Calibration System Of Capacitance Current Tester Of Distribution Network

In modern power systems,the distribution network subsystem directly provides electricity to users.Due to the increase of the electricity consumption and the number of cable lines,the capacitor current continues to increase,which affects the safety and stable operation of the distribution network.In order to ensure the stability of the power grid,it is necessary to measure the capacitance current and take corresponding measures to compensate.Although there are various types of capacitive current testers on the market,it can not guarantee the accuracy of capacitance current tester in a wide range of measuring range under various working conditions.Therefore,it is necessary to calibrate all kinds of capacitive current testers,and it is of great practical significance to develop a calibration device for capacitive current testers.In addition,with the development of intelligence and automation in the information age,Based on the research status of the calibration device,this paper designs a tester calibration device based on STM32 and Lab VIEW for various types of capacitive current testers on the market.The system can simulate various working conditions of the distribution network and a wide range of capacitance to ground.It can provide interfaces for various types of capacitance current testers for calibration,and provide a friendly manual operation platform that can support the storage and printing of calibration reports and the query of historical reports.Firstly,this paper studies the working principle of the capacitive current tester on the market at present.Combined with various working conditions of the distribution network,the function of the calibration device is determined through analysis.Combined with the functional requirements,the overall design scheme is discussed,and the cooperation mode of upper and lower computers is proposed.RS485 communication serial port and Modbus protocol are used to communicate between the upper and lower computers.Feasibility analysis was carried out from both the software and hardware aspects of the system,and the design plan was proposed.Secondly,the system designs the calibration device from the hardware module.According to the requirements of the device,the components are selected and the parameters are set.With STM32F427VIT6 minimum system as the core of the lower computer,the power module,peripheral circuit module,sampling module,relay drive module and communication network module are designed respectively.Thirdly,the system designs the calibration device from the software module.According to the needs of the device,the friendly operation interface is designed by using the functions of Lab VIEW graphical programming software,including user management,serial communication,system self-test,measurement system,data analysis and report processing functions.Finally,the software and hardware parts of the calibration device are debugged to verify the feasibility of the system.Then build a calibration system platform,and make a self-made distribution network capacitance current tester calibration system control cabinet.Simulate various working conditions of distribution network and different range of grounding capacitance to calibrate various interface testers,and analyze the calibration results.The experiment shows that the calibration device designed in this paper can calibrate the tester with high precision,and can meet the theoretical standards and working requirements.