Design And Implementation Of Low-voltage Power Distribution Monitoring Terminal Based On Ethernet

With the rapid economic development, both in terms of industrial or civilian, the demand of users for electricity is increasing, the reliability of the power supply requirements is also increasing. At present, in lOkV or less, especially following under 400V low voltage distribution terminal equipment maintenance fields, China uses artificial routine inspection of the way that the distribution line problems often can not be found for the first time. In addition, with the construction of the national grid, the grid structure is increasingly large. It gives great inconvenience to maintenance personnel, which causes the failure of the investigation and of the location of the fault caused. This passive, inefficient maintenance mode has no longer met the trend of intelligent network and become part of a need for improvement.Based on the current status of the development of domestic distribution automation and future trends, as well as the shortcomings of the maintenance of low voltage distribution terminal, through the analysis of functional requirements of low-voltage distribution cabinet for remote monitoring, This paper designs a low-voltage distribution terminal intelligent monitoring terminal based on the embedded operating system Windows CE, which uses ARM 11-core embedded development board OK6410A as hardware platform. The terminal achieves high-precision measurement of important power qulity evaluations, such as voltage,current, active power, reactive power, power factor and frequency, enables two-way communication between distribution cabinet and the remote monitoring center which is controlled by DM9000AE in the Ethernet module: reports each analog of the real-time operation of the power distribution cabinet to the monitoring center, and the monitoring center can control opening and closing action of switches in the power distribution cabinet by ordering the microprocessor. Further, through the study of the NMEA-0183 protocol and PDU encoding,this paper designs GPS module for positioning and for time and GPRS module for sending fault information. When the distribution protection switch occurs switching action,the terminal can promptly notify maintenance personnel by the way of a short message with content of failure time, location measured by the GPS module and cause of failure through GPRS module. The analysis of experimental results shows that the power distribution monitoring terminal has achieved purposes of remote control, telesignalling and telemetry,effectively reduce the labor intensity of maintenance personnel, saving manpower and resources,has a good application value.The main contents include:Firstly, the importance of distribution automation is analyzed, and domestic and foreign distribution automation developments are compared, which has described problems in low-voltage distribution automation in our country and formulate the main work of this paper to solve these problems.Second, it introduces the levels of low-voltage power distribution monitoring system, the location and function of the system in which the specified monitoring terminal. By analyzing and comparing different programs of monitoring network communication, Ethernet protocols,embedded systems, and analog acquisition approach, combined with the specific needs of the project, the overall structure of low voltage power distribution monitoring terminal designed by this paper and the relationship of input and output between each module are determined.Then from the perspective of monitoring terminal hardware components, the function of each module to achieve the principles and methods of communication between them is introduced. On this basis, combined with the structural characteristics of Windows CE itself,this paper describes the process of monitoring terminal software function implementation,including drivers and applications design.Finally, the results of telemetry error are corrected, the monitoring terminal is combined in the actual work environment to test. Through the analysis of the test results,the effect of low-voltage power distribution monitoring terminal designed by this paper for achieving integrated management and control, as well as improving management level of equipment are described. At the same time, this paper points out the current unresolved issues of this monitoring terminal and the future research directions.