Study On The Measurement Of Electric Power In Three-phase Intelligent Electric Meter

The three-phase smart meter is the main measurement tool for household electricity and industrial electricity,and is the main basis for power calculation.The accuracy of its measurement involves the interests of all parties.With the constant use of non-linear loads in modern life,the generated harmonics cause the continuous decline of power quality,such as the distortion of voltage and current.After unremitting research and analysis by experts,it can be known that a non-linear load will absorb part of the energy of the fundamental wave of the power grid and convert it into harmonics,and inject it into the power network.This not only reduces the power quality,but also affects the existing meter measurement.Accuracy.With the continuous in-depth reform of the electricity market,we have been working to more closely coordinate various aspects,such as grid systems,markets and users,to improve grid distribution efficiency and distribution automation,and improve power quality.Establishing smart meters with integrated,accurate and high-speed bi-directional communication is an urgent problem to be solved.Through theoretical analysis,it is found that the current energy metering scheme will lead to a decrease in the metering accuracy of the meter when harmonics are present.By analyzing the literature to analyze the causes of the defects in the current energy metering scheme,and improving the metering scheme,the fundamental signal components and harmonic components in the power signal are extracted and analyzed separately.Finally,based on the flow of harmonics,the Determine the user’s electricity bill.And using the advantages of windowed Fourier transform in analyzing steady-state signals,and the advantages of wavelet transform in detecting higher harmonics,a hybrid detection algorithm was designed to adapt the improved measurement scheme and improve harmonic detection.The accuracy of the analysis ultimately increases the metering accuracy of the meter.Considering that under the premise of realizing the function of the electric meter,should choose the chip with higher cost performance as its MCU.So choose STM32 series here as the main controller of the system to design,design the pre-sampling circuit,storage circuit and communication circuit and other hardware circuits.And designed a basic program,including: the main program design,data sampling and processing program design and communication program design.Can realize some basic functions of the smart meter,such as: energy metering,communication and other functions.Finally,an experimental platform was built to test and analyze the feasibility of the program.