The Design Of Single-phase Smart Electric Meter Based On Real-time Measurement

With the rapid development of our country’s economy, energy consumptionis increasing year by year. According to the BP world energy statistics yearbook2014, China is the world’s largest energy consumption country, accounted for22.4%of global consumption and the49%of global net increase in2013.Wasting resources, unreasonable use of resources phenomenons isoutstanding, which result in environmental pollution problems. These problemsget increasingly the attention of society. Electricity is one of the major energyand the important guarantee for people’s living and national economy in ourcountry. Therefore, energy saving, efficient use of electricity have positive effecton solution of the problem of environmental pollution.Based on the above background, the smart electric meters as a bridge ofclients and power grid, not only requires high accuracy in terms of energymetering to achieve the purpose of fair dealing each other, but also cooperatestime-sharing electricity price policy, to change the mode of using power, so as toachieve the goal of efficient utilization. The design of single phase smart powermeter adopts the dedicated electric energy metering chip RN8209and main controller STM32cooperating related peripheral circuit design. It not onlyimproves the measuring accuracy, but also has more perfect functions whichinclude both-way communication by RS485interface, remote centralized meterreading, time-sharing electricity rate, supervisory and control for distributionnetwork and data storage, compared with the traditional electronic meters. Thearticle mainly includes the following several aspects work:1. The overall design of intelligent electric meter. Through functionalanalysis, the smart meter’s structure analysis and the system operationmechanism have been carried on, and the structure diagram of smart electricmeter has been designed. The main hardware module chip selection and detailedanalysis of the principle have been carried on.2. The design of smart electric meter hardware. Signal sampling principleelectrical and parameter calculation principle are analyzed in detail, thestudies of the internal structure of electric energy metering chip RN8209and itsworking mechanism have been finished. Signal attenuation filter circuit has beendesigned to turn the loaded line’s electrical parameters into metering chipacceptable input signal. According to the requirement of the smart meter’sfunction, the study has determined the main controller specific model and hascompleted its peripheral circuits which include storage module, power module,display module, communication module and JTAG interface circuit.3. The design of smart electric meter software. The study has used Clanguage to write the program of smart meter control system which mainly includes main program, measurement module subprogram, SPI communicationsubprogram, storage module subprogram and RS485both-way communicationsubprogram with KEIL software as experiment development platform. Theprograms have adopted modularized coding method with good readability andstrong portability. In the final, the system software anti-interference measureshave been analyzed.4. The smart electric meter module debugging and overall testing. Based onthe test platform built in the lab, the work has introduced the hardware circuittesting and software debugging process of the various functional modules. Inlaboratory, smart electric meter has been tested on several aspects such as activepower measurement, data display and storage, both-way communication testusing the existing electrical equipment as load. The experimental results showthat the single-phase smart electric meter can measure accurately and reliablyfamily active power consumption, and its measuring accuracy can reach0.5grade. Based on two-way communication function, it can achieve the expectedgoal such as remote centralized meter reading, online monitoring, historical datastorage.