A Synchronous Remote Detection System For Grid Connection Based On PLC

Grid connection is a frequently performed operation in power systems.The conditions for quasi-synchronized grid connection in the grid connection are that the voltage difference,frequency difference and phase difference are all within a certain range.Because the distance between the substation and the power plant is long and distributed in different areas,it is particularly important to remotely detect the voltage difference,phase difference and frequency difference of the parameters of the grid-connected synchronization point of the substation.In this paper,a set of grid-connected synchronization remote detection system is designed.The remote substation collects the voltage difference,frequency difference,and phase difference parameters of the synchronization point through PLC(Programmable Logic Controller),and displays the quasi-synchronized grid-connected synchronization point parameters of the remote substation on the touch screen in real time.The main research contents are as follows:According to the requirements of a certain power grid,the overall scheme of the grid-connected synchronous remote detection system is designed,the overall framework that meets the requirements of the system is designed,and the hardware design,hardware schematic design and software design of the system are completed.The hardware design is designed according to the functions that a certain power grid needs to complete.The PLC1200 x of Siemens is used as the main controller of the system.The analog input module collects the parameters voltage difference,frequency difference and phase difference of the quasi-synchronized grid-connected synchronization point.Through Modbus /TCP communication protocol to obtain the data of the remote synchronization point,according to whether the system fails,the digital output module controls the indicator light and buzzer.The software design is to realize the hardware function and design the human-computer interaction interface,so that the parameters of the remote synchronization point and the exact location of the fault point can be displayed on the touch screen(KTP900 Mobile)in the most intuitive form.Finally,testing of the system is done in the laboratory.The system designed in this paper realizes the reliable transmission of remote substation data,and can detect the parameters of the remote quasi-synchronized grid-connected synchronization point in real time.