【作者】 刘波；

【导师】 张焰；

【作者基本信息】 上海交通大学 ， 电力系统及其自动化， 2009， 博士

【摘要】 近年来,随着我国能源消耗的日益增大,以集中式单一供电方式为主要特征的电力系统所引起的环境问题、能源问题以及经济性问题等越来越引起人们的重视,同时为了有效提高能源利用效率和实现电力工业的可持续发展,我国必须加大对诸如微型燃气轮机、太阳能发电、风力发电、燃料电池等各种形式的分布式电源(Distributed Generation,DG)的开发和利用。鉴于DG具有能够安装在负荷中心、低投资成本、能及时跟踪负荷变化,以及提高系统供电可靠性等优点而具有很好的应用前景。通过全面了解不同类型的DG技术,对含DG的电力系统进行合理规划,研究其对电力系统的影响具有重要的理论价值和实际意义。本文主要针对含有风力发电、太阳能发电形式的DG的电力系统潮流、规划、可靠性以及稳定性进行研究,主要研究内容可概括为:(1)如何较为准确的预测风速,是风电场资源状况评估中比较难以解决的问题。本文以风速为研究对象,根据风速本身具有时序性和自相关性的特点,建立基于时间序列分析的自回归和滑动平均风速预测模型,提出采用长自回归计算残差校验算法进行模型定阶和参数估计。通过对实际风速数据进行测试,验证了本文所提出的预测计算方法的有效性。(2)风力发电和太阳能发电作为目前应用最广泛的两种DG形式,接入配电网后对配电网的潮流影响很大,因此有必要将二者结合起来研究,以提高配电网潮流计算模型的准确度。本文提出计及这两种DG的交直流混合迭代潮流计算方法。首先分析了风力发电机和太阳能电池接入配电网后在潮流计算方面所涉及的问题,然后构建含DG的潮流计算模型,并在此基础上,根据配电网特性对灵敏度分析法进行简化,使得能够快速求解断线故障模式下的配电网潮流。通过对测试系统的计算分析表明了文中所提方法的有效性。(3)在分析DG接入配电网前后对网络损耗影响的基础上,对配电网扩展规划中DG的选址和定容问题进行研究,提出基于混合模拟退火算法的改进粒子群算法来优化求解分布式电源选址和定容问题。该算法在粒子群个体寻优过程中采用Metropolis准则优选个体最优值,用其结果作为下一代群体中各个体的历史最优解,随着搜索的进行逐步定位在最优解附近区域并进行精确搜索,从而能够快速得到DG位置和容量问题的最优解。通过两个算例将所提出的算法与采用遗传算法、模拟退火算法的计算结果进行对比分析,表明本文算法的可行性和良好的寻优性能。(4)在考虑风速的时序性和自相关性、风电机组的功率特性以及强迫停运影响的基础上,建立基于蒙特卡罗方法的风电场可靠性评估模型,并将其与输电网可靠性模型相结合,在满足系统安全运行的前提下,进一步提出以输电网最大负荷供应能力为目标函数的考虑风电场影响的发输电系统可靠性评估模型,对反映风电场影响的相关可靠性指标进行了分析计算。(5)建立引入DG后的配电网孤岛划分问题,采用广度优先搜索技术求解该模型。此外,结合配电网孤岛运行方式,对孤岛形成后的负荷点可靠性指标进行分析,应用传统的故障后果分析方法和最小路算法对含DG的配电网供电可靠性进行评估,该评估方法可以用来研究DG本身的随机特性对供电可靠性的影响。以典型测试系统为算例验证了DG合理接入配电网后,可以提高配电网供电可靠性。(6)研究大型风电场接入电网后的系统小干扰稳定问题。以单个风力发电机为研究对象,考虑风力发电机传动轴柔性和桨距角控制,建立用于研究系统小干扰稳定性的风电场数学模型,推导出等值风力发电机的线性化方程,通过实际算例分析与各个发电机强相关的振荡模式、阻尼比等参数,探讨风力发电机出力及接入系统的距离等改变时对系统小干扰稳定性的影响。更多还原

【Abstract】 In recent years, with the rapid growth of energy consumption, the centralized and single power supply mode has caused many environmental issues, energy problems, as well as economic issues, which have aroused extensive concern in the international community. At the same time in order to effectively improve energy efficiency and realize sustainable development of the electric power industry, our country must step up the development and use of Distributed generations (DG). DGs include photovoltaic cells, wind generation, battery storage, fuel cell, etc. These units are usually sited at or near consumers to meet specific needs, low investment cost, be able to track the load changes in time, as well as improve system reliability, etc.With the penetration of DG technologies, DGs have good application foreground in power systems.Based on the introduction of various types of DGs, a systematic study on planning for grid-connected DG system and its impact on the power system has an important practical significance and theoretical value.This dissertation devoted to the research on load flow, power system planning, reliability, and stability studies containing DG (mainly wind and solar energy). The major research work is outlines as follows:(1) How to forecast wind speed accurately is a difficult problem to evaluate the status of wind energy resources.The paper takes wind speed as investigative object. Wind speed forecast model is built on the base of Auto-Regressive and Moving Average time series model by virtue of wind speed’s time-sequential and self-correlation. A long autoregressive residual error checking algorithm is applied for estimating parameters and calculating the model’s order. Based on an actual wind speed data for testing, the proposed method for wind speed forecast is analyzed to exhibit the effectiveness. (2) Wind and solar power are two types of DG most widely used at present. When wind and solar power are integrated into distribution network, it has great effect on load flow.Therefore, it is necessary that wind and solar power be integrated in research in order to enhance the accuracy of the load flow calculation model. The paper presents an AC-DC parallel iteration algorithm of load flow. First of all, the main problems of load flow are concerned when wind turbines and solar battery are integrated into distribution network, and then, the power flow calculation model is built including DG. On the basis of them, the sensitivity analysis method for distribution network is simplified in order to analyze the state of system in fault mode. The effectiveness of the proposed method is verified by the test system calculation analysis.(3) On the basis of analysing the influence of network loss when DG access to distribution network, the site and size of DG in distribution network expansion planning is researched.The paper presents a new algorithm to optimize the site and size of DG based on integrating the use of Simulated Annealing (SA) and Particle Swarm optimal (PSO) algorithm.The proposed algorithm adopts Metropolis criterion to search for individual optimum value in the individual optimization process and its result becomes basis for the individual optimal solutions of next-generation groups.With the search for the progressive position, the optimal solution is gradually located in the vicinity of the optimal solution, and can get the optimal solution of the site and size problems of DG quickly.With two numerical examples the superiority of the proposed algorithm is demonstrated in comparison with the genetic algorithms, simulated annealing algorithm. The calculation results show that the feasibility and good searching performance of the proposed algorithm.(4) On the basis of considering the time sequence and self-correlation of the wind speed, a reliability evaluation model of wind farms integration in power systems based on the Monte-Carlo simulation approach is proposed in this paper. Basing on these, a new reliability evaluation model in generation and transmission systems containing wind farms is proposed on the premise of the power system safety operation, in which the maximum load supplying capacity of transmission systems is used as the objective function, and the proposed model can be used to assess the influence when wind farms are integrated into transmission systems. Some reliability indices are analyzed and calculated to reflect the effects of wind farms. (5) The paper builds a divided island model including DG of distribution network. The breadth-first search technology are used to solve the problem.In addition, the paper presents a new reliability evaluation model considering the DGs, which can handle the influence of DGs on the distribution system through failure mode and effect analysis method and the minimal path method for the calculation of the distribution system with DGs.The calculating results indicate that the distributed generation connected to distribution network can improve the reliability of the distributed system.(6) The impact of large scale wind power integration on small signal stability problem is studied. The paper takes the wind generator as investigative object. A mathematical model of wind power generation sets for small signal stability analysis is established, which could consider its shaft and pitch control.With the solution of the eigenvalues, the analysis of oscillation modes, damp ratios are performed when operation parameters change such as the output of wind power, the distance to integration and so on.更多还原