The Research And Design Of Watt-hour Meter Based On IC MSP430 And Interoperability Protocol

Multi-function electronic watt-hour meter has been widely applied in the electric power department, and the growing demand for power measurement and management also promote the development of watt-hour meter technology. In this paper, a high accuracy, interoperable and with market competitiveness electronic multi-function watt-hour meter is researched and designed to meet the needs of the electric power sector for high-precision, multi-functional and interoperable watt-hour meter.In the beginning of this article the research background and significance is introduced, the development and direction of multi-function electronic energy meter was summarized. And then the basic principles of electronic watt-hour meter measurement is researched, the synchronous sampling algorithm principle applied in this paper is analyzed and the communication protocols with interoperability -IEC62056 is introduced.The design method of electronic watt-hour meter hardware and software is analyzed stressly in this paper. In hardware part, the overall scheme design and circuit design with functional needs is analyzed , and the circuit design of each unit is divided into measuring microcomputer (MCU) module, power supply unit, the single-chip modules of functional management, key and display unit, internal memory unit, communication unit and real time clock unit. After the circuit analysis and design, the realization of the watt-hour meter with reliable and stable hardware is consistent. In software part, the overall program method is designed and introduced and the measurement MCU and management MCU is divided into two part for design .In measurement MCU module, the automatic determined method of the acquisition current, the program method of data acquisition and processing is achieved, and the required electrical parameters and the electric energy data is obtained through the software synchronization algorithm. In management MCU module, the energy calculation method, the meter models in accordance with IEC62056 and maximum demand measurement ,multi-rate, keys and display are designed, and then the IEC62056 standard software protocol stack implementation is given. The software design method is in strict accordance with the modular design.Finaly, the errors and its impact and compensation of both the hardware and software model is analyzed; after the basic parameters and the main design specifications in accordance with the relevant national standards are given, such as watt-hour meter error indicator has been tested including active and Reactive power error, voltage influence, frequency influence, power consumption, the experiments show that the watt-hour meter meet the design requirements, then the communication protocol compliance test of watt-hour meter are described.The accuracy of this 3-phase multi-function electronic watt-hour meter can be to 0.5S and reactive power class 1.0. It has been proved in test and practice that this watt-hour meter has high accuracy, flexible function add and cut ,and it meet the requirement of interoperability in automatic meter reading system. It's fit in with the market demand of the watt-hour meter.