Reconfiguration of distribution network for loss reduction and reliability improvement based on an enhanced genetic algorithm

Electrical distribution network reconfiguration is a complex combinatorial optimization process aimed at finding a radial operating structure that minimizes the system power loss or/and maximizes the system reliability while satisfying operating constraints. In this paper, a distribution network reconfiguration method is presented for both the indices of power loss reduction and reliability improvement. The enhanced genetic optimization algorithm is used to handle the reconfiguration problem so as to determine the switch operation schemes. Based on the information of a single loop caused by closing a normally open switch, we improve the algorithm on crossover and mutation operations of original Genetic Algorithms. The effectiveness of the proposed method is demonstrated on 33-bus, 69-bus, and 136-bus radial distribution systems.     

兼顾供电可靠性和经济性的多目标网络重构

提出了基于隐含并行寻优思想的兼顾供电可靠性提高和网损降低的配电系统多目标网络重构算法。该算法采用了大规模配电系统三相潮流计算和可靠性评估方法,实现了配电系统可靠性与经济性水平的综合最优化。该算法具有不依赖于网络开关的初始状态,也不受初始联络开关的操作次序的影响,可以高效地求解系统的有效解,实现多目标综合优化的特点。算例结果表明,该算法是灵活和高效的。     

考虑分布式电源和电动汽车集群调度的配电网络重构

随着分布式电源和电动汽车等灵活性电力资源大量接入配电网,对系统安全可靠性提出了更高要求。提出一种考虑分布式电源和电动汽车集群调度的配电网络重构方法,以提高系统可靠性和经济性。在考虑电压偏差的基础上,以故障停电损失成本作为衡量电网可靠性的经济性指标,对网络拓扑结构进行重新构建。首先以线路的开关状态、电动汽车充、放电状态及功率为决策变量,建立以综合成本最小为目标的配电网络重构模型;然后针对配电网络重构模型,采用共生生物搜索算法进行模型求解;最后,通过仿真算例验证了所提方法的有效性。     

Optimal operation of distribution networks

The objective of the analysis presented is to outline and validate a methodology for the optimization of MV distribution network operation. Loss minimization, taking into account the protective scheme applied, reliability and voltage quality aspects, are attained. Loss minimization is achieved by the installation of shunt capacitors and reconfiguration of the network. Two different reconfiguration methods are applied and compared. Special attention is given to the impact of network reconfiguration on the protective scheme applied, as well as on network voltage quality and reliability. Loads are assumed to be time variable, following typical daily curves. A general optimization method, suitable for overhead and underground networks, is outlined and validated through applications     

Fault tolerant control of a three-phase three-wire shunt active filter system based on reliability analysis

This paper deals with fault tolerant shunt three-phase three-wire active filter topologies for which reliability is very important in industry applications. The determination of the optimal reconfiguration structure among various ones with or without redundant components is discussed based on reliability criteria. First, the reconfiguration of the inverter is detailed and a fast fault diagnosis method for power semi-conductor or driver fault detection and compensation is presented. This method avoids false fault detection due to power semi-conductors switching. The control architecture and algorithm are studied and a fault tolerant control strategy is considered. Simulation results in open and short circuit cases validate the theoretical study. Finally, the reliability of the studied three-phase three-wire filter shunt active topologies is analyzed to determine the optimal one.     

基于博弈方法的含分布式电源配电网重构优化

智能配电网的发展要求在配电网重构中充分考虑分布式电源出力的不确定性,减小失电带来的影响,保证配电网供电的可靠性和经济性。在此背景下,把分布式电源出力不确定性虚化为“大自然”的博弈策略,与调度者的拓扑优化策略先后对策,构建了以重构费用最小为目标的配电网重构序贯行动博弈模型。然后通过改进的博弈树方法对重构的博弈模型进行求解,得到考虑了分布式电源出力不确定性的配电网重构方案。最后通过对IEEE 33节点配电系统的仿真分析,验证了所提出方法的有效性,并从经济性和可靠性方面对重构方案进行了鲁棒性分析。     

含微电网的配电网可靠性最优化

提出了一种含微电网的配电网可靠性最优化模型和算法。目的是在引入微电网后,在不增加投资的条件下,通过改变网络结构来达到可靠性提高的最大化,为规划运行人员提供决策参考。模型以系统平均停电频率指标、系统平均停电持续时间指标、系统平均供电不可用率指标以及系统平均供电量不足指标的加权组合的最小化为目标函数,以系统安全稳定极限以及微电网运行特点为约束条件。设计了基于可靠性的启发式的开关交换算法对模型进行求解。改进了传统的牛顿法,使之适用于含微电网的配电网的重构特点。算例分析表明所建模型在优化网络结构,改善负荷分布以及提高网络整体可靠性等方面具有积极作用。     

Optimal service restoration and reconfiguration of network using Genetic-Tabu algorithm

This paper represents an approach for service restoration and optimal reconfiguration of distribution network using Genetic algorithm (GA) and Tabu search (TS) method. Restoration and reconfiguration problems in distribution network are difficult to solve within feasible times, because the distribution network is so complicated with the combination of many tie-line switches and sectionalizing switches and also has to satisfy radial operation conditions and reliability indices. Therefore, this paper applied Genetic-Tabu algorithm (GTA) to find optimum value with reasonable computation time. The Genetic-Tabu algorithm is a Tabu search combined with Genetic algorithm to find a global solution. The case studies with 7-feeder model showed that not only the loss reduction but also the reliability should be considered at the same time to achieve the optimal service restoration and reconfiguration in the distribution network.     

基于改进引力搜索算法的配电网多目标优化重构

在含分布式电源(distributed generation,DG)的配电网重构中,综合考虑网络经济性、电能质量以及供电可靠性等因素,通过基于模糊满意度的多目标处理方法将多目标函数进行归一化处理,将精英策略思想引入到万有引力搜索算法中,并采用此改进引力搜索算法对问题进行求解。以IEEE 33标准节点系统为例进行网络重构,仿真结果表明,多目标重构后系统的网损有较大的降低,同时节点电压质量和供电可靠性也得到提高,从而验证了所提算法的有效性和可行性。对比其他算法,所提算法有效避免了结果陷入局部最优解,提高了算法的稳定性且具有较强的寻优性能。     

基于馈线偶的配网快速负荷均衡重构方法

为了实现配网重构的在线应用,使网络中负荷均衡,提高网络可靠性,本文提出了一种基于馈线偶的配网快速重构方法。该方法以馈线偶为单位,利用最佳转移负荷公式在馈线偶内转移负荷,以达到馈线偶内的快速负荷均衡。在此基础上,对全网进行负荷均衡化。全网均衡化按照馈线偶的负荷不均衡程度从重到轻依次进行,重构中通过对馈线偶优化标记的标定及消除,最终达到全网负荷均衡化的目的。算例分析表明本文方法快速有效,可以满足网络重构在线应用的要求。     

一种具有直观经济性特征的配电网重构方法

提出了一种具有直观经济性特征的配电网重构方法。首先,采用经济性评价方式构建了具有直观经济特征的、兼顾网损和可靠性的优化模型。其次,为快速方便地计算配电网可靠性,提出采用面向对象思想中的类描述配电网分块后得到的元件块,并按网络拓扑生成元件块的树形结构。最后,将生物地理学优化算法应用于求解配电网经济性重构模型。IEEE16节点系统的重构结果验证了所提方法的可行性和适用性。     

模糊遗传算法和蚁群算法相结合的配电网络重构

通过开关的优化组合可以提高配电系统运行的可靠性、电能质量和经济性。为改善配电网络重构模糊遗传算法的优化速度,提出了一种模糊遗传算法和蚁群算法相结合的方法。该方法将总的种群分为两部分进行搜索,一方面通过选择算子寻找总的种群中较优个体作为模糊遗传算法的子种群进行交叉、变异操作;另一面通过设定适应度函数阈值筛选总的种群中优秀个体,并将其适应度函数值对网络信息矩阵进行全局更新,用蚁群搜索另一部分子种群。该方法设定适应度函数阈值改进了蚁群算法的信息素更新机制;把模糊遗传算法和蚁群算法的子种群融合构成总的新种群,并用     

提高供电可靠性的配电网重构

本文从提高配电系统可靠性出发，研究满足运行约束条件下的配电网重构问题，并首次利用遗传算法进行供电可靠性最优的网络重构。算例结果表明，用该文提出的重构方法，不仅可提高配电系统供电可靠性，而且也降低了网损。     

配电系统联络开关的优化配置

将联络开关优化配置的目标设为以提高系统可靠性原则为前提 ,寻求使网络重构得到的系统网损最小的配置方案。提出了两个启发式准则 ,即根据联络开关的分类和待联接联络开关的端点的电压差来指导联络开关的优化配置 ,并采用一种新的高效并行的可处理大规模三相不平衡配电系统的网络重构算法来保证获得网络重构的优化结果。算例表明该启发式算法对三相平衡和不平衡系统都是快捷和有效的     

考虑事故–经济重构共同影响的配电网智能终端规划

随着智能电网建设的不断推进,信息系统与配电物理系统不断深入耦合,配电自动化程度势必越来越高,智能终端的规划设计在配电自动化建设发展中显得尤为重要。基于此,建立考虑事故–经济重构共同影响下的配电网智能终端双层规划模型。上层模型为系统综合投资成本和运行成本综合最优进行“二遥”(集遥信和遥测功能于一体的智能终端)、“三遥”(集遥信、遥测和遥控功能于一体的智能终端)终端选址、选型以及光缆铺设规划建模。基于上层规划结果,下层事故重构部分基于多场景事故停运时间分解法,结合各类可转移负荷的负荷–电源转移路径上智能终端配置状态,计及断路器是否支持遥控对系统可靠性造成的影响等,建立配电系统可靠性评估量化模型;下层经济重构部分则计及潮流约束、安全约束、拓扑约束和开关动作约束从而建立基于二阶锥松弛(second order cone programming,SOCP)的动态混合整数线性模型以分析规划结果在系统正常运行时的经济性。最终,整个双层模型采用离散二进制粒子群算法(discrete binary particle swarm optimization algorithm,BPSO)进行优化求解,并先后...     

基于模糊多目标协调优化的配电网络重构研究

配电网络重构通过改变开关的开合状态以提高供电的可靠性和经济性。建立以网损最小、馈线负载均衡指标最小、开关操作次数最少多个目标协调优化的配电网络重构的数学模型。引入模糊隶属度函数对各目标进行模糊化处理,根据模糊集理论的最大最小法则,将多目标优化问题转化为单目标非线性规划问题。应用禁忌算法对该配电网络重构模型进行优化求解。对某个69节点配电网络系统,比较分析了四种不同的优化方案,仿真结果验证了所提出模型和求解方法的正确有效。     

计及可靠性的配电网重构模型及其分阶段算法

提出一种计及可靠性的配电网重构模型和分阶段快速方法。通过可靠性指标体系的分析,提出选取平均供电可用率指标和系统供电量不足指标作为表征系统可靠性的核心指标,并考虑传统模型中的系统有功网损指标。以上述3个指标最优为目标函数,构造新的多目标重构模型。针对3个指标量纲的不同和各指标自身特点,构造各指标的归一化满意度函数。为减少...     

基于运行优化的含储能电力系统可靠性评估方法

针对传统可靠性评估方法容易导致停电损失的问题,提出基于运行优化的含储能的电力系统可靠性评估方法。首先,根据分布式电源出力建立概率模型,并在峰谷电价机制下,建立受利益驱动影响的储能概率模型;然后,根据故障类型细化故障隔离范围,对非故障隔离区域进行孤岛划分和功率匹配,减少停电损失;最后,提出了基于序贯蒙特卡罗的可靠性评估方法,通过仿真验证了该方法的有效性。     

基于运行优化的含储能电力系统可靠性评估方法

针对传统可靠性评估方法容易导致停电损失的问题,提出基于运行优化的含储能的电力系统可靠性评估方法。首先,根据分布式电源出力建立概率模型,并在峰谷电价机制下,建立受利益驱动影响的储能概率模型;然后,根据故障类型细化故障隔离范围,对非故障隔离区域进行孤岛划分和功率匹配,减少停电损失;最后,提出了基于序贯蒙特卡罗的可靠性评估方法,通过仿真验证了该方法的有效性。     

Analytical Complex Distribution System Reliability Evaluation Considering Stochastic Interruption Durations and Network Reconfigurations

A reliability enhancement scheme for an electric distribution system is impossible to be cost-effective without the guidance of accurate reliability index estimations. As one of the widely used basic reliability indices, average interruption duration is of foremost concern, due to being a straightforward indicator of the electric power supply quality in the aspect of customer satisfaction to the incident response capability of electric utilities to outage events. This paper proposed an analytical distribution system reliability evaluation method that allows for considering stochastic load point interruption durations together with stipulated network reconfiguration constraints. Through case studies on the Roy Billinton Reliability Test System, advantages of the proposed method over a traditional section technique-based reliability evaluation method are discussed. The proposed method is validated to yield more realistic estimations in the case of considering stochastic interruption durations and post-fault network reconfigurations, thus is expected to be capable of supporting economical system reliability-enhancing decision-making.