混合储能系统平抑风电场功率波动研究
发布时间：2018-08-06 12:38
【摘要】：风能作为一种蕴藏丰富的清洁可再生能源,是解决当前能源危机和环境恶化问题的一种有效途径,风力发电技术越来越受到世界各国的重视。风能具有很强的随机波动性,风电直接并网会对电力系统的安全稳定运行造成不良影响,甚至引发电网崩溃问题。随着大规模储能技术的日益成熟,在风电场装设一定容量的储能系统是解决风电并网波动问题的有效手段。单一类型的储能方式难以兼具大功率密度和高能量密度的优点,蓄电池和超级电容器组成的混合储能系统,能取长补短,发挥两者各自的优势,对风电功率波动的平抑效果较为理想。混合储能系统模型结构的搭建、蓄电池和超级电容器容量配置以及协调控制策略的研究,具有重要的意义。首先,简要介绍了铅酸蓄电池和超级电容器各自储能原理及储能特性。在比较已有的各种等效模型的基础上,本文铅酸蓄电池选用PNGV等效电路模型,超级电容器选择经典等效电路模型。在Matlab中搭建了蓄电池和超级电容器的单体仿真模型,仿真结果证明了模型的有效性。然后,提出一种蓄电池和超级电容器的容量配置方法。取某风电场实测风电功率数据为研究对象,根据傅里叶变换对其进行频谱分析,得到风电波动频率分布情况,作为混合储能系统波动功率分配的依据。综合考虑风电并网波动要求和储能容量配置经济性问题,得到对风电功率数据进行小波包分解的最佳层,并提出一种基于熵权法的小波函数优化选择方法。选择3组具有典型代表性的风电功率数据,用最优小波函数经小波包分解到最佳层,得到并网期望功率和各频率不同的波动分量。根据蓄电池能量密度大和超级电容器功率密度高的特点,将波动分量分为低频波动部分和高频波动部分,分别作为两种储能元件的平抑目标,并以此为基础经过分析计算,得到蓄电池和超级电容器的容量配置结果。最后,提出一种基于SOC优化的混合储能系统协调控制方法。根据SOC的大小将储能元件的工作区域划分为五个部分,再结合储能元件的实时充放电状态,把储能元件的工作状态分为正常工作状态和非正常工作状态。分析两种储能元件相互配合可能出现的所有非正常工作状态,通过实时检测SOC的大小,对非正常工作状态下储能元件的充放电参考功率进行重新分配,以保证SOC处于正常范围内。该控制方法能在保证平抑效果的同时尽可能延长储能元件的寿命。
[Abstract]:Wind energy, as a kind of abundant clean and renewable energy, is an effective way to solve the problem of energy crisis and environmental deterioration. Wind power generation technology has been paid more and more attention by the countries all over the world. Wind energy has a strong random volatility. Direct grid connection of wind power will have a negative impact on the safe and stable operation of power system, and even lead to the power network collapse. With the development of large-scale energy storage technology, the installation of a certain capacity energy storage system in wind farms is an effective means to solve the problem of wind power grid fluctuation. It is difficult for a single type of energy storage mode to have the advantages of high power density and high energy density. The hybrid energy storage system composed of batteries and supercapacitors can complement each other and give play to their respective advantages. The control effect of wind power fluctuation is ideal. The construction of hybrid energy storage system model, the capacity configuration of storage battery and supercapacitor and the study of coordinated control strategy are of great significance. Firstly, the energy storage principle and characteristics of lead acid battery and super capacitor are briefly introduced. On the basis of comparing the existing equivalent models, the PNGV equivalent circuit model and the classical equivalent circuit model for lead-acid batteries and supercapacitors are selected in this paper. The simulation model of battery and supercapacitor is built in Matlab, and the simulation results show the validity of the model. Then, a capacity configuration method for storage battery and supercapacitor is proposed. Taking the wind power data of a wind farm as the research object, the frequency distribution of wind power fluctuation is obtained according to Fourier transform, which can be used as the basis for the distribution of fluctuating power in hybrid energy storage system. Considering the requirements of wind power grid fluctuation and energy storage capacity allocation, the optimal layer of wind power data decomposition based on wavelet packet is obtained, and a wavelet function optimization selection method based on entropy weight method is proposed. Three groups of typical wind power data are selected. The optimal wavelet function is decomposed into the optimal layer by wavelet packet, and the fluctuation components of the desired power and frequency are obtained. According to the characteristics of high energy density of battery and high power density of supercapacitor, the fluctuating component is divided into low frequency fluctuating part and high frequency fluctuating part. The results of capacity configuration of batteries and supercapacitors are obtained. Finally, a coordinated control method for hybrid energy storage system based on SOC optimization is proposed. According to the size of SOC, the working area of energy storage element is divided into five parts. Combining with the real time charging and discharging state of energy storage element, the working state of energy storage element is divided into normal working state and abnormal working state. All abnormal working states of the two energy storage elements are analyzed. By detecting the size of SOC in real time, the charge and discharge reference power of the energy storage element under abnormal working condition is reallocated. To ensure that the SOC is within normal range. The control method can prolong the life of energy storage element as long as possible.
【学位授予单位】：湖南大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TM614
本文编号：2167759
[Abstract]:Wind energy, as a kind of abundant clean and renewable energy, is an effective way to solve the problem of energy crisis and environmental deterioration. Wind power generation technology has been paid more and more attention by the countries all over the world. Wind energy has a strong random volatility. Direct grid connection of wind power will have a negative impact on the safe and stable operation of power system, and even lead to the power network collapse. With the development of large-scale energy storage technology, the installation of a certain capacity energy storage system in wind farms is an effective means to solve the problem of wind power grid fluctuation. It is difficult for a single type of energy storage mode to have the advantages of high power density and high energy density. The hybrid energy storage system composed of batteries and supercapacitors can complement each other and give play to their respective advantages. The control effect of wind power fluctuation is ideal. The construction of hybrid energy storage system model, the capacity configuration of storage battery and supercapacitor and the study of coordinated control strategy are of great significance. Firstly, the energy storage principle and characteristics of lead acid battery and super capacitor are briefly introduced. On the basis of comparing the existing equivalent models, the PNGV equivalent circuit model and the classical equivalent circuit model for lead-acid batteries and supercapacitors are selected in this paper. The simulation model of battery and supercapacitor is built in Matlab, and the simulation results show the validity of the model. Then, a capacity configuration method for storage battery and supercapacitor is proposed. Taking the wind power data of a wind farm as the research object, the frequency distribution of wind power fluctuation is obtained according to Fourier transform, which can be used as the basis for the distribution of fluctuating power in hybrid energy storage system. Considering the requirements of wind power grid fluctuation and energy storage capacity allocation, the optimal layer of wind power data decomposition based on wavelet packet is obtained, and a wavelet function optimization selection method based on entropy weight method is proposed. Three groups of typical wind power data are selected. The optimal wavelet function is decomposed into the optimal layer by wavelet packet, and the fluctuation components of the desired power and frequency are obtained. According to the characteristics of high energy density of battery and high power density of supercapacitor, the fluctuating component is divided into low frequency fluctuating part and high frequency fluctuating part. The results of capacity configuration of batteries and supercapacitors are obtained. Finally, a coordinated control method for hybrid energy storage system based on SOC optimization is proposed. According to the size of SOC, the working area of energy storage element is divided into five parts. Combining with the real time charging and discharging state of energy storage element, the working state of energy storage element is divided into normal working state and abnormal working state. All abnormal working states of the two energy storage elements are analyzed. By detecting the size of SOC in real time, the charge and discharge reference power of the energy storage element under abnormal working condition is reallocated. To ensure that the SOC is within normal range. The control method can prolong the life of energy storage element as long as possible.
【学位授予单位】：湖南大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TM614
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