分布式发电并网系统的孤岛检测方法及其实验研究

发布时间：2018-08-19 06:55

【摘要】：由于化石能源的衰竭与日益严重的环境问题以及大电网自身存在的缺陷,越来越多的分布式发电设备接入电网系统。但是,分布式发电系统规模不断扩大,供电系统会因为大电网中断供电而造成一些严重的问题,如非计划孤岛运行。这种运行模式会对电力设备和工作人员造成巨大的危害,因此孤岛检测研究具有非常重要的意义。本文从孤岛检测的基本问题,常用孤岛检测方法的工作原理以及对其进行改进的方法展开较为深入的研究。精准、有效的检测和尽量不影响电能质量是孤岛检测方法良好性能的标准,本文在分析常用孤岛检测方法(远程孤岛检测法、被动检测法、主动检测法)的基础上,找到它们各自优缺点以及适用的情况。针对常用检测方法的不足,提出一种复合型正反馈孤岛检测方法。该方法在电压值和频率两个参数中加入不同的正反馈控制算法,避免单一参数检测而造成的检测失败。同时,该方法以电压d轴分量和频率的变化量为控制扰动量,降低了正反馈控制对正常电能质量的影响。该方法能够提高检测精度,又能降低对电能质量的影响。本文针对并网逆变器控制模型展开研究,本系统采用双环控制,设计了电压环和电流环PI调节器。在Matlab/Simulink环境中构建仿真模型,并通过仿真验证了所提出检测方法的有效性和合理性。本文最后使用三相并网逆变器作为检测系统的实验平台,对孤岛检测进行实验研究,并进行硬件以及软件设计。硬件设计包括LCL并网滤波器参数设计、直流侧滤波电容和功率开关管的选取、驱动电流、控制电路以及交流电压电流采样电路、过流保护电路等;软件设计为复合型正反馈检测算法的实现。通过对实验结果的分析,验证了参数选择的合理性以及所提检测方案的有效性。
[Abstract]:Due to the depletion of fossil energy and the increasingly serious environmental problems as well as the shortcomings of large power grid, more and more distributed generation equipment is connected to the power grid system. However, the scale of distributed generation system is increasing, and the power supply system will cause some serious problems due to the interruption of power supply in large power grid, such as unplanned islanding operation. This operation mode will cause great harm to power equipment and staff, so the study of islanding detection is of great significance. In this paper, the basic problems of islanding detection, the working principle of the commonly used islanding detection methods and the improved methods are studied deeply. Accurate, effective detection and as far as possible do not affect the quality of power are the good performance of islanding detection methods, based on the analysis of common islanding detection methods (remote islanding detection, passive detection, active detection), Find out their respective strengths and weaknesses as well as the applicable situation. A compound positive feedback islanding detection method is proposed to overcome the shortcomings of common detection methods. In this method, different positive feedback control algorithms are added to the voltage and frequency parameters to avoid the detection failure caused by single parameter detection. At the same time, the influence of positive feedback control on normal power quality is reduced by taking the variation of voltage d axis component and frequency as the control disturbance. This method can improve the detection accuracy and reduce the influence on power quality. In this paper, the control model of grid-connected inverter is studied. The voltage loop and current loop Pi regulator are designed. The simulation model is constructed in Matlab/Simulink environment, and the validity and rationality of the proposed detection method are verified by simulation. In the end of this paper, three-phase grid-connected inverter is used as the experimental platform of the detection system, the detection of isolated islands is studied experimentally, and the hardware and software are designed. The hardware design includes the parameter design of LCL grid-connected filter, the selection of DC side filter capacitance and power switch, driving current, control circuit, AC voltage and current sampling circuit, over-current protection circuit and so on. The software is designed for the realization of compound positive feedback detection algorithm. Through the analysis of the experimental results, the rationality of the parameter selection and the validity of the proposed detection scheme are verified.
【学位授予单位】：江苏大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM73

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