The Research On Monitoring Of Smart Grid Voltage Fluctuation And Flicker

With the development of smart grid,new energy including wind,solar and tidalenergy represent the energy development trend of smart grid.These new energy accessthe distribution network generally use the distributed power way. Thus it is easy tocause voltage fluctuation and flicker and other power quality problems.The voltagefluctuation and flicker as an important quality problem,will bring a lot of harms to ourlives and productions.So that we must carry on the effective monitoring.The voltagefluctuation and flicker monitoring includes two parts.One part is extract voltagefluctuation signal,the other part is analysis the voltage fluctuation signal.Thentcalculates the short time flicker value P_st and long time flicker value P_lt.According to the extract of voltage fluctuation signal,this thesis deeply analysisthe basic principle and implementation process of the wavelet fourier transformmethod for voltage fluctuation detection.The method combines the advantages ofwavelet transform and fast fourier transform.First it use wavelet transform toaccurately extract voltage fluctuation signal.Then it use fast fourier transform to getthe spectrum of fluctuation signal.So it can get the frequency and amplitude of themodulation wave.The MATLAB simulation result proves that this method is effective.According to the analysis of voltage fluctuation signal,this thesis detailedanalysis the basic principle and implementation technology of polynomial least squaremethod for voltage instantaneous flicker detection.Through curve fitting thesensitivity coefficient curve which appears in the process of calculation, get thepolynomial of curve fitting.Then it is easy to get the numerical that we need.Form theresults,the fitting precision can meet the requirements.Then the short time flickervalue is calculated by sorting statistical interpolation algorithm.Based on the new detection methods, this thesis designs a voltage fluctuation andflicker monitoring device.This thesis detailed describes the DSP+MCU circuitprinciple diagram of the device, and the software development and research based onLinux development environment.This device can not only real-time and accuratemonitor the voltage fluctuations and flicker parameters,but also monitor all kinds ofother power quality parameters.Its application prospect is broad.