智能配电网中分布式电源并网的思考

智能配电网是统一坚强智能电网的重要组成,是智能电网中连接主网和面向用户供电的重要组成部分。而接纳大规模分布式电源的灵活运行和操作,是智能配电网建成的重要特征之一。本文综合阐述和分析了分布式电源并网的相关内容,介绍了分布式发电技术及相关特性,结合具体算例,重点分析了并网带来的影响,指出智能配电网优化规划的问题和主要研究思路和方法,综合分析分布式并网的保护与控制,为未来分布式电源并网的深入研究和工程实践做铺垫。     

Evaluation of cost and reliability of power systems with large numbers of distributed generators

The authors have proposed the Flexible, Reliable and Intelligent ENergy Delivery System (called “FRIENDS”), which is a new concept for future power distribution systems. Also, a “micro grid” which is a similar concept to FRIENDS has been developed. In a micro grid, an independent distribution system can be constituted by a number of distributed generators. In this paper, FRIENDS, Micro grid, and conventional distribution systems are compared quantitatively in supply reliability and system cost through time sequential Monte Carlo simulations. In addition, for cost evaluation, interruption costs are included to show risk incurred by unsupplied energy. Finally, the authors search for preferable form with install and operation of distributed generators and network composition according to social cost including interruption cost and system cost. © 2009 Wiley Periodicals, Inc. Electr Eng Jpn, 167(2): 28–37, 2009; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20659     

智能配电网研究热点

智能配电网是智能电网的重要组成部分。随着电力生产形式、传输模式和电能利用方式的变化,配电网发展和运营不仅经历着原有技术和设备的升级改造,同时也面临着分布式电源接入、电力市场改革和高新技术集成与应用等许多新的问题和挑战。从能量、信息、市场三个方面介绍了智能化配电网的典型特征,在此基础上指出了配电网在网络规划、自愈控制、态势感知、资产管理、信息通信、分布式电源及储能等方面的关键技术,提出了智能配电网技术发展路线,为相关研究提供了参考。     

基于区块链的智能电网分布式资源管理研究

针对智能电网中分布式能源系统存在的管理困难,电力资源难以调度等问题,提出了一种基于区块链技术的电力网络管理系统。使用以太坊作为开发平台,建立分布式能源的电力交互管理区块链。使用股权证明(PoS)变异算法确立区块链中发用电双方共识机制,指定交易双方中的记账人;通过K-means聚类算法和粒子群优化算法(PSO)来设计分布式电能调度策略,进一步保障电网中能源交易分配的可靠性,最终实现电力运营智能合约下分布式能源的有效管理。实验结果表明：在智能电网中部署电力交互管理区块链,有效解决了分布式能源交易难达成,耗时长的问题,提高了电网中资源管理的合理性。     

联网分布式发电系统规划运行研究

分布式发电（DG）与输电网联合供电成为电力系统发展趋势。输电系统与DG联合供电的规划、运行分析对满足可靠性条件下的经济供电尤为重要。文中针对远离发电中心、与输电系统弱连接的配电系统,为了满足负荷增长要求,以DG投资费用和向输电网购电费用最小为优化目标,分别对输电网正常运行且价格固定、考虑停运状态和实时电价3种典型输电网情况下联网DG系统进行规划。通过应用启发式算法,得到了各种情况下系统最优供电方案。根据不同情况下系统运行性能分析,定量讨论了输电网停运、实时电价以及可再生能源随机发电对分布式电源类型、容量等规划运行结果的影响,优化结果体现了联网DG系统联合供电优势。     

智能用电技术背景下的配电网运行规划研究综述

为适应大规模分布式电源、储能、电动汽车接入配电网后发电方式和用电行为的改变,智能用电技术成为当前及未来智能电网研究的趋势。基于智能用电技术的内涵及核心特征,从需求侧响应、电能质量调控、可再生能源消纳、最优潮流控制、设备利用率提升方面,综述了配电网灵活优化运行的应用需求;考虑配电网运行与规划的相互影响,从分布式电源规划、配电网规划以及储能和电动汽车规划3个方向对当前规划思路和研究现状进行总结分析。结合源网荷供需灵活互动对配电网运行规划提出的挑战和未来配电网发展趋势,提出智能用电技术背景下配电网运行规划中需要进一步深入研究的问题。     

孤岛状态下含分布式电源的配电系统可靠性分析

分析了孤岛状态下含分布式电源的配电系统可靠性。针对配电网孤岛运行的特点,提出了可靠性分析的复合随机性负荷模型,提出了既能反映系统充裕度又体现动态特性的可靠性计算方法和衡量指标。计算结果表明,所提的模型、计算方法和衡量指标能充分反映分布式电源在不同程度上提高配电系统的可靠性,为系统的规划设计提供了重要参考。     

系统安全背景下未来智能电网建设关键技术发展方向——印度大停电事故深层次原因分析及对中国电力工业的启示

从外部环境以及内部生产运行中的管理层面和技术层面对本次印度大停电事故的原因进行了深入分析,从管理层面和技术层面分别提出了促进中国电力系统安全稳定运行的基本思路。同时,考虑到电网智能化是未来电网发展的趋势,具有坚强、自愈等特点的智能电网能够有效抵御电网安全风险,提出了基于系统安全的中国未来智能电网建设关键技术发展方向,包括分布式发电并网技术、智能配电技术、智能用电技术和电力系统储能技术,能够为中国下步智能电网发展及电力系统安全稳定运行提供借鉴和参考。     

Day-ahead optimal charging/dischargingscheduling for electric vehicles inmicrogrids

Microgrid as an important part of smart grid comprises distributed generators (DGs), adjustable loads, energy storage systems (ESSs) and control units. It can be operated either connected with the external system or islanded with the support of ESSs. While the daily output of DGs strongly depends on the temporal distribution of natural resources such as wind and solar, unregulated electric vehicle (EV) charging demand will deteriorate the unbalance between the daily load curve and generation curve. In this paper, a statistic model is presented to describe daily EV charging/discharging behaviors considering the randomness of the initial state of charge (SOC) of EV batteries. The optimization problem is proposed to obtain the economic operation for the microgrid based on this model. In dayahead scheduling, with the estimated power generation and load demand, the optimal charging/discharging scheduling of EVs during 24 h is achieved by serial quadratic programming. With the optimal charging/discharging scheduling of EVs, the daily load curve can better track the generation curve. The network loss in grid-connected operation mode and required ESS capacity in islanded operation mode are both decreased.     

基于改进蝙蝠算法的配电网分布式电源规划

合理规划接入电网的分布式电源能够提高能源利用效率,提高电力系统运行的经济性、灵活性和可靠性。建立了以分布式电源建设和运行总费用最小、系统网损最小、静态电压稳定指标最大为优化子目标的多目标规划模型。采用了一种新的仿生算法--蝙蝠算法,并针对蝙蝠算法的不足之处进行了改进,有效地解决了该算法易陷入局部最优、后期收敛速度慢等问题。通过14节点配电网测试系统进行了分布式电源选址和定容仿真分析。仿真结果表明,与传统的蝙蝠算法、粒子群算法相比,采用改进的蝙蝠算法能够更好、更快地得到分布式电源接入配电网的最优规划方案,验证了算法的正确性和可行性。     

基于分时电价和需求响应的家庭微电网系统协同控制策略及其实现

家庭微电网是智能配电网的重要组成部分和主要建设内容,随着智能电网的不断发展,家庭居民用电将参与电网的优化调度运行。为了适应社会的这种需要,首先以家庭可调度负荷、电动汽车和家用蓄电池工作状态作为约束条件,以用户用电成本最低和净负荷曲线平坦度为优化目标,建立了家庭微电网系统优化调度模型。其次,结合空调和热水器的工作负荷特性,提出了一种基于分时电价和需求响应的家庭微电网系统协同控制策略。对以北京市某居民小区的典型家庭微电网系统为实例的分析结果表明,采用基于所提出的优化调度模型的家庭微电网系统,可以实现对分布式光伏发电、家用蓄电池、电动汽车、家庭负荷设备的优化调度和控制。     

Planning for distributed wind generation under active management mode

In the smart grid (SG), the active management (AM) mode will be applied for the connection and operation of distributed generation (DG), which means real time control and management of DG units and distribution network devices based on real time measurements of primary system parameters. In this paper, a novel bi-level programming model for distributed wind generation (DWG) planning under AM mode is put forward. The model takes the maximum expectation of net benefit of DWG as the upper level program objective, and takes the minimum expectation of generation curtailment as the lower level program objective. The impact of active management algorithm on improvement of branch power flow and node voltage is taken into account. A hybrid algorithm combining the plant growth simulation algorithm (PGSA) with probabilistic optimal power flow (POPF) algorithm is presented to solve the optimal planning of DWG under AM mode. The case studies have been carried out on a 33-node distribution network, and the results verify the rationality of the planning model and the effectiveness of the proposed method.     

我国智能配电技术展望

当前国际上以提高供电质量和可靠性,解决分布式能源分散化小容量多数量接入为目的的智能配电网受到人们越来越多的重视,从而提出了规划和发展智能电网的迫切需求。鉴此,从智能配电网的优化规划和自愈结构设计、智能配用电的量测和通信技术、智能配电的信息系统、智能配电网的高级配电自动化技术、智能配用电新技术与新装备等几个方面,对适合中国国情的智能配用电技术的发展作了展望。     

智能配电网优化调度设计及关键技术

含多类型分布式电源和多样性负荷的智能配电网迫切需要优化调度以实现各种资源的优化配置,近些年配电自动化系统和信息系统的建设也为配电网优化调度的实现提供了基础。根据智能配电网实际需求,文中提出了配电网优化调度设计框架,以实现对智能配电网多种元素的全局优化调度。首先分析了配电网态势感知和配电网运行趋势分析两个配电网优化调度基础技术,然后提出了配电网优化调度的总体目标,给出了配电网优化调度的框架设计和基本功能,主要包括优化手段、优化内容、人工决策等方面,并分析了实现配电网优化调度的6项关键技术。     

Adaptive intelligent techniques for microgrid control systems: A survey

This paper introduces a survey on the adaptive and intelligent methods that have been applied to microgrids systems. Interestingly, the adaptive technique is effectively exercised in various control issues including stability, tracking error, and parameter uncertainties. Adaptive control has been extremely developed by using intelligent algorithms to automatically tune the control parameters namely fuzzy logic, particle swarm optimization, bacterial search algorithm, and etc. The objective is to evaluate and classify the design control methods and evaluation algorithms for the microgrid systems to maintain stability, reliability, and load variations by adjusting the controller parameters especially in standalone operation mode. The stability of islanded microgrids are constantly impacted by the related loads. A significant part of the research on an islanded microgrid involves droop control technique. In normal operation, distributed generation units and storage units provide power quality control. Once a shutdown is occurred, microgrid can be isolated from the main grid and operate in a local grid to support the local loads. Thus, distributed generations co-operate storage units to sustain the stability of the islanded microgrid.     

Optimal Energy Management for Smart Grid System Considering Battery Characteristics

This paper discusses optimal energy management considering battery characteristics for smart grid and microgrid systems. Energy storage systems are very important for energy peak shifting and peak load cutting in microgrid and smart grid systems, but optimal battery formulation and energy management in the use of expensive energy storage system and methods of taking account of battery characteristics are still in the developmental stage. First, the optimal battery placement for a smart grid system with lithium‐ion batteries is considered as a means of lifetime extension. The battery choice index for this optimal battery utilization problem of optimal energy management is discussed. Second, a smart grid system with a distributed battery system for grid frequency control with consideration of distributed control and battery characteristics is discussed. Optimal controllers for distributed battery systems to reduce the battery load and to expend the battery lifetime are designed. Simulations are used to demonstrate the effectiveness of the proposed method in comparison with conventional methods.     

分散式发电可作为应对电网大面积停电的重要措施

分散式发电是大电网系统的有益补充。介绍了分散式发电的基本概念、特点、运行方式,以及微型燃气轮机、燃料电池等分散式发电机组,分析了我国发展分散式发电技术的必要性和重要意义。针对我国南方地区电网大面积停电的教训．认为大电网系统和分散式发电系统相结合是提高电力系统安全性和可靠性、保障国家电力安全的重要措施。     

Power Electronic Drives,Controls, and Electric Generators for Large Wind Turbines–An Overview

Abstract—Wind represents a major and growing source of renewable energy for the electric power systems. This article provides an overview of state-of-the-art technologies and anticipated developments in the area of power electronic drives, controls, and electric generators for large multi-megawatt wind turbine systems. The principal components employed in a turbine for energy conversion from wind to electricity are described, and the main solutions that are commercially available are briefly reviewed. The specific issues of complex mission profiles, power codes, and reliability are discussed. Topics of power electronics, ranging from devices to circuit topologies, and similar matters for electric generators, together with results of optimal design studies are included. It is shown that the individual power rating of wind turbines has increased over the years, and technologies required to reach and exceed a power rating of 10 MW are discussed. The role of power electronics for improving the operation of wind turbines and ensuring compliance with power grid codes is analyzed with a view at producing fully controllable generation units suitable for tight integration into the power grid and large-scale deployment in future smart power systems.     

基于一体化思维的主动配电网设计方法研究

主动配电网是智能电网的重要组成部分,对其进行设计需要贯穿一体化思维。对主动配电网的定义和特征进行介绍,分析主动配电网的设计要点与要求,提出基于"分步推进"和"一步一反馈"的渐进优化式总体设计思路。在前述工作基础上勾画出统筹分布式电源接入、实时数据采集、配电网自动化配置、一次接线优化等多个层面的主动配电网一体化设计流程。     

一种考虑线损最优的配电网新能源聚类规划方法

当前以风电、光伏为代表的分布式电源在配电网中的占比越来越大,其对电网规划的合理性及可靠性也提出了较高要求。该文提出一种基于k-medoid聚类的配电网分布式发电规划方法,采用轮廓系数法确定最优的聚类个数,以配电网线损最优为优化目标,以配电网线损灵敏度因子作为聚类特性指标,得到分布式发电最优规划位置;并提出基于节点有功变化的部分线损计算策略以获得分布式发电的最优规划容量。最后,以IEEE33节点系统作为测试系统进行了分析。结果表明,所提方法不仅具有较高的计算效率,同时能够一次性给出多个特征指标下的综合最优接入方案,具有较强的实用性。