分布式电能计量检测系统的数字信号源设计

发布时间：2018-01-28 08:28

本文关键词： 分布式电能计量检测数字信号源 GPS同步采样 Cortex-M4 FPGA　出处：《南昌航空大学》2017年硕士论文　论文类型：学位论文

【摘要】：在社会快速发展的今天,电能在经济建设、人民生活等各领域扮演着愈来愈重要的地位。电能的计量检测技术直接关系到多方的经济利益,其地位重要性不言而喻,因此电能计量检测系统需要定期进行检测。随着智能电网的发展,数字化变电站是当今电力系统趋势。其中电压合并单元、电流合并单元和数字电能表等系统呈分布式的结构,传统的传统的计量方式已无法胜任分布式电能的计量检测工作,因此开展分布式电能计量检测系统具有重大意义。本课题开发设计了一套基于GPS同步分布式电能计量检测系统的数字信号源,该数字信号源包括信号采集模块和信号发送模块两个模块,信号发送模块又细分为IEC61850-9-2协议数据帧的发送子模块和FT3数据帧的发送子模块两个部分。信号采集模块选用一个高精度的16位ADS8568芯片进行采样,通过FFT算法计算得到幅值、频率和相位等数据提供给信号发送模块,为保证电压、电流采样信号的同步采用GPS同步采样技术,利用GPS的秒脉冲对采样进行GPS同步。采用磁耦隔离技术将高频率的数字地和模拟地隔离开,有效地避免了数字信号与模拟信号间的干扰带来的误差,提高了采样精度。IEC61850-9-2协议数据帧的发送以Cortex-M4为核心处理器,将A/D芯片所采集的数据经过FFT计算后发送到信号发送模块,按照IEC61850-9-2协议打包,通过网络发送,经过光电转换装置传输到数字电能表,可用于数字电能表的检测。FT3数据帧是符合IEC60044-8协议的数据帧,以Cortex-M4和FPGA作为核心处理器,Cortex-M4微处理器将A/D芯片采集的信号按照IEC60044-8协议的FT3数据帧格式打包,发送到FPGA中做曼彻斯特编码后将数据帧以曼彻斯特码的形式通过光纤发射器发送,可用作模拟的电子式互感器的输出作为合并单元的输入,对分布式电能计量检测系统进行检测。本文首先对课题研究的背景意义和本次对设计的数字信号源的主要任务进行了说明。其次对数字信号源所采用的采样方法、信号处理方法、相关协议及算法进行了阐述。然后对本次设计的数字信号源的硬件部分的设计结合电路原理图,软件部分结合流程图的设计展开说明。接着针对测试结果对其进行分析并对出现的误差的产生原因和消除办法展开说明。最后对本次设计的数字信号源进行总结并指出几点本次设计中的不足之处和改进办法。
[Abstract]:With the rapid development of society, electric energy plays a more and more important role in many fields, such as economic construction, people's life, etc. The measurement and detection technology of electric energy is directly related to the economic interests of many parties. With the development of smart grid, digital substation is the trend of power system. The current combining unit and the digital watt-hour meter have distributed structure. The traditional metering method can not be used to measure and detect the distributed electric energy. Therefore, it is of great significance to develop a distributed power measurement and detection system. This paper develops and designs a digital signal source based on GPS synchronous distributed power measurement and detection system. The digital signal source includes two modules: signal acquisition module and signal transmitting module. The signal transmission module is subdivided into two parts: the IEC61850-9-2 protocol data frame sending sub-module and the FT3 data frame transmitting sub-module. The signal acquisition module selects a high precision 16-bit AD. S8568 chip is sampled. The data of amplitude, frequency and phase are obtained by FFT algorithm. In order to guarantee the voltage, the synchronous sampling technology of GPS is used to synchronize the current sampling signal. The sampling is synchronized with the second pulse of GPS, and the high frequency digital and analog isolation is separated by magnetic coupling isolation technology, which effectively avoids the error caused by the interference between digital signal and analog signal. Improve the sampling accuracy. IEC61850-9-2 protocol data frame transmission using Cortex-M4 as the core processor. The data collected by the Ar / D chip is sent to the signal sending module after the FFT calculation. It is packaged according to the IEC61850-9-2 protocol and sent through the network. The data frame of FT3, which can be used to detect the digital watt-hour meter, is the data frame in accordance with the IEC60044-8 protocol, which is transmitted to the digital watt-hour meter by the photoelectric conversion device. Use Cortex-M4 and FPGA as core processors. The Cortex-M4 microprocessor packages the signals collected by the Ar / D chip according to the FT3 data frame format of the IEC60044-8 protocol. The data frame is transmitted in the form of Manchester code to the FPGA by the fiber optic transmitter and can be used as the output of the analog electronic transformer as the input of the merging unit. In this paper, the background significance of the research and the main tasks of the designed digital signal source are explained. Secondly, the sampling method of the digital signal source is introduced. . Signal processing methods, related protocols and algorithms are described. Then the design of the hardware part of the digital signal source is combined with the circuit schematic diagram. The software part combines the design of flow chart to explain. Then it analyzes the test result and explains the cause of the error and the elimination method. Finally, the design of digital signal source is summarized. And points out several points in the design of the deficiencies and improvements.
【学位授予单位】：南昌航空大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM933.4

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