| With the development of society and improvement of industrial level, lots ofnon-linear loads have got widely used. On the one hand, they have greatly enhancedthe industry’s productivity, on the other hand，they have done great harm to the powerquality of the electric system. Voltage fluctuation and flicker discussed in this thesisis an important indicator to evaluate power quality. Various countries worldwide havepaid more and more attention to research and application of measurement methods forvoltage flicker parameters. Therefore, voltage flicker should to be detected andanalyzed in order to propose specific programs to manage flicker.Firstly, this thesis briefly introduces the basic concepts, research backgroundand evaluating indicators of voltage fluctuation and flicker, and then the source andinfluence of flicker are analyzed; the principle, characteristics and application scopeof the existing detection methods of voltage fluctuation are discussed and compareddeeply, as well as their application conditions and deficiencies; based on the basis offlicker measurement block diagram recommended by IEC, FFT-based flicker valuecalculation method is established by following IEC measurement principle andsimplifying flicker computation processing, the calculative amount of this method isreduced greatly, and the computation speed is improved obviously. In view of thepresence of Spectral leakage and picket fence effect in FFT method, Blackmanwindow interpolation FFT algorithm is proposed, and the simulation results show thatthe method has a reliable accuracy.Secondly, simulation results verify the feasibility and accuracy of this method,based on this theoretical basis mentioned and the powerful computing capabilities ofthe DSP chip, DSP-based voltage flicker detection system is designed. Hardware andsoftware design methods of function modules which are signal conditioning, dataacquisition, DSP signal processing and communication interface are presented indetail.Moreover, the voltage flicker detection system is tested based on research project,the flicker measurement data and test instance are given. Meanwhile, voltage flickerhave been measured respectively under same condition by the system designed and3196Power Quality Analyzer made in Japan. Measurement results and error analysisshow that the voltage flicker detection system is convenient to operate and reliable to measure with a high reference value for design of embedded digital flicker detectiondevice.Lastly, a summary of the research work is given in the end of this thesis. |
