【作者】 赵盼；

【导师】 郝迎吉；

【作者基本信息】 西安科技大学 ， 测试计量技术及仪器， 2011， 硕士

【摘要】 针对提高矿热炉工作效率与电网供电质量，研制了一种基于PLC的智能化大功率无功补偿监控系统。它以PLC为主机，自动完成数百个电容组无功补偿的监测与控制，通过现场触摸屏以及远程监测PC机在线修改投切参数，实时显示与存储电网的各个参数。本课题进行PC远程监测上位机、触摸屏现场控制上位机、PLC下位机、系统控制柜四个部分的设计。PC远程监测上位机以虚拟仪器LabWindows/CVI为开发平台，对电网的各个参数进行显示与存储，以及相应参数曲线的绘制，并能在线对控制参数进行修改以及实时监测电容的投与切。上下位机的数据通信使用RS485总线，并且遵循MODBUS协议，增强了监测仪在工业上的通用性。触摸屏现场控制上位机，通过RS232总线能够在控制现场完成实时显示电网参数、控制电容投/切以及修改控制参数等功能，方便了工程人员进行现场调试与控制。PLC下位机程序主要实现了与一次侧PDM以及三相二次侧智能电压表进行通信，采集变压器两侧的电网参数并将此参数通过串口上传给上位机进行分析与显示，与此同时接收上位机的控制信号，完成控制动作。在上位机损坏时，PLC独立工作，提高了系统的可靠性。系统控制柜方面设计了控制系统的仪表的排布方式以及系统的线路连接的方式，从硬件方面保证了系统的稳定运行。按上述方案设计，经过多次试验并已交付用户使用半年，结果表明该监控系统达到了设计要求，且运行稳定。更多还原

【Abstract】 In order to improve work efficiency of smelting electric furnace and the quality of powersupply, a kind of intelligent power monitoring and controlling system of reactive-powercompensationbased on PLC is developed. System, used PLC as the host, can complete themonitoring and controlling hundreds of capacitor of the reactive compensation automatically.Through the on-site touch-screen and the remote monitoring PC, it also can modify theswitching parameters online , real-time display and store each parameter of the grid.The subject is comprised of four designed parts，such as the remote monitoring PC ,on-site touch-screen , PLC and the system control cabinet.The remote monitoring PC, used virtual instrument named LabWindows/CVI asdevelopment platform, can display and store each parameter of the grid, draw the curves ofthe corresponding ones, modify the switching parameters, and monitor the capacitance whichis connected or cut. Upper and Lower data communication is using RS485 bus, and followingthe MODBUS protocol, which enhances the monitor’s versatility in the industry.Touch-screen, which is used controlling on-site through the RS232 bus, can completethese functions, such as real-time display each parameter of the grid, connect or cut thecapacitance, and modify the switching parameters. It facilitates the engineering staff on-sitedebugging and controlling the system.The main achievement of lower computer program of PLC is communicating with PDMin transformer primary side and three voltmeters in transformer secondary side, collectingeach parameter of the both sides of the transformer, and uploading these parameters to thehost computer via the serial port for analysis and display. At the same time, it also receives thecontrol signal from the host computer to complete the action of connecting or cutting thecapacitance. When the host computer is damaged, PLC can work independently, which is improving the reliability of the system.The design of system control cabinet contains two aspects, which is the pattern ofinstruments’arrangement and the way of system’s line connection. It is from hardware toensure the stable operation of the system.According to the above designs, after many trials and delivered to users for six months,the results show that the monitoring and controlling system meets the design requirements,and operates stably.更多还原