基于DSP的FTU核心模块的研制

【作者】 刘毅；

【导师】 孙同景；

【作者基本信息】 山东大学 ， 控制理论与控制工程， 2005， 硕士

【摘要】 随着国民经济的迅速发展和改革开放的深入,电力工业也在迅速发展,人们对电力的需求也在日益增长,同时对供电的可靠性以及供电质量的要求也越来越高,而配电网中应用的馈线自动化(Feeder Automation FA)技术,是提高供电可靠性的直接有效的技术手段,这也是配电网自动化的基础。加强这一领域的研究工作,必将极大的提高我国供电可靠性及电能质量。 馈线自动化现场终端装置(FTU—Feeder Terminal Unit)是FAS的核心单元,其主要功能就是信息采集、处理和转换以及与主站的通信。本文主要研究城乡10KV低压电网馈线自动化系统中FTU的实现。即对电网信息进行采集,转换,分析、处理以及进行算法设计实现和硬件的设计。 在算法研究方面,本文主要分析了目前在电网谐波处理方面比较常用的快速傅立叶(FFT)算法,通过FFT计算可以得到电网中直流分量和交流分量各次谐波的幅值和相角,同时可以得到电压、电流有效值、有功功率、无功功率等参数,从而对电网的运行品质进行评价。同时还介绍了采样点数的选择与频率分辨率之间的关系,并采取了周波采样64点。另外,本文还分析了目前电网上智能重合器的故障判断并迅速进行隔离的工作原理,并根据矩阵原理,给出了相应的算法,可以根据FTU上的检测信息准确判断出故障所在区域,并作出相应处理。 硬件方面,本文介绍了作者在课题研究中研制的FTU核心处理板,CPU采用了TI公司的高性能32位浮点DSP,保证处理速度能满足要求;AD器件采用了AD7865,能够4路同时进行交流采样的14位AD芯片,这样可以消除各相电压和电流由于非同步测量而带来的相位差;采用了一片CPLD芯片,来协调各个部件之间的工作;采用测频电路,可以实时监控电网的频率,从而实时的改变采样时间间隔,使得整个采样过程总是满足正弦信号的采样原则,最大限度的减少由于信号频域泄漏而引起的采样误差。 本文的研究和试验结果表明,本课题所研制的FTU的信息采集系统运算速度快,能够实时处理采样数据,并进行谐波分析,实时性好。并可以通过扩展的RS232通信口或者RS485通信口,跟主站进行通信以实现资源共享。更多还原

【Abstract】 With the rapid development of the national economy and the innovation opening, electric power industry developped rapidly. The electic demand of people increases. At the same time, we want the power supply more and more reliable and high quality. Feeder Automation used in the distributed network is a very efficiency measure and also the foundation of Distributed Autimation. So the research in this area can make our power supply reliable and quality.The FTU is the core unit of the FAS whose functions are mainly signal sampling, transforming and processing the information and communication with host. In this paper, the FAS of the city 10kV low voltage power networks are mainly researched.On the side of algorithm research, this paper mainly analyzes the FFT algorithm used in the power supply harmonious-wave analysis. By using FFT, we can get the diffirent magnitudes and phases of the DC (direct current) part and AC (alternating current) part in the power supply networks. We can also get the imaginary part and the real part of the current and voltage, and then we can get the awattful power and the wattless power and also power factor. This paper also introduces the connection between the number of sampling points and the degree of frequency differentiate, in this paper we take 64 sampling point in one cycle. In addition, this paper analyse the theory of fault judgement and insulation. It is based on the matrix theory. The corresponding algorithm gave that can estimate where the fault is and take the right disposal according to the information from FTU.On the side of hardware, this paper introduces the core board of FTU that is developed in the project research. It take the high performance, 32-bit DSP from TI company as its CPU and this DSPs can match the processing speed. It take the AD7865 as its AD part. This AD chip is 14-bit high performance and has four simultaneously AC sampled inputs which is adopted to avoid the sampling phase errors. The whole circuit is greatly simplified by using a piece of CPLD chip that take place of the complex decoding circuit. Also in this paper there put forward the method of computing bias of frequence which can simplify the correcting calculation ofharmonious coefficient.According to the result of the research and test, the FTU designed in this paper has the features of high calculating speed, strong real-time quality and strong data-processing ability. It can match the requirement of FTU. It is equipped with standard RS232 and RS485 interface which can communicate with the host of the system.更多还原