Research On Communication Of Network-based Power Quality Monitoring System

In modern power system, the application of many types of non-linear electrical equipment has a very negative impact on the Power Quality which has attracted more and more attention of Power Engineering Technician. With the development of the power systems, the power grid is becoming more and more intellectualized. In the process of network-based monitoring equipment intellectualization, communication technology is playing an important role. Network-based monitoring equipment has high requirements for reliability and real-time of communication. According to the design of network-based power quality monitoring system function and hardware circuit, this paper formulates the relevant application layer protocol of CAN/DeviceNet, RS-485/ModbusRTU and Ethernet/ModbusTCP, studies the communication strategy and communication time deeply, designs the sofewares of the host and slave station, realizes the reliable and real-time communication function, satisfies the communication needs of network power quality monitoring system, and has important theoretical significance and practical value.Firstly, this paper designs the function of network-based power quality monitoring system on the basis of the analysis of current research at home and abroad in detail. In view of the above, every hardware module is designed, the main of this design are communication interface hardware and human-computer interaction interface hardware of slave station.In order to realize the three kinds of fieldbus communication protocol above, this paper firstly analyzes the three protocol standards and technical details, presents the method of realizing the corresponding protocol in the network-based power quality monitoring system, assigns service function codes, fomulates application-layer protocol correspondingly, and finally communication time is analyzed in theory.On the basis of designing the hardware and formulating the application layer communication protocol, to realize the communication function, embedded system development environment is established on RealView MDK platform. The C/OS-Ⅱembedded real-time operating system kernel is transplanted and the C/GUI graphical user interface is integrated. On these basis, the human-computer interaction function and communication function of the system is developed, and the specific program flow chart is also given.Finally, the software of the master station in the network-based power quality monitoring system has been designed and the joint commissioning of the communication function with the slave station has been carried out. It turned out that it's reliable and meet the requirement of real time nicely.This system has been put into operation at the present time. The communication function of the system turned out to be stable, reliable and effective.