Design Of Intelligent Electric Meter With Harmonic Analysis Function

Power harmonic is an important cause of power grid pollution,and the existence of harmonics will affect the normal operation of power equipment,and even damage electrical equipment.However,the widely used power electronic equipment,motors,welding machines and other nonlinear devices have led to an increase in power harmonics.Grid harmonic monitoring is usually achieved by proprietary power quality monitoring equipment.Or by setting up an independent on-line inspection system for power quality.However,the cost of this system is higher,which greatly restricts the monitoring and control of harmonic problems.In this paper,an intelligent electric meter with harmonic analysis function is designed.It can be arranged on the client side like the electric energy meter,and can realize the analysis and monitoring of the power harmonic of the user.It can effectively reduce the cost of power harmonic monitoring.This paper first discusses the background and significance of the topic.It introduces the development of related fields at home and abroad,and analyzes some key technologies in the design of this subject.Through comparative analysis,it determines the use of GPRS communication transmission mode as the design of power information transmission mode.Secondly,it analyzes the overall design of harmonic meters.It discusses the realization of harmonic detection and the realization of smart meter.It combines the above two implementations,determines the overall structure of the design,and draws the structure diagram of the combination of energy metering and harmonic detection.It selected the STM32F103 controller as the controller of the design.It focuses on the design of the hardware unit of the system.It analyzes the basic circuit of the main controller design,data transmission circuit,harmonic detection and analysis of unit circuit design,voltage transformer acquisition circuit design,electric energy metering and anti stealing circuit and power supply circuit design.In the circuit design of harmonic detection unit,it compares the advantages and disadvantages of different ADC sampling schemes.In view of the functional requirements of the design,the ADS8564 chip is chosen as the ADC converter controller.In the electric energy metering unit,RN8209 D is selected as an electric energy measuring chip,and the chip can realize the function of detecting electricity stealing at the same time.In the design,it has analyzed each kind of device contrast type selection,has drawn the detailed electric circuit principle diagram.It analyzes the software system design of intelligent ammeter with harmonic detection function.According to the different function units,the software design is divided intorelatively independent subroutines.It discusses the harmonic detection subroutine,the electrical energy measurement and the anti power stealing detection subroutine and the communication unit subroutine design.It gives a detailed flow chart of the program.Finally,the function of the meter is tested.The accuracy of meter measurement and the accuracy of harmonic detection are mainly tested.By comparing with the standard meter and harmonic analysis,it is found that the accuracy of the meter can reach 2.It meets the basic requirements for civil electrical measurements.The accuracy of harmonic detection is less than 5% of that of PM3000 A harmonic analysis,and it meets the requirement of use.