Research And Design On Smart Meter

With smart grid becoming a national trend of the power industry in future, smart meter which is the most important part of the infrastructure construction in smart grid, has become the research focus in meter industry. Smart meter is an intelligent based on microprocessor applications and network communication technology. It can meet the diverse needs of smart grid because of its multi-functional. Power quality problems caused by the nonlinear, asymmetric load in power system has made it is more important to study the function of power quality monitoring.Some algorithms related to power quality monitoring in smart meter are studied in this paper. First, frequency——the most important power quality parameter, traditional measurement algorithms error of which leads to spectral leakage, causing the low precision of harmonic measurement. An improved frequency measuring algorithm based on DFT (Discrete Fourier Transform) is proposed in this paper. It uses three sets of signal data which are separated by half a cycle to calculate two modified coefficients, which modify phase angle of two adjacent cycles. The frequency is measured by the phase angle change with good tracking results. On this basis,the algorithm achieve synchronous sampling by correcting the sample frequency real-timely so that can analysis harmonic accurately. Using wavelet transform and its multi-resolution analysis, accurate positioning of non-steady-state disturbance signals has been realized by the capability of wavelet to detect singular signal.This paper designs the hardware structure of smart meter and related software process. Hardware design is based on DSP chip and microcontroller. Power date is calculated by DSP so that can achieve power quality monitor and other related functions. The microcontroller is responsible for control, display, communication and other functions. Software design contains main program design, sampling procedures design and so on.