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类型 基础研究 预答辩日期 2017-11-25
开始(开题)日期 2015-12-18 论文结束日期 2017-09-14
地点 动力楼318 论文选题来源 国家自然科学基金项目     论文字数 6.99 (万字)
题目 主动配电网重构与孤岛划分研究
主题词 主动配电网,分布式电源,网络重构,孤岛划分
摘要 近年来,随着传统化石能源的日渐衰竭,全球范围内对环境问题的广泛关注和电力科学技术的快速发展,以光伏发电、风力发电等可再生能源发电为主的分布式电源(Distributed generation,DG)技术成为国内外研究的热点,DG在电力系统内的渗透率也逐步提高。配电网接入DG并辅以主动、灵活、智能的运行控制手段,形成主动配电网(Active distribution network,ADN)。DG的接入改变了传统配电网的潮流和电压分布特性,可再生能源的随机性和间歇性也给配电网运行控制带来不确定因素。在高密度可再生分布式电源(Renwable DG,RDG)接入时,如何在保证电网运行安全的前提下尽可能多地消纳可再生能源、减少切机和能源浪费,是主动配电网面临的一个挑战。同时,RDG和储能的接入也使得负荷的供电路径多样化,对主动配电网提高供电可靠性、减少电网故障带来的停电损失也提供了新的机遇。另一方面,随着智能电网的建设和配电网馈线自动化水平的逐渐提高,主动配电网运行控制方法更加多样化,拓扑结构更加灵活多变,为应对高密度RDG接入带来的挑战和机遇提供了手段。 基于上述背景,本文从网络拓扑调整的角度对主动配电网的优化运行进行研究,通过正常运行状态下的拓扑优化,即网络重构,改善电网潮流和电压分布、提升电网对RDG的消纳能力;通过故障状态下针对RDG供电范围的网络拓扑优化,即孤岛划分,充分利用RDG和储能的持续供电能力、最大程度缓解电网故障带来的影响。本文的主要研究内容如下: 1)提出以提升分布式电源消纳为目标的静态重构方法。以消纳RDG功率最大为目标,建立了单时间断面网络静态重构模型。考虑了可再生能源出力和负荷功率预测的不确定性,并采用机会约束规划模型将随机优化问题转化为确定性优化问题。提出了基于改进智能算法的重构求解策略。借鉴大数据和统计分析的思想,引入皮尔森相关系数修正项对算法迭代过程提出了改进。 2)提出基于二阶锥规划的动态重构方法。以一日内主动配电网运行经济效益最高为目标建立了动态重构优化模型,提出了适用于网络结构灵活变化的拓展DistFlow潮流方程,并基于此建立了动态重构的运行约束表达式。引入虚拟“支路电压”的概念对电压降约束进行线性化处理,提出了基于“有功流”的辐射形拓扑线性约束方法,同时配合变量替换和约束松弛,建立了主动配电网动态重构优化模型的二阶锥规划形式。 3)提出基于能量指标的静态网孤岛划分方法。考虑到RDG、储能、电动汽车等分布式资源(Distributed energy resources,DER)和负荷的功率波动特性,建立了孤岛划分时段内各DER和负荷的能量指标,并提出了基于能量指标的孤岛划分两层优化模型。上层模型保持了传统孤岛划分背包树问题(Tree knapsack problem,TKP)的数学形式,下层模型对各孤岛进行功率调度和潮流检验,并提出了基于检验结果的上层模型的修正方法和孤岛运行调整策略。通过建立含能量约束、功率约束和能量转移约束的约束集,确保孤岛划分结果的合理性和有效性。 4)提出基于动态负荷权重的动态孤岛划分方法。对配电网故障后失电区域的拓扑结构进行动态优化,用单位功率停电损失作为负荷权重,结合不同种类电力用户的停电损失关于停电时长的特性,通过DER、网络结构和各类负荷的动态配合实现故障后配网总停电损失最小。首先基于统计数据对各类用户的停电损失函数进行拟合,引入图论相关概念建立了动态孤岛划分理论最优模型;其次在时间离散化、储能性能和用户停电次数的相关假设下提出了简化实用模型。考虑了DER和负荷功率的不确定性并采用解析法对不确定模型进行转化。提出了动态孤岛划分简化实用模型的启发式求解方法。
英文题目 Network Reconfiguration and Island Partition of Active Distribution Network
英文主题词 Active distribution network,Distributed generation,network reconfigruation,Island partition
英文摘要 With the gradually exhaustion of traditional fossil energy, the increasing global concerns of environmental protection and the rapid development of the electric power science and engineering, the distributed generation (DG) technology based on renewable energy sources such as photovoltaic power and wind power has become a hot research topic in recent years. The penetration of DG in power systems is also increasing continuously. The active distribution network (ADN) is formed by integrating DG to traditional distribution network, supplemented with active, flexible and intelligent control strategies. The integration of DG changes the characteristics of power flow and voltage profiles in traditional distribution networks, and the stochastic and fluctuation characteristics of renewable energy bring uncertainties to distribution network operation and control. With large scale of renewable DG (RDG) integration, it has become a challenge of ADN to consume as more renewable energy as possible and reduce the power curtailment on the premise of safety operation. Meanwhile, the integration of RDG and energy storage make the loads no longer have only a single power supply path, which brings new opportunity in ADN to improve the power supply reliability and decrease the customer interruption cost due to the network failure. On the other hand, with the construction of smart grid and the development of distribution automation, the control strategies of ADN are diversified and the network are more flexible, which provides the means for ADN to seizing the opportunity and facing the challenge due to the RDG integration. Based on the above background, this dissertation studies the operation optimization of ADN from the point of topology adjustment. By optimizing the network structure under normal operation condition, i.e., network reconfiguration, the power flow and voltage profiles can be optimized and the capability of ADN to consume the RDG can be improved. By optimizing the network structure under failure condition, i.e., island partition, the capability of RDG and energy storage to maintain an uninterrupted power supply can be fully utilized, and the impact of network failure can be alleviated. The contents of this dissertation are as follows. 1) A network reconfiguration method to increase the ADN’s capability to consume RDG is proposed. Aiming to maximize the RDG consumption in the ADN, a static network reconfiguration model for a single time section is built. The stochastic characteristics of RDG output power and load are considered, and the chance-constrained programming (CCP) is adopted to transform the stochastic optimization model to be a deterministic one. A reconfiguraiton strategy based on an improved intelligent algorithm is introduced. The intelligent algorithm is improved from the point of statistical analysis: the Pearson correlation coefficient is introduced to modify the iteration process. 2) A dynamic network reconfiguration based on second-order cone programming is proposed. Aiming to maximize the economic benefit of AND during a day, an optimal dynamic network reconfiguration model is built. An expanded DistFlow model which is suitable for flexible configuration of distribution network is proposed, based on which the operation constriants of the optimal model is given. The definition of “line voltage” is introduced to linearize the voltage magnitude drop constraint, and “active power flow” is introduced to linearize the radiality constraint. Togther with variable substitutions and constraint relaxation, the integrated model is transformed as a second-order cone programming problem. 3) An optimal static island partition algorithm based on energy indexes is proposed. A two-stage approach that integrates optimal island partition and power dispatch is proposed. Considering the power fluctuation characteristics of distributed energy resources (DERs) such as RDG, energy storage, electric vehicles (EVs), the energy indexes of the DERs and loads during the island partition period are defined, and a 2 stage optimal island partition method is proposed. The model in first stage maintains in a mathematical for of tree knapsack problem (TKP). Power dispatch and sequential power flow tests are given in the second stage, and the model modification method and island adjustment strategies are proposed based on the test result. By building a constraint set containing energy constraint, power constraint and energy transfer constraint, the island status is finally ensured to be feasible and optimized 4) A dynamic island partition method based on dynamic load weight is proposed. When a failure occurs in active distribution system, the network might be divided into several connected components, and topology of outage components is optimized. The total customer interruption cost is decreased by the cooperation of DER, network structure and loads considering the different interruption cost characteristics of multiple kinds of customers. Firstly, the interruption cost functions of customers are fitted, and the graph theory is introduced to build a theoretically optimal island partition model. Secondly, a simplified but practical model is derived based on the assumptions of time discretization, energy storage performance and customer interruption frequency. Fluctuation and stochastic characteristics of the renewable distributed generations and loads are considered and the stochastic model is transformed into a deterministic one by analytical method. A heuristic search algorithm based on the hill climbing method is proposed to solve the practical model.
学术讨论
主办单位时间地点报告人报告主题
东南大学 2016.04.14 南京 罗安 微网/分布式电站接入电网面临的电能质量问题及对策
东南大学 2016.01.06 南京 刘春华 Overview of Emerging Electric Machines for Sustainable Energy Conversion
中国电科院 2014.06.25 北京 朱俊澎 规模化电动汽车广泛随机接入的基础理论
东南大学 2015.04.19 南京 朱俊澎 消纳风电的热-电联合优化规划及运行
中国电科院 2015.05.11 北京 朱俊澎 含不确定性的配电网潮流计算
中国电科院 2016.08.05 北京 朱俊澎 基于负荷跟踪的配电网运行优化控制关键技术研究与开发
东南大学 2015.07.12 南京 王晓睿 Research focuses of Smart Grid: energy storage devices
东南大学 2015.01.06 南京 Richard A. Williams Feeding and Fueling by Unlocking the Cold Chain – the role of cryogenic energy storage systems
东南大学 2015.01.06 南京 Richard A. Williams Feeding and Fueling by Unlocking the Cold Chain – the role of cryogenic energy storage systems
     
学术会议
会议名称时间地点本人报告本人报告题目
中国电科院学术报告会 2016.10.08 北京 基于大数据的配电网基础计算与优化关键技术
IET RTDN 2015.09.23 英国 伯明翰 An improved PSO algorithm based on statistics for DNR to increase the penetration of DGs
东南大学学术报告会 2017.05.12 南京 配电网运行优化控制技术
中国电科院学术报告会 2017.03.01 北京 配电网快速重构与孤岛划分方法
     
代表作
论文名称
An improved PSO algorithm based on statistics for DNR to increase the penetration of DGs
Finite Action-Set Learning Automata for Economic Dispatch Considering EV and RES
 
答辩委员会组成信息
姓名职称导师类别工作单位是否主席备注
卫志农 正高 教授 博导 河海大学
丁孝华 正高 教授级高工 其他 国电南瑞科技股份有限公司配电/农电分公司
陆于平 正高 教授 博导 东南大学
吴在军 正高 教授 博导 东南大学
窦晓波 正高 教授 博导 东南大学
      
答辩秘书信息
姓名职称工作单位备注
杨燕 其他 研究生秘书 东南大学