【作者】 夏艺；

【导师】 陈丽娟； 许晓慧；

【作者基本信息】 东南大学 ， 电力系统及其自动化（专业学位）， 2021， 硕士

【摘要】 配电网作为电网传递能量的重要一环,直接面向社会,其供电可靠性引起了人们广泛关注,停电事故的发生对经济生产和社会稳定造成的负面影响渗透到各行各业各个环节。而在当下新能源、分布式发电等快速发展的时期,配电网已呈现“多源性”特征,这使得配电网能够具备一定自治能力。因此,本文提出区域自治电网这一理念,将其作为对配电网的一种特殊形态补充,更是将其作为应对威胁供电可靠性的各类问题、全面提高配电网供电可靠性的一种有效方式。本文围绕区域自治电网进行研究并制定优化策略,从功能定位、元素分析、区域划分、能源部署、运行管理等角度展开研究。具体内容如下:(1)对区域自治电网进行整体架构分析。从以下几个方面进行展开:1)区域自治电网的概念及其形态研究;2)区域自治电网功能定位;3)提出区域自治电网优化策略;4)对区域自治电网所含元素进行分析并建模。(2)研究区域自治电网储能规划问题,基于区域自治电网的形态特征及功能定位提出储能规划策略,提升区域自治电网应对配电网故障的能力。首先提出了基于社团结构划分理论的配电网虚拟自治区域划分方法;在此基础上,计及虚拟区域边界约束条件和分区调控方式,构建计及经济性和自治性两方面的双层储能规划模型,外层以经济性最优为目标,将年综合成本作为目标函数,对接入各区域的储能额定容量、功率、位置进行规划;内层以自治性最优为目标,将网损和区域间功率交互成本作为目标函数优化储能的日充放电功率。采用改进双层混合粒子群算法对该储能规划双层模型进行求解。最终通过算例仿真分析,验证所提策略不仅实现了储能规划的经济性,也使区域呈现“对外单一可控性,内部紧密自治性”这一特征,提升区域自治能力。(3)研究区域自治电网孤岛区域划分策略。在输电系统或配电系统发生故障导致大停电事故发生的情况下,配电网利用DG的供电支撑能力,形成孤岛自治运行区域,实现负荷恢复供电,保障重要负荷供电。基于区域自治电网功能定位和负荷恢复目标,提出“搜索+调整”两阶段孤岛区域划分策略。第一阶段,首先基于负荷分级和DG分类制定搜索规则,其次采用Dijkstra算法搜索得出重要负荷最短恢复路径以及非可靠DG启动路径,形成可靠DG与非可靠DG联合供电区域,并进一步基于DG区域的剩余容量和邻接关系,按优先级搜索将其他负荷节点划入DG孤岛内,形成具有最大恢复范围的初始孤岛区域;第二阶段,考虑多个自治运行影响因素,构建计及经济性、安全性的孤岛区域优化模型,对孤岛区域的边界和区域内恢复负荷量进行动态优化调整,确保区域安全可靠自治运行,最终形成实时动态自治区域。通过算例仿真分析,验证所提策略既达到了发生故障时优先保障重要负荷供电的目的,也充分利用了DG供电能力达到了较高负荷恢复率,通过该策略所形成的自治运行区域也呈现出灵活性和安全可靠性。更多还原

【Abstract】 As an important part of the energy transfer of the power grid,the distribution network directly faces the society.Its power supply reliability has attracted widespread attention.The negative impact of the occurrence of power outages on economic production and social stability has penetrated into all sectors of all walks of life.In the current period of rapid development of new energy and distributed power generation,the distribution network has shown "multisource" characteristics,which enables the distribution network to have a certain degree of autonomy.Therefore,this article puts forward the concept of regional autonomous power grid as a special form of supplement to the distribution network,which is also a way to deal with various problems that threaten the reliability of power supply,and to improve the reliability of power supply of the distribution network.This article focuses on regional autonomous power grids to study and formulate optimization strategies,from the perspectives of functional positioning,element analysis,regional division,energy deployment,and operation management.The specific content is as follows:(1)Analyze the overall structure of the regional autonomous power grid.From the following aspects: 1)Research on the concept and form of regional autonomous power grid;2)Functional positioning of regional autonomous power grid;3)Propose regional autonomous power grid optimization strategies;4)Analyze and model the elements contained in the regional autonomous power grid.(2)Study the energy storage planning of regional autonomous power grids,and propose energy storage planning strategies based on the morphological characteristics and functional positioning of regional autonomous power grid,in order to improve the ability of regional autonomous power.Firstly,a method for dividing virtual autonomous regions of the distribution network based on the theory of community structure division is proposed.On this basis,considering the boundary constraints of the virtual region and the partition control method,a two-tier energy storage planning model that takes into account both economic and autonomous aspects is constructed.In the model,the outer layer model uses the minimum annual comprehensive planning cost as the objective function to plan the rated capacity,rated power,and location of the energy storage connected to each area;the inner layer model optimizes daily operation strategy with the objective of smallest network loss and power interaction cost between regions.The improved two-layer hybrid particle swarm algorithm is used to solve the two-layer model of energy storage planning.Finally,simulation examples verifies that the proposed strategy not only realizes the economical efficiency of energy storage planning,but also makes the virtual area present the characteristics of "single external controllability and tight internal autonomy" and improve regional autonomy.(3)Researches on the strategy for the division of isolated islands in regional autonomous power grid.In the case of a major power outage caused by a failure of the transmission system or the distribution system,the distribution network makes use of the support capacity of DGs to form island autonomous operation areas,which realizes the restoration of power supply to the loads in the island area by forming the island area autonomous operation,and guarantees the power supply of important loads.Based on the functional positioning of regional autonomous power grid and load recovery goals,a two-stage "search + adjustment" strategy for islanding regions is proposed.In the first stage,firstly formulate search rules based on load classification and DG classification.Secondly,use Dijkstra algorithm to search for the shortest recovery path of important loads and unreliable DG start path,forming a reliable DG and unreliable DG joint power supply area,and further based on the DG area’s remaining capacity and adjacency relationship,search for other load nodes into the DG island by priority search,forming the initial island area with the largest recovery range.In the second stage,considering multiple factors influencing autonomous operation,construct an optimization model of isolated island regions that takes into account economy and safety.Dynamically optimize and adjust the boundaries and load recovery amounts of island areas to ensure safe and reliable autonomous operation of the area,and finally form a real-time dynamic autonomous region.Through simulation and analysis of calculation examples,it is verified that the proposed strategy not only achieves the purpose of giving priority to the power supply of important loads in the event of a failure,but also makes full use of the power supply capacity of DG to achieve a higher load recovery rate.The autonomous operation area formed by this strategy also shows flexibility,safety and reliability.更多还原