Inapplicability Analysis Of IEC Flicker Meter And Research On Dynamic Flicker Parameters Detection Technology

With the goal of "carbon neutrality and emission peak" being proposed,a large number of new equipment are used in the power grid,resulting in a variety of new power quality problems,such as ultra-high harmonics,dynamic harmonics,intensive interharmonics,complex disturbances,oscillations and so on.Voltage fluctuations show irregular and dynamic characteristics,which lead to a variety of dynamic voltage flicker phenomena.The applicability of the IEC flicker meter standard in the new power system needs to be further analyzed.Therefore,it is urgent to analyze the inapplicability of the IEC flicker meter and explore the accurate dynamic flicker parameter detection method.The research background and significance of dynamic flicker are introduced firstly in this thesis,the causes of various flicker types are expounded,the research status of steady-state,dynamic flicker parameter detection methods are analyzed,and the research status of the IEC flicker meter is combed.According to the application of IEC flicker meter principle in new type of power system,the possible restrictions of IEC flicker parameters testing and the flicker value calculation is discussed respectively from four aspects:inapplicability of IEC flicker to interharmonic flicker,inapplicability of detection under different lamps,the inapplicability of the IEC flicker value standards,and the inapplicability of IEC flicker standard to rapid voltage change.Aiming at the difficulty of dynamic amplitude modulation flicker parameter detection,the adaptive variational modal decomposition(AVMD)improved new central difference analytic energy operator(NCD AEO)for dynamic amplitude modulation flicker parameter detection method is proposed.Hilbert change is used to extract the dynamic flicker signal envelope.The principle of the variational modal method is studied,and the relation between the energy of the reconstructed signal and the energy of the original signal is proposed to determine the number of mode decomposition adaptively.Then the envelope of dynamic amplitude modulation flicker signal is decomposed into multiple sub-model components containing only a single frequency.By the research of the analytic operator energy principle,the improved central difference method by the Taylor series is constructed to replace the backward difference method to obtain the first derivative of discrete data.The calculation formula of frequency and amplitude parameters of each envelope sub-mode is deduced,and the instantaneous frequency,instantaneous amplitude information,and time-domain information of dynamic amplitude modulation flicker signal are obtained.Through the simulation experiments on the conditions that single frequency dynamic amplitude modulation flicker parameter detection,multi-frequency dynamic amplitude modulation flicker parameters detection,the superposition of harmonic/interharmonic interference,the fundamental frequency offset,and noise interference,the results of simulation experiments and comparison of existing methods show that the proposed method not only can accurately extract a variety of dynamic parameters of flicker,can also reflect the time-frequency characteristics of the dynamic flicker signal.It has a strong anti-interference ability and can realize accurate detection of dynamic amplitude modulation flicker parameters.Aiming at the difficulty of dynamic interharmonic flicker parameter detection,an adaptive fast Total Least Squares-Estimation of Signal Parameters via Rotational Invariance Technique(TLS-ESPRIT)improved all-phase FFT sliding window is proposed for dynamic interharmonic flicker parameters detection.The signal is transferred from the time domain to the Meyer scale by using the MFCC to obtain the moment of signal mutation,and the size of the sliding window is determined accordingly.The input signal is divided into several approximately stationary data segments,and the Hankel matrix of each data segment is constructed.The relationship between the adjacent growth ratio of singular values and the number of frequencies is explored to build adaptive TLS-ESPRIT and simplify its calculation process.The adaptive fast TLS-ESPRIT is constructed to calculate the frequency of interharmonic to deduce the flicker frequency.The relationship between the peak line position and the frequency deviation is analyzed by apFFT spectrum,and the dynamic interharmonic amplitude and phase parameters are obtained to deduce the fluctuation parameters of the root mean square value of the flicker voltage and the peak voltage fluctuation parameters.Based on a variety of simulation analyses of dynamic interharmonic flicker signals and simulation experiments of the superposition of harmonic interference,the fundamental frequency offset interference and noise interference,the result of simulation experiments and comparison of existing methods show that the proposed method has high parameter detection precision,and well anti-interference ability.The accurate measurement of dynamic interharmonic flicker parameters is realized.Finally,a dynamic flicker parameter detection system is constructed based on the proposed algorithm.The functions of signal acquisition,amplitude modulated flicker parameter detection,interharmonic flicker parameter detection and data storage are realized based on PXI and Lab VIEW devices.The feasibility of the proposed algorithm and the accuracy of parameter detection are verified by the construction platform.