The Research Of The Improved Hilbert-huang Transform Method And Power Quality Monitoring Device

With the development of society, impact, nonlinear load increasing quickly，power quality problems have become increasingly prominent. To solve these problems,first we must be able to monitoring and analysis the power quality parameters in realtime and accurate. To solve power quality problems, you first need to power qualityparameters in real time, accurate monitoring and analysis, provide the basis for theassessment of power quality and the effective remedial measures of power qualityproblems. Traditional power quality monitoring device has single function, high costlimitation, but the virtual instrument has feature-rich, cost-effective, high integrationand strong scalability characteristic, it provides an effective way to solve theseproblems.This article first described the basic concepts of power quality and itsdisturbance classification, discussed the research status at home and abroad of thepower quality analysis method, monitoring device and its standard, introduced thevirtual instrument technology and its characteristics, summarized the virtualinstrument relative superiority of the traditional instrument. By discussingof these key indicators such as the deviation of supply voltage, power systemfrequency deviation, three-phase unbalance, harmonic and voltage fluctuation andflicker, and analysis the characteristics of these parameters from theory intensively,laid the foundation for the detection of power quality indicators in this article.Focused on studing the traditional Hilbert-Huang transform method, in the light of itsexisting endpoint, local mean solving problem, take effective improved measures,using polynomial fitting algorithm, solved the problem of endpoint problemeffectively, using improved extremum field mean mode decomposition, solved thelocal mean of problem; at the same time, using the fractional Hilbert transformextracted the IMF components of the processing, calculated the instantaneousfrequency and voltage amplitude; through the results of numerical examples show that,the improved HHT transform method, expand the range of application of HHT,improved HHT detection accuracy. Then take the bus data acquisition card which isbased on PCI as the core, completed the power quality monitoring system hardwaredesign. With the help of LabVIEW platform to design the power quality parameters ofthe function module above and data analysis, processing, storage module and report generating module, completed the design of software system.Power quality monitoring system based on virtual instrument technology wasdesigned in this article, the monitoring interface is friendly and intuitive, and itpossessed the display functions of real-time waveform and of parameters index, and italso possessed the functions of data storage and analysis, report generation, over limitalarm, remote monitoring and Web access and so on.Through the simulation test, power quality monitoring system based on virtualinstrument technology was designed in this article, has high precision measurement,can monitoring of the power quality parameters well, satisfy the measurementrequirements, there is good prospect of application.