多逆变器并网光伏电站动态孤岛检测方法研究

发布时间：2018-03-15 19:54

本文选题：孤岛检测　切入点：多逆变器　出处：《沈阳工业大学》2017年硕士论文　论文类型：学位论文

【摘要】：随着能源的短缺,光伏、风能等清洁能源日益受到青睐,近些年,光伏并网发电技术迅速发展。孤岛保护作为光伏并网系统的一项必备保护,其检测方法及方法改进的研究一直受到广泛关注。当光伏并网系统的大电网断开,光伏单独为负载供电,此现象称为孤岛现象,孤岛发生会对检修人员和用电设备均造成伤害,所以必须及时检测出孤岛现象,并采取相应的保护措施,孤岛检测方法的研究具有实际意义。现有的孤岛检测主要是针对单逆变器并网条件下孤岛检测方法或者改进的方法的研究,然而随着光伏容量的增加,逆变器台数的增多,多逆变器孤岛检测也随之面临更多的问题。本文首先对单逆变器并网孤岛检测方法进行了详细的分析,随后对多逆变器并网孤岛检测问题开展研究,主要内容如下:(1)研究建立多逆变器采用主动频移法相互影响和作用机理模型,对多逆变器并网盲区变化机理进行分析(2)针对多逆变器并网孤岛检测特性,结合仿真和实测数据进行分析,研究基于小波分析的多逆变器并网孤岛特征向量的提取方法;(3)研究基于小波变换与支持向量机的多逆变器并网孤岛检测法,应用支持向量机建立所提取的特征量的分类模型及求解方法,对多逆变器并网孤岛进行判断。仿真结果表明,基于支持向量机的多逆变器并网孤岛检测算准确率高,稳定性好,能够有效区分孤岛和非孤岛两种不同运行状态。
[Abstract]:With the shortage of energy, photovoltaic, wind energy and other clean energy are increasingly favored. In recent years, photovoltaic grid-connected power generation technology has developed rapidly. The research on the detection method and method improvement has been paid more and more attention. When the large grid of photovoltaic grid-connected system is disconnected, the photovoltaic power supply for the load alone, this phenomenon is called "isolated island phenomenon", and the occurrence of isolated island will cause harm to maintenance personnel and electric equipment. So we must detect the phenomenon of isolated islands in time and take corresponding protective measures. The research of islanding detection method is of practical significance. The existing islanding detection is mainly aimed at the islanding detection method or the improved method under the condition of single inverter grid-connected. However, with the increase of photovoltaic capacity, the number of inverters increases. The islanding detection of multi-inverter also faces more problems. Firstly, the detection method of single-inverter grid-connected islanding is analyzed in detail, and then the detection problem of multi-inverter grid-connected islanding detection is studied. The main contents are as follows: 1) the model of interaction and action mechanism of multi-inverter using active frequency shift method is established, and the mechanism of blind zone change of multi-inverter grid-connected is analyzed. Based on the analysis of simulated and measured data, this paper studies the method of extracting the eigenvector of multi-inverter grid-connected islanding based on wavelet analysis) and studies the detection method of grid-connected islanding of multi-inverter based on wavelet transform and support vector machine. The classification model and solution method of the extracted feature are established by using support vector machine. The simulation results show that the detection accuracy and stability of multi-inverter grid-connected island detection based on support vector machine are high. It can effectively distinguish two different operation states: isolated island and non-isolated island.
【学位授予单位】：沈阳工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM464;TM615

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