Optimal Location of Thyristor-Controlled Series Compensation and Static VAR Compensator to Enhance Steady-state Performance of Power System with Wind Penetration

Wind generation connection to power system affects steady-state and transient stability. Furthermore, this effect increases with the increase of wind penetration in generation capacity. In this article, optimal location of flexible AC transmission system devices is carried out to solve the steady-state problems of wind penetration using a genetic algorithm. Case study is carried out on modified IEEE 39-bus system with wind penetration increases by 50%; the system suffers from outage of one generator with load decrease in one of system buses by 15%. The system suffers from minimum voltage reduction, total loss increase, and violation of power and power angle limits. Series and shunt flexible AC transmission system devices are used in this article. Results showed that series flexible AC transmission system devices in certain range are able to solve these problems associated with wind penetration in power systems with acceptable cost saving.     

Distributed generation placement for congestion management considering economic and financial issues

Congestion management is one of the most important functions of independent system operator (ISO) in the restructured power system. This paper presents two new methodologies for optimal sitting and sizing of distributed generations (DGs) in the restructured power systems for congestion management. The proposed methodologies are based upon locational marginal price (LMP) and congestion rent that forms a priority list of candidate buses to reduce the solution space. The proposed priority list facilitates the optimal placement as well as the level of output power of DGs. The proposed methods are implemented on the IEEE 14-bus and IEEE 57-bus test systems to illustrate their effectiveness. An economic consideration of DG placement and its operation is also studied. Simulation studies and results analysis show that the proposed methodologies are capable of finding the best location and optimal size for DGs, which can alleviate congestion in transmission systems.     

计及需求响应的含风电场电力系统发电与碳排放权联合优化调度

提出了一种节能减排形势下的优化调度模型和解法。研究对象上,文中研究了风电、火电、需求响应3种发电(虚拟发电)形式,需求响应可为系统提供零碳发电资源和旋转备用。模型建立上,基于多目标安全约束机组组合模型,采用发电和碳排放联合调度的方式,寻求经济目标与排放目标的折中协调解;约束条件综合考虑了需求响应、安全约束和碳排放等多种约束。解法上,采用分段线性化的方式,利用混合整数线性规划进行求解,解法适用于大规模系统,使模型更具实用价值。算例分析表明,决策结果能够兼顾排放与成本,并且在调度中引入需求响应可提高系统的风电消纳能力,具有显著的节能减排效益。     

Distributed generation planning using differential evolution accounting voltage stability consideration

This paper describes a technique for selection of buses in a sub transmission system for location of distributed generation (DG) and determination of their optimum capacities by minimizing transmission losses. The buses have been selected based on incremental voltage (dV/dP) sensitivities. Line flow constraints have been accounted. Type-3 DG i.e. wind turbine along with induction generator has been considered for the study. Differential evolution (DE) has been used to evaluate the optimum DG capacity and results have been compared with those obtained using bare bones particle swarm optimization (BBPSO) and multi-membered non-recombinative (μ + λ) evolution strategy (MMNRES). The developed algorithms have been implemented on standard 6-bus and 30-bus test systems.     

基于免疫遗传算法的智能配电网分布式电源选址定容

合理地对分布式电源进行选址和定容对于智能配电网规划非常重要。文章在研究分布式电源规划的基础上,建立了以有功网损最小为目标函数的优化模型,用罚函数法将分布式电源规划问题转化为无约束问题,针对该模型特点,首次将免疫遗传算法应用到分布式电源选址和定容问题的求解中。该算法综合了免疫系统和遗传算法的优点,具有良好的全局收敛能力。对33节点配电测试系统进行仿真计算,将仿真结果与标准遗传算法进行比较。验证了免疫遗传算法具有一定的收敛性和适应性。     

Optimal DG Allocation in Radial Distribution Systems with High Penetration of Non-linear Loads

This paper addresses the optimal distributed generation sizing and siting for voltage profile improvement, power losses, and total harmonic distortion (THD) reduction in a distribution network with high penetration of non-linear loads. The proposed planning methodology takes into consideration the load profile, the frequency spectrum of non-linear loads, and the technical constraints such as voltage limits at different buses (slack and load buses) of the system, feeder capacity, THD limits, and maximum penetration limit of DG units. The optimization process is based on the Genetic Algorithm (GA) method with three scenarios of objective function: system power losses, THD, and multi-objective function-based power losses and THD. This method is executed on the IEEE 31-bus system under sinusoidal and non-sinusoidal (harmonics) operating conditions including load variations within the 24-hr period. The simulation results using Matlab environment show the robustness of this method in optimal sizing and siting of DG, efficiency for improvement of voltage profile, reduction of power losses, and THD. A comparison with particle swarm optimization (PSO) method shows that the proposed method is better than PSO in reducing the power losses and THD in all suggested scenarios.     

考虑环境因素的分布式发电多目标优化配置

分布式发电优化布置与定容问题是智能电网发展中所面对的一个重要课题。该文在节点有功、无功网损微增率基础上,通过负荷功率法将两者结合,提出等效网损微增率的概念。通过计算该微增率并对其进行排序,可确定分布式发电(distributed generation,DG)的最优安装位置,并且最小化输电线路网损。对于DG定容问题,该文同时考虑了有功网损、电压改善程度和环境改善程度这3个重要指标,将DG优化容量确定问题转化为一个多目标非线性规划问题。采用目标逼近和二次序列规划方法对提出的算法进行求解。算例结果表明,采用该方法确定DG在系统中的布置位置和容量可有效提高系统运行电压,降低有功网损,减少电厂排放的污染气体。该方法对DG在规划阶段的选址和定容问题有着一定的实用价值。     

考虑运行策略和投资主体利益的电转气容量双层优化配置

电转气(P2G)技术的日益成熟,促进了电网和天然气网间的耦合,使两者间实现大规模互联成为可能。文中利用条件风险价值(CVaR)理论,对风电不确定性给电—气互联系统带来的运行风险及其成本进行了分析。在计及风力发电企业和电—气互联系统两个利益主体后,构建了P2G设备容量配置双层规划模型,以风力发电企业净利润作为上层目标,电—气互联系统运行成本为下层目标。并通过基于灾变遗传算法和内点法的混合求解算法进行仿真求解。利用IEEE 39节点电网和修改的比利时20节点天然气网组成的仿真系统,验证了配置P2G设备来提高风电消纳率和降低系统弃风风险的可行性。并进一步对比分析了置信度和弃风风险成本系数对P2G配置策略及系统运行的影响。     

Optimal Installation of Different DG Types in Radial Distribution System Considering Load Growth

In power distribution network, the gradual increase in system load is a natural process, and it results in increased real and reactive power losses and reduced voltage profile. In this paper, optimal single and multiple installations of different types of distributed generation (DG) units are used to handle annual growth in system load, while satisfying system operational constraints. For load growth study, a predetermined growth in system annual load is considered. Minimization of system total real power loss is taken as the main objective, and optimal location and sizing of different DG types are determined using a hybrid configuration of weight-improved particle swarm optimization (WIPSO) with gravitational search algorithm (GSA) called hybrid WIPSO-GSA algorithm. The effect of load growth is studied using standard 33-bus radial distribution system, and the results illustrate significant reduction in system real and reactive power losses, enhancement in system voltage profile, and improvement in load carrying capacity of distribution feeder sections. Moreover, the economic benefits of DG on system annual load growth are also established. Also, the effectiveness of the proposed algorithm is demonstrated by comparing the results with other evolutionary optimization techniques.     

机会约束随机动态经济调度的凸松弛迭代求解法

大规模风电并网给电力系统运行带来了重大技术挑战,其出力的随机性和波动性增加了线路传输能力和备用调节能力不足的风险,传统的确定性经济调度方法已不完全适用。首先提出了一种基于混合高斯分布的机会约束随机动态经济调度模型,该模型将最小备用约束和线路传输容量约束建模为机会约束,并引入调频机组的仿射控制策略以实时平衡风功率的波动。然后提出了一种机会约束规划的松弛迭代求解方法,将随机调度模型转化为二次规划模型以实现快速有效求解。利用中国西南某省25个风电场的现场数据以及IEEE 118节点系统进行算例分析,验证了混合高斯分布对风电预测误差的拟合精度,以及所提方法的可行性。     

计及风电置信风险的源网协调多目标优化调度

为了更为合理灵活地评估风电高估/低估给电力系统优化调度带来的风险性以及降低调度决策的保守性,基于风电机会约束提出风电高估/低估置信风险功率偏差量化计算方法,并在决策变量中引入变压器变比调节和无功补偿容量优化,构建计及风电置信风险和源网协调运行的经济/风险多目标优化调度模型。提出一种基于可行性和非劣性综合排序回溯搜索算法,从而实现对调度模型的高效准确求解。IEEE 30节点系统算例结果验证了所提方法的有效性和优越性。     

电力系统输电运行弹性空间建模与效益评估

电力负荷增长和新能源接入给电网安全、经济运行带来了新的挑战。为提高电网运行安全裕度,在更大空间内实现资源优化配置,需要在现有设备基础上,挖掘电网的电能输送潜力。为此,提出输电环节运行弹性空间的概念,以挖掘输电线路与联络线的运行弹性空间。文中提出两种提高输电运行弹性空间的方式及其建模方法:①基于转移分布因子,建立线路故障短时增容弹性模型;②基于互联外网静态等值模型,建立考虑外网运行约束的联络线调整弹性模型。在此基础上,提出考虑输电运行弹性空间的N-1安全经济调度优化模型。最后,通过IEEE 30节点与IEEE 9节点互联系统评估了输电运行弹性空间的效益。仿真表明,考虑输电运行弹性空间的调度方法相较于常规调度方法可有效提高风电消纳,降低电网运行成本。     

基于两阶段优化的分布式潮流控制器配置方法

分布式潮流控制器(DPFC)作为一种布点灵活、易扩展的分布式柔性交流输电系统(FACTS)设备,可有效改善潮流分布、提升系统承载能力。然而DPFC的潮流控制效果在极大程度上依赖于其配置方案。为此,基于混合整数线性规划方法构建了电网承载能力和DPFC配置最优的两阶段优化数学模型:第1阶段模型考虑电网约束及DPFC物理和运行特性约束,实现系统承载能力的最大化;第2阶段模型将系统最大承载能力作为运行条件,通过优化DPFC的投资费用,确定DPFC安装位置及容量的最优配置信息。IEEE-RTS79及某地区实际电网中的算例结果表明了所提方法的有效性和合理性。     

A new multi-objective fuzzy-GA formulation for optimal placement and sizing of shunt FACTS controller

The location and sizing of FACTS controllers for voltage stability enhancement is an important consideration for practical power systems. In this paper, a strategy for placement and sizing of shunt FACTS controller using Fuzzy logic and Real Coded Genetic Algorithm is proposed. A fuzzy performance index based on distance to saddle node bifurcation, voltage profile and capacity of shunt FACTS controller is proposed. The proposed technique can be used to find the most effective location and optimal size of the shunt FACTS devices. The proposed approach has been applied on IEEE 14-bus and IEEE 57-bus test systems. The application results are promising.     

考虑风电参与的黑启动方案

风电具有启动功率小、启动速度快的特点,安全、稳定地利用风电将有效加快电力系统恢复进程。考虑系统调频能力和机组爬坡能力约束,提出基于机会约束规划模型的风电参与黑启动最佳接入量评估方法,并对风电接入时机进行评估。为了有效发挥风电的作用,提出考虑风电参与黑启动方案的优化方法,对风电接入和负荷恢复进行分时步协调优化,制定出风电参与的最优黑启动方案。以含风电的IEEE 39节点系统为算例验证所提方法的可行性和有效性。     

计及直流调节能力的含风电电力系统储能优化配置

随着风电装机容量的不断增加,电力系统对储能等灵活性调节资源的需求增加.而交直流混联电网是实现大规模风电并网、输送和消纳的基础.针对上述背景,提出一种计及直流调节能力的含风电电力系统储能优化配置方法,在促进新能源消纳的同时减少储能投资成本.首先,考虑到风电功率和负荷具有随机性、不确定性等特点,通过场景分析法来处理风电和负...     

计及可用输电能力的含大规模风电的输电系统规划

大容量风力发电基地的快速发展给电力系统安全与经济运行带来了新的问题,对输电系统进行规划时,既要考虑具备足够的可用输电能力（available transfer capability, ATC）以容纳大规模风电并网, 又要避免输电容量过分冗余造成投资浪费。在此背景下, 针对含有大容量风力发电的电力系统, 提出了一种计及ATC的输电系统规划随机优化模型, 主要内容包括:（1）在考虑风速和负荷等随机变量之间相关性以及线路和发电机故障概率的基础上, 构造了ATC概率模型;（2）采用拉丁超立方采样和灵敏度分析相结合的方法求解ATC概率模型;（3）构建以输电线路投资成本最小和ATC期望值最大为目标的优化模型, 将输电系统规划的经济性和运行风险进行有机结合。采用遗传算法求解所建立的输电系统规划优化模型, 并用18节点和46节点算例系统说明所发展模型和方法的基本特征。     

考虑多安全性约束的风电场穿透功率极限研究

穿透功率极限是含风电场电网规划中的重要问题。本文从梳理风电场穿透功率的多种约束条件入手,建立了包含系统潮流平衡、支路潮流、常规机组出力等约束条件的风电穿透功率极限计算模型,在此基础上引入了风电波动导致的系统频率偏差及电压偏差等安全性约束条件。提出了基于系统惯性中心频率的频率偏差指标和基于系统线性化方法的电压偏差指标,从安全性角度考虑了风电接入容量的影响因素。采用遗传算法对模型进行求解,相关算例证明了该方法的准确性和合理性。     

考虑暂态稳定性的网储多目标双层优化

随着风电和负荷的不断发展,输电阻塞、弃风和运行安全等问题对电网规划提出了新的挑战。储能系统具有响应速度快、配置方便灵活、适用范围广等优点,在风电消纳、缓解输电阻塞、系统安全运行中发挥着重要作用。为提高电网输电能力和抗扰动能力,结合系统故障后的暂态运行特性,在规划和运行层面综合考虑电网输电能力、弃风水平和暂态稳定性,以系统建设运行指标和系统稳定指标为多目标建立双层网储联合规划模型。外层模型为考虑储能系统选址定容规划的多目标模型,内层模型为考虑机组组合问题的输电网扩容模型。为提高求解效率,将扩容线路潮流约束、储能系统充放电模型、机组发电成本曲线等进行线性化处理。采用NSGA-Ⅱ算法和GUROBI求解器求解所提模型,并利用改进Garver-6 节点系统进行算例分析,在不同场景下验证了所建模型的有效性和合理性。     

考虑风电消纳的电热混合储能系统优化定容方法

大规模风电并网影响了电力系统的安全稳定运行,导致电网出现弃风现象,限制了风电的发展。考虑电力系统与热力系统的协调运行,使用电热混合储能系统与电网进行电量交换可以有效提升风电消纳水平,文章提出了一种考虑风电消纳的电热混合储能系统优化定容方法。首先,基于历史风电数据对风电功率建模,获得满足并网要求的目标并网风电功率;随后,采用电储能、电锅炉和储热设备组成电热混合储能系统,建立考虑电热混合储能系统运行约束,以系统总成本最低为目标的优化定容模型,并求解出电热混合储能系统的经济优化定容结果;最后,使用某电热综合能源系统的实测数据进行仿真计算,算例结果验证了所提方法对电热混合储能系统优化定容的有效性,在提高系统风电消纳能力的情况下保证了系统整体的经济效益。