微电网多时间尺度能量优化管理技术研究

 2022-02-14 20:08:59

论文总字数:35787字

摘 要

能源和环境问题逐渐成为各国经济和社会发展的瓶颈,以可再生能源为主要能源形式的微电网技术正在蓬勃发展,被了越来越多的研究和重视。微电网是以各类源、储、荷为主要单元的拓扑结构,能量管理是微电网稳定运行的重要基础。本文的研究方向集中在多时间尺度框架下并网式微电网的能量优化策略,具体工作如下:

1)考虑到能量优化对于功率预测值的依赖,分析各微电源发电特性并建立模型,明确各单元功率的影响要素。建立含有重要负荷、可切除负荷、可控制负荷的负荷模型,为实现发电侧和负荷侧配合的能量优化调度做了铺垫。

2)储能系统对于微电网的能量调控不可或缺,考虑储能的投资成本、运行成本、充放电对老化的影响,建立以锂电池作为储能单元的充放电模型,经济性模型和寿命模型。基于经济模型给出回收旧电池是否合算的判断标准;基于寿命模型对于新旧电池设置合适的运行约束条件,包括SOC和功率上下限等。

3)对现有的优化算法进行分析,实现用遗传算法求解的源-网协调的能量调度,该算法求解结果优于使用专业的求解器。建立了优化周期为24小时,时间步长为1小时的日前经济调度模型,以及优化周期为4小时,时间步长10min的日内滚动优化模型,优化周期越长能调度的资源越多,预测数据越不精确,周期短反之。储能倾向于在电网谷电价时充电,峰电价时放电,且新电池的响应速度比旧电池快。

4)建立源-网-荷协调的日前能量调度,算例含有柴油机和柔性负荷,优化结果充分体现了各个可调度单元对于电价的响应。储能在可再生能源发电量大、负荷低谷时充电,在发电机组功率较小、负荷高峰时放电;可控制负荷仅在网内功率富余时启动,赔偿电价较高的可中断负荷通常维持接入状态;微电网也可以通过在售电价格高的时段对大电网卖电获取利润。

关键词:微电网能量管理,储能模型,遗传算法,源-网-荷协调的调度,多时间尺度

Abstract

Energy and environmental issues have stifled the economic and social development in many countries. Meanwhile, micro-grid technology, with renewable energy as its main energy sources, is a booming industry, and has been widely valued and studied. Micro-grid is a well-developed structure based on various types of energy sources, storage devices and loads. Energy management is an important foundation for the stable operation of the micro-grid. On the premise of stable operation, energy management system for micro-grid (MEMS) ensures micro-grid to be more economic and reliable. Research of this dissertation is as follows:

  1. According to the features of different distributed generators, their mathematical models were built, and main influencial factors were anaslyzed. A load model based on flexible loads was also built to prepare for the energy management between sources and loads.
  2. Storage system is the main controllerable unit in micro-grid. Considering its different features from conventional generators, charge and discharge process, aging process and repairing cost, a detailed cost model was built, fitting both new storage and aging storage, and some suggestions for its economic usage were given. The method for storage's lifetime optimization was proposed, which gave some reasonable constraints for MEMS.
  3. Analyzing various optimization algorithm, Genetic Algorithm was applied to solve the micro-grid energy management model. The optimization result of GA was superior to that from optimization solvers. Energy management models of two time scale were proposed: dayahead model and intraday model, which guaranteed a realtime and accurate dispatch of energy devices. Storage system tends to charge when the price is low and discharge when the price is high, and the newer storage devive performs better than the older one.
  4. Considering price response, a dayahead model based on resectable loads, controllable loads and diesel generator is proposed. From results of this model: 1)storage device is .apt to charge when DGs generate abundant energy and load demand is smaller; 2)the controllable load starts only if there is a power surplus; 3)resectable load which has a higher cut-off price is less likely to be cut off; 4)the micro-grid earns a profit by selling electicity to bulk power system when the selling price peaks.

Keywords: MEMS, storage model, Genetic Algorithm, source-grid-load coordinate EM, multi-scale EM

目录

摘 要 I

Abstract II

第1章 绪 论 1

1.1 课题研究背景及意义 1

1.2 国内外研究现状 2

1.3 论文的研究工作与章节安排 4

第2章 微电源与负荷模型 6

2.1 微电源模型 6

2.1.1 光伏发电模型 6

2.1.2 风力发电模型 9

2.2 负荷单元模型 10

2.3 本章小结 10

第3章 储能单元模型 12

3.1 储能单元模型 12

3.1.1 储能技术总述 12

3.1.2 锂电池充放电模型 13

3.2 储能单元经济模型 14

3.3 储能单元寿命模型 18

3.4 本章小结 20

第4章 源-网协调的能量优化调度 21

4.1 优化目标及约束条件 21

4.2 优化算法的应用性分析 22

4.3 遗传算法的原理与实现 24

4.4 多时间尺度协调:滚动式日内优化模型 25

4.5 算例分析 27

4.5.1 日前优化调度 27

4.5.2 日内优化调度 33

4.6 本章小结 34

第5章 源-网-荷协调的能量优化调度 35

5.1 模型建立 35

5.1.1 基本调度策略 35

5.1.2 元件模型 35

5.1.3 目标函数与约束条件 37

5.2 算例分析 37

5.3 本章小结 40

第6章 总结与展望 42

6.1 论文工作总结 42

6.2 不足与展望 42

致谢 43

参考文献 44

绪 论

课题研究背景及意义

能源在一个国家的经济发展中扮演着举足轻重的角色,然而,这种高耗能的发展模式,往往伴随低效率的能源利用,在促进经济增长的同严重阻碍了社会的可持续发展。传统的能源结构已不能满足人类文明快速膨胀的需要,除了改进工艺水平,利用新的清洁能源,探索新技术变得十分迫切和必要。《2014年度世界能源展望》[[1]]再次将矛头指向能源紧张这一议题:温室气体的排放及空气污染问题严峻;到2040年,全球能源总需求增幅接近40%,其中煤炭增长率达15%,中国的煤炭占有率尤其高,其峰时需求额占全球需求50%。此外,以中国为代表的发展中国家对能源的利用方式较为落后,GDP对能源的依赖程度大,如图1-1所示。

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