Power Quality Detection Algorithm Research And The Realization Of The Monitoring Device

With the rapid development of national economy, due to operation of the largenumber of asymmetric rectifier equipment and nonlinear load, the harmonic, frequency,three-phase unbalance, voltage fluctuation and flicker, the power quality problem isbecoming more and more serious, at the same time power sector and power customers alsopay attention to the problem. On the one hand, the power quality problem is related to theoperation of the power system security and stability; On the other hand, the power qualityproblems will cause severe damage to precision instruments and result in unnecessaryeconomic losses to electrical equipmen. Therefore, real-time effective monitoring ofpower quality index has an important significance.Based on the power quality index study of national standard, combined withmeasuring way of domestic and foreign advanced power quality monitoring device, Idetermine the measuring method of this paper.The paper use the sampling seriesfrequency measuring method that can resistant to harmonic component interferencecorrection to measure frequency deviation.Above all provides theoretical basis for therealization of the power quality monitoring terminals.Research on power quality harmonic detection algorithm, and to explore the existingharmonic detection algorithm, especially for add window interpolation and add windowfrequency shift harmonic detection algorithm, and in MATLAB software to realize theabove two kinds of harmonic test, to a large number of simulation results are compared,and analyzed and concluded: add window frequency shift algorithm has higher accuracyin terms of harmonic detection, this article adopts the algorithm of harmonic detection. Onthis basis, combining with power direction method being the widely used in practicalengineering in the judgement of direction of harmonic, through constructing thesimulation circuit model, and calculate the power of public measurement point signal withadd window frequency shift and power direction method, checking the superiority andreliability of the proposed algorithm.On the basis of the above theoretical research,designing and realizing of powerquality monitoring terminal, the paper gives the design scheme of hardware and software implementation. Terminal hardware based on FPGA chip, the ARM chip and DSP chip,giving full consideration to the anti-interference design signal in the process of the designof the hardware, meeting the power quality monitoring terminal requirement of dataacquisition and processing, according to the hardware structure, software design usingmodular design, reasonable structure and convenient debug.