混合式孤岛检测方法的研究

发布时间：2018-01-06 07:30

本文关键词：混合式孤岛检测方法的研究　出处：《西南交通大学》2017年硕士论文　论文类型：学位论文

【摘要】：随着煤、石油、天然气等不可再生能源的日益枯竭,生态环境的日益恶化,电力负荷的快速增长,分布式发电系统在世界各国得到了快速的发展,因此对分布式发电系统并网稳定性的研究十分必要。非计划孤岛的产生将会对电力系统造成很大的危害,所以准确、快速地检测出非计划孤岛具有重要的理论现实意义。本文通过分析大电网断开后功率缺额对频率和电压的影响来阐释分布式发电系统孤岛检测的原理。归纳了国内外关于孤岛检测方法的相关标准,分析了几种用于判断孤岛检测盲区范围的坐标系法。主要研究过/欠压、过/欠频法和频率变化率法两种被动式检测法和主动频率偏移法(AFD)、带有正反馈的主动频率偏移法(AFDPF)和滑模频率偏移法(SMS)三种主动式检测方法的检测原理,并利用坐标系法描述它们的检测盲区。研究了主动式检测方法扰动参数设置对其检测性能的影响,确定最优扰动参数。针对被动式和主动式检测方法存在的不足,研究了将过/欠压、过/欠频法和带正反馈的主动频率偏移法(AFDPF)相结合的混合式孤岛检测方法。该方法通过盲区判别式分析系统的运行状态,来决定是否引入扰动电流利用带正反馈的主动频率偏移法(AFDPF)进行孤岛检测。本文通过对比分析选取了一种新型扰动电流的主动法与被动法进行混合使用。该方法通过在参考电流波形的正负半周期部分加入负的阶跃扰动,使并网公共节点处电压的正半周期幅值减小,负半周期幅值增大,当满足负半周期电压幅值的绝对值大于正半周期电压幅值的周期次数连续累计达到阈值,将判定为孤岛状态,断开并网逆变器。利用MATLAB验证了该方法的有效性和可行性。并且对比验证了该方法比之前的混合式检测法具有更好的电能质量,以及较小的检测盲区。
[Abstract]:With the depletion of non-renewable energy such as coal, oil and natural gas, the deterioration of ecological environment and the rapid growth of power load, distributed power generation system has been rapidly developed in the world. Therefore, it is necessary to study the stability of distributed generation system. The generation of unplanned island will cause great harm to power system, so it is accurate. Rapid detection of unplanned islands is of great theoretical and practical significance. This paper explains the principle of distributed generation system islanding detection by analyzing the influence of power gap on frequency and voltage after large power grid break. Internal and external standards on islanding detection methods. This paper analyzes several coordinate system methods used to judge the blind area range of isolated island detection. Two passive detection methods and active frequency offset method AFDs are mainly studied, including overvoltage / undervoltage method, over-frequency method and frequency change rate method. The principle of active frequency migration with positive feedback (AFDPF) and sliding mode frequency offset (SMS). The method of coordinate system is used to describe their detection blind area, and the effect of disturbance parameter setting of active detection method on its detection performance is studied. The optimal disturbance parameters are determined. Aiming at the shortcomings of passive and active detection methods, the overvoltage / undervoltage is studied. A hybrid islanding detection method combined with overpass / underfrequency method and active frequency shift method with positive feedback (AFDPF) is presented, which analyzes the running state of the system by blind area discriminant method. To determine whether to introduce disturbance currents using active frequency offset with positive feedback (AFDPF). In this paper, a new active and passive method of disturbance current is selected for mixed use. This method adds negative step perturbation to the positive and negative half period of the reference current waveform. The positive half-period amplitude of the voltage at the grid-connected common node is reduced, and the negative half-period amplitude is increased. When the absolute value of the negative half-period voltage amplitude is larger than the positive half-period voltage amplitude, the accumulative period number continuously reaches the threshold. The MATLAB is used to verify the effectiveness and feasibility of the proposed method, and compared with the previous hybrid detection method, the proposed method has better power quality. And small blind area.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM73

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