Development Of Data Acquisition Device For Detection System Of Digital Relay Protection Tester

Relay protection tester is an important testing tool, it can ensure the safe and stable operation of power system, and it is possible for the protection devices for testing. With the use of digital and intelligent devices in substations, protection devices have gradually been digitized, it needs according to the new standards and requirements of digital protection devices for testing. Digital relay protection tester according DLT / 860 series of standards developed, it can effectively test the performance of digital protection devices, providing an important guarantee for the safe operation of power system. Therefore, it is necessary to develop digital relay tester detection system, which can be digital relay tester performance make regular checks.This design developed a device for data acquire, the data acquisition device is a core part of the detection system of digital relay protection tester. This device can collect data from the digital protection relay tester, and then process the data. It helps the detection system to test the main functions of the digital relay protection tester. The main modules of digital relay protection tester include AC small signal output module, FT3 frame output modules, and switch modules. Data acquisition device can acquire and process the data output from these modules and sends the data results to the host computer for analysis and display. The core of the design is STM32F407ZGT6 processor and CPLD. STM32F407ZGT6 processor uses Cortex-M4 core, and CPLD is a programmable logic device. Six-way exchange of small signal is amplified by the amplifier PGA205, and then use high-precision A / D sampling chip ADS8556 to acquire data, and through FFT operation to calculate the amplitude of the signal. FT3 frame using Manchester coding, and FT3 frame decoding performed by the CPLD. The decoded data is sent by STM32F407ZGT6 processor to the host computer for processing. Data acquisition device designed four pairs switch for detecting the switch module of digital relay protection tester. Data acquisition device communicate with the host computer via Ethernet.Firstly, this paper introduces the background and significance of the research, the main task of the data acquisition device needs to be done has been described. Then the algorithms and protocols that have been used in this design were introduced. In the hardware design part of this paper, the hardware modules have been analyzed with circuit diagram. In software design, the software ideas have been introduced with software flow chart. After that, let the data acquisition device for testing, and determine the performance of each module have achieved the requirements of this design. Finally, the results of this project are summarized, and points out the shortcomings and improvements.