: (a) a set of unimodal and multimodal standard benchmark functions, (b) two GENCOs consist of 10 and 100 generating units.     

求解高维优化问题的扰动混沌蚁群优化算法

针对新型混沌蚁群优化算法(CAS)求解高维优化问题时存在的计算复杂和搜索精度低问题,提出了扰动混沌蚂蚁群(DCAS)算法。通过建立蚂蚁最佳位置更新贪婪规则和随机邻居选择方法有效地降低了计算复杂度;另外引入自适应扰动策略改进CAS算法,使蚂蚁增强局部搜索能力,提高了原算法的搜索精度。通过一组高维测试函数对DCAS算法的性能进行了高达1000维的仿真实验。测试结果表明,新算法对复杂的高维优化问题可行有效。     

一种引入复合形算子的变异粒子群算法

针对粒子群算法存在的收敛速度较慢和早熟收敛两大难题提出了一种新的改进型粒子群算法：搜索初期由粒子群算法进行全局寻优,当判断粒子群体已经进入局部最优区域时,引入复合形算法迅速达到局部收敛,从而有效地提高粒子群算法的局部搜索能力。同时引入自适应变异惯性权重提高摆脱局部最优的能力,增加种群的多样性。通过典型优化函数的实验验证,该算法是一种兼顾局部性能和全局搜索能力的高效算法。     

一种求解高维约束优化问题的人工蜂群算法*

针对求解高维约束优化中算法的收敛速度和解的精度不高的缺点,提出一种改进的人工蜂群约束优化算法。该算法在初始化种群和侦察蜂探寻新蜜源时采用了正交实验设计方法,并在采蜜蜂搜索时使用了改进的高斯分布估计,跟随蜂按照采蜜蜂的适应值大小选择一个采蜜蜂,在其蜜源领域内采用差异算法搜索新的蜜源;在处理约束条件时采用自适应优劣解比较方法。最后通过13个标准的Benchmark测试函数进行仿真实验,结果表明该算法在处理高维约束优化问题时具有较好的收敛性和稳定性。     

An adaptive artificial bee colony algorithm based on objective function value information

Artificial bee colony (ABC) algorithm is a novel biological-inspired optimization algorithm, which has many advantages compared with other optimization algorithm, such as less control parameters, great global optimization ability and easy to carry out. It has proven to be more effective than some evolutionary algorithms (EAs), particle swarm optimization (PSO) and differential evolution (DE) when testing on both benchmark functions and real issues. ABC, however, its solution search equation is poor at exploitation. For overcoming this insufficiency, two new solution search equations are proposed in this paper. They apply random solutions to take the place of the current solution as base vector in order to get more useful information. Exploitation is further improved on the basis of enhancing exploration by utilizing the information of the current best solution. In addition, the information of objective function value is introduced, which makes it possible to adjust the step-size adaptively. Owing to their respective characteristics, the new solution search equations are combined to construct an adaptive algorithm called MTABC. The methods our proposed balance the exploration and exploitation of ABC without forcing severe extra overhead in respect of function evaluations. The performance of the MTABC algorithm is extensively judged on a set of 20 basic functions and a set of 10 shifted or rotated functions, and is compared favorably with other improved ABCs and several state-of-the-art algorithms. The experimental results show that the proposed algorithm has a higher convergence speed and better search ability for almost all functions.     

目标空间聚类的差分头脑风暴优化算法

作为一种新型的群体智能优化算法,头脑风暴优化(brain storm optimization,BSO)算法一经提出便引起了众多研究者的关注.本文在对原始头脑风暴算法的聚类操作和变异操作改进的基础上,提出了基于目标空间聚类的差分头脑风暴(difference brain storm optimization based on clustering in objective space,DBSO–OS)算法.算法通过对目标空间的聚类替代对决策空间的聚类,减小了算法的运算复杂度;采用差分变异代替高斯变异来增加种群的多样性.多个测试函数的仿真结果表明,目标空间聚类的差分头脑风暴算法不仅提高了算法的寻优速度,而且提高了算法的寻优精度.文中进一步分析了参数对算法性能的影响,设计了最佳参数选择方案,并用于对实际热电联供经济调度问题的求解,验证了算法的实用性.     

改进的基于功率谱的趋磁性细菌算法*

为了避免超磁性细菌算法容易陷入局部极值的情况,设计全局搜索算子.进而以趋磁性细菌体内磁性颗粒产生的功率谱为基础,在模拟细菌磁矩调节过程中改进细菌磁矩调节算子和替换算子,给出结合混沌映射的功率谱替换算子,有效利用功率谱信息并增加种群多样性.实验表明,文中算法在低维问题上具有较高的收敛精度和稳定性,在高维问题上具有较好的收敛效果.     

A hybrid particle swarm optimization and its application in neural networks

In this paper, a novel particle swarm optimization model for radial basis function neural networks (RBFNN) using hybrid algorithms to solve classification problems is proposed. In the model, linearly decreased inertia weight of each particle (ALPSO) can be automatically calculated according to fitness value. The proposed ALPSO algorithm was compared with various well-known PSO algorithms on benchmark test functions with and without rotation. Besides, a modified fisher ratio class separability measure (MFRCSM) was used to select the initial hidden centers of radial basis function neural networks, and then orthogonal least square algorithm (OLSA) combined with the proposed ALPSO was employed to further optimize the structure of the RBFNN including the weights and controlling parameters. The proposed optimization model integrating MFRCSM, OLSA and ALPSO (MOA-RBFNN) is validated by testing various benchmark classification problems. The experimental results show that the proposed optimization method outperforms the conventional methods and approaches proposed in recent literature.     

具有反向学习和自适应逃逸功能的粒子群优化算法

为克服粒子群优化算法进化后期收敛速度慢、易陷入局部最优等缺点,提出一种具有反向学习和自适应逃逸功能的粒子群优化算法.通过设定的阈值,算法将种群进化状态划分为正常状态和"早熟"状态: 若算法处于正常的进化状态,采用标准粒子群优化算法的进化模式;当粒子陷入"早熟"状态,运用反向学习和自适应逃逸功能,对个体最优位置进行反向学习,产生粒子的反向解,增加粒子的反向学习能力,增强算法逃离局部最优的能力,提高算法寻优率.在固定评估次数的情况下,对8个基准测试函数进行仿真,实验结果表明:所提算法在收敛速度、寻优精度和逃离局部最优的能力上明显优于多种经典粒子群优化算法,如充分联系的粒子群优化算法(FIPS)、基于时变加速度系数的自组织分层粒子群优化算法(HPSO-TVAC)、综合学习的粒子群优化算法(CLPSO)、自适应粒子群优化算法(APSO)、双中心粒子群优化算法(DCPSO)和具有快速收敛和自适应逃逸功能的粒子群优化算法(FAPSO)等.     

基于对立策略的螺栓遗传算法

为进一步提高螺栓遗传算法的优化效率,加速寻优过程,提出基于对立策略的螺栓遗传算法。该算法在种群初始化阶段和变异阶段均用对立取代随机方式,提高产生解的质量。利用测试函数对算法的效率进行检验,将其与差分算法、遗传算法、粒子群算法和螺栓遗传算法进行对比,结果表明,新算法具有更快的收敛速度和更高的求解精度。     

Statistical analysis based reactive power optimization using improved differential evolutionary algorithm

This study presents a novel improved differential evolutionary (IDE) algorithm for optimizing reactive power management (RPM) problems. The effectiveness of IDE algorithm is tested on different unimodal and multimodal benchmark functions. The objective function of the RPM is considered as the minimization of active power losses. Initially, the power flow analysis approach is employed to detect the optimal position of flexible AC transmission system (FACTS) devices. The proposed method is used to determine the optimal value of control variables such as generator's reactive power generation, transformer tap settings, and reactive power sources. Furthermore, the efficacy of the IDE approach is compared with other promising optimization methods such as variants of differential evolution algorithm, moth flame optimization (MFO), brainstorm-based optimization algorithm (BSOA), and particle swarm optimization (PSO) on various IEEE standard test bus (i.e., IEEE-30, -57, -118, and -300) systems with active and reactive loading incorporating FACTS devices. A Static VAR compensator (SVC) for shunt compensation and a thyristor-controlled series compensator (TCSC) for series compensation were used as FACTS devices. The proposed IDE method significantly reduces the active power loss, that is, 55.65% in IEEE 30, 39.68% in IEEE 57, 16.32% in IEEE 118, and 8.56% in IEEE 300 bus system at nominal loading. Finally, the statistical analysis such as Wilcoxon signed-rank test (WSRT) and ANOVA test were thoroughly analysed to demonstrate the firmness and accuracy of the proposed technique.     

多交互式人工蜂群算法及其收敛性分析

针对人工蜂群（ABC）算法不易跳出局部最优解的缺点,提出了多交互式人工蜂群（MIABC）算法。该算法在基本人工蜂群算法的基础上引入随机邻域搜索策略,结合跨维搜索策略,且改进蜜蜂越限处理方式,使得算法搜索方式多样化,从而使得算法搜索更具跳跃性,不易陷入局部最优解,同时,对其进行收敛性分析和性能测试。在五种经典基准测试函数和时间复杂度实验上的仿真结果表明,相对于标准人工蜂群算法和基本粒子群优化（PSO）算法,该算法在1E-2精度下收敛速度提高了约30%和65%,搜索精度更优,且在高维求解问题方面有明显优势。