Study And Design On Power Quality Online Monitoring System Based On ATT7022CU

Electrical energy is an important guarantee of the rapid development of nationaleconomy, the security and stability of the power quality has become an importantsection of power grid construction and management. With a great number of highcapacity load that is nonlinear and single-phase connected to the power grid, theproblems which were caused by those behaviors, like harmonic and three-phaseunbalance has been brought, it has been a potential risk of the security and stability ofpower grid. Therefore, how to monitor the power quality indexes effectively andreal-time has a great significance to the safe of power grid.In this paper, the work based on researching the standard and the algorithm of powerquality indexes, aimed at the core requirement of power quality monitoring, adopted thehardware solution which combined the front-end DSP monitoring unit with the MCUmain control circuit, to analyze power quality index through communication with theupper machine, the emphasis is mainly on discussing the problem which existed inanalysis of harmonic with traditional FFT in this part, and elaborated how to improvethe spectrum leakage by adding proper window function and barrier effect byinterpolation algorithm, obtained harmonic analysis result which had appended windowfunction and interpolation correction by MATLAB calculation.The construction of front-end monitoring unit adopted three-phase electric energymetering IC ATT7022CU with many advantages, like strong ability of data processing,high rate of sampling, excellent stability, etc. Through the function of automaticsoftware calibration, mainly included the active power gain calibration and phasecompensation, to achieve higher data accuracy. The main control circuit usedATMEGA128to establish, contained rich modules, like man-machine communicate,data storage, system clock, upper machine communication, environment analogacquisition, etc. those modules made the function of power quality monitoring systemfull-equipped and rich, finally obtained a good user experience.Finally, through building the experimental platform, monitoring each basic electricalparameter and power quality analysis by using upper machine software, it has provedthe design scheme in this paper is effective and has many advantages, such as, highprecision, good real-time capability, fully functional, etc.