Design For Distributed Electricenergy Metering And Detection System Of The Digital Signal Source

In the rapid development of society today,electrical energy in economic construction,people's lives and other fields play an increasingly important position.The measurement technology of electrical energy is directly related to the economic interests of many parties,and its importance is self-evident.Therefore,the electrical energy metering system needs to be tested regularly.With the development of smart power grids,digital substation is the trend of today's electrical power system.The system of voltage merging unit,current merging unit and digital electrical energy meter is distributed structure.The traditional measurement method is not qualified for distributed electrical energy measurement.Therefore,it is of great significance to carry out distributed electrical energy metering system.In this paper,a set of digital signal source based on GPS synchronous distributed electrical energy metering system is designed and developed.The digital signal source includes two modules: signal acquisition module and signal sending module.The signal transmission module is subdivided into IEC61850-9-2 protocol The transmission sub-module of the data frame and the transmission sub-module of the FT3 data frame.The signal acquisition module uses a high-precision 16-bit ADS8568 chip to sample,through the FFT algorithm to calculate the amplitude,frequency and phase data provided to the signal transmission module,in order to ensure the voltage and current sampling signal synchronization using GPS synchronous sampling technology,GPS seconds pulse for GPS synchronization of samples.Magnetic isolation technology to high-frequency digital and analog ground isolation,effectively avoiding the digital signal and analog signal interference between the errors,improve the sampling accuracy.IEC61850-9-2 protocol data frame to Cortex-M4 as the core processor,the A / D chip data collected by FFT to send to the signal transmission module,according to IEC61850-9-2 protocol package,sent over the network,Through the photoelectric conversion device to the digital electrical energy meter,can be used for digital electrical energy meter detection.FT3 data frame is in line with IEC60044-8 protocol data frame to Cortex-M4 and FPGA as the core processor,Cortex-M4 microprocessor A / D chip to collect the signal in accordance with IEC60044-8 protocol FT3 data frame format package,Sent to the FPGA to Manchester coding after the data frame in the form ofManchester code through the fiber transmitter to send,can be used as a simulation of the output of the electronic transformer as a unit of the input unit,the distributed electrical energy measurement detection system for testing.This paper first describes the background of the research and the main task of the design of the digital signal source.Secondly,the sampling method,the signal processing method,the related protocol and the algorithm used in the digital signal source are described.And then the design of the hardware part of the design of the hardware part of the circuit with the schematic diagram,the software part of the flow chart design.And then for the test results to its analysis and the emergence of the causes of errors and eliminate the way to explain.Finally,the design of the digital signal source to sum up and pointed out that the design of the shortcomings and improvements.