光伏并网发电系统的孤岛检测技术研究

发布时间：2018-01-11 16:04

本文关键词：光伏并网发电系统的孤岛检测技术研究　出处：《中国石油大学(华东)》2014年硕士论文　论文类型：学位论文

【摘要】：随着光伏产业的迅猛发展和国家政策对光伏并网的大力扶持,光伏并网技术成为研究热点之一,完善的孤岛检测技术是光伏并网发电系统实现安全可靠运行所必须具备的功能。本论文以单相光伏并网发电系统为研究平台,对光伏并网发电系统的孤岛检测技术进行了深入研究。本文对孤岛检测技术的若干理论问题进行了详细的分析,建立了孤岛检测数学模型,深入分析了各国孤岛检测标准,并将孤岛检测时间和低电压穿越技术要求相结合,给出了光伏并网系统发生孤岛时更为合理的动作时间,并对基于盲区理论的孤岛检测评价方法进行了系统地分析。被动式孤岛检测技术由于其实现简单,经济适用,虽存在一定的检测盲区,但仍被广泛运用,而电压幅值、频率提取是关键。本文重点对数字锁相环、强跟踪滤波器算法和二阶广义积分器锁频环三种电压幅值、频率提取方法进行了理论分析和仿真研究,并对比分析了各自的优势和存在的问题。综合考虑算法快速性、准确性及稳定性,首次将多通道二阶广义积分器锁频环应用于被动孤岛检测中,并搭建了单相光伏并网发电系统的孤岛检测仿真模型,实验结果证明了该算法在被动孤岛检测中能准确、快速提取幅值和频率,进而有效检测到孤岛的发生。被动孤岛检测无法解决功率匹配下的检测盲区问题,主动孤岛检测意在通过加入扰动来打破功率平衡,进而检测出孤岛发生。首先对主动移频法进行了理论分析和仿真研究,通过仿真结果分析了其优势及存在的弊端。在以上研究基础上,本文提出了一种新的孤岛检测方法即间歇性频率扰动法,该算法锁相环节采用多通道SOGI-FLL,可更为准确地对电压幅值和频率进行提取;采用若干个固定周波给予频率扰动,避免了过零检测易受干扰的问题;间歇性扰动改善了由于连续扰动带来谐波畸变率大的问题;适当加入幅值扰动,频率和幅值扰动双管齐下,进一步提高了孤岛检测的可靠性,仿真结果验证了该算法的有效性。搭建了基于可编程直流源的光伏阵列模拟实验装置,通过开环和闭环实验验证了该装置模拟效果的准确性和快速性,同时搭建了小型单相光伏并网发电系统硬件实验系统,完成了并网实验,为孤岛检测的后续研究提供了硬件平台。
[Abstract]:With the rapid development of photovoltaic industry and national policies to support photovoltaic grid, photovoltaic grid-connected technology has become one of the research hotspots. Perfect islanding detection technology is a necessary function for the safe and reliable operation of grid-connected photovoltaic power generation system. This paper takes single-phase photovoltaic grid-connected power generation system as the research platform. The islanding detection technology of grid-connected photovoltaic power generation system is deeply studied. In this paper, some theoretical problems of islanding detection technology are analyzed in detail, and a mathematical model of islanding detection is established. The detection standards of islanding are deeply analyzed, and the detection time of islanding is combined with the technical requirements of low voltage traversing, and the more reasonable action time is given when the photovoltaic grid-connected system occurs islanding. And based on blind zone theory of isolated island detection evaluation method is systematically analyzed. Passive isolated island detection technology because of its simple realization, economic applicability, although there are certain blind areas, but still widely used. The voltage amplitude and frequency extraction is the key. This paper focuses on the digital phase-locked loop, strong tracking filter algorithm and second-order generalized integrator frequency-locked loop voltage amplitude, frequency extraction methods for theoretical analysis and simulation. The advantages and problems are compared and analyzed. Considering the speediness, accuracy and stability of the algorithm, the multi-channel second-order generalized integrator frequency locking loop is applied to passive islanding detection for the first time. An island detection simulation model of single-phase photovoltaic grid-connected generation system is built. The experimental results show that the algorithm can extract amplitude and frequency accurately and quickly in passive islanding detection. Passive islanding detection can not solve the problem of blind spot detection under power matching. Active islanding detection is intended to break the power balance by adding disturbance. Then the occurrence of isolated islands is detected. Firstly, the active frequency shift method is analyzed theoretically and simulated, and its advantages and disadvantages are analyzed through the simulation results. On the basis of the above research. In this paper, a new islanding detection method, the intermittent frequency perturbation method, is proposed. The algorithm uses multi-channel SOGI-FLL to extract the voltage amplitude and frequency more accurately. A number of fixed Zhou Bo are used to give frequency disturbance to avoid the problem that zero crossing detection is easy to be interfered with. Intermittent disturbance improves the problem of large harmonic distortion caused by continuous disturbance. The reliability of islanding detection is further improved by adding amplitude disturbance, frequency and amplitude disturbance together. Simulation results verify the effectiveness of the algorithm. A photovoltaic array simulation experiment device based on programmable DC source is built. The accuracy and rapidity of the simulation effect are verified by open loop and closed loop experiments. At the same time, a small single-phase photovoltaic grid-connected power system hardware experimental system was built, completed the grid-connected experiment, which provides a hardware platform for the follow-up research of isolated island detection.
【学位授予单位】：中国石油大学(华东)
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM615

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