| The pantograph-catenary arc phenomenon has brought potential threat to the safe and reliable operation of high-speed trains.Under the realistic needs of railway speed increase,it is more urgent to study and detect pantograph-catenary arc.Revealing the internal parameters and unique characteristics of pantograph-catenary arc sound signal is expected to lay a data reference and theoretical foundation for studying arc damage mechanism,accurately identifying pantograph-catenary arc and improving pantograph-catenary service conditions.Researches on pantograph-catenary arc by scholars at home and abroad mainly focus on electrical,electromagnetic and spectral characteristics,which provides a basis for the detection of pantograph-catenary arc and has been applied in practice.But there are still some deficiencies in anti-jamming and reflecting pantograph-catenary arc strength in the existing research,and its cost is also high.With the rapid development of digital signal processing technology and wavelet analysis method,it has become a reality to analyze and diagnose pantograph-catenary arc acoustic signals.In this paper,the rapid development of high-speed railway in the world and the accompanying phenomenon of pantograph-catenary sliding electric contact arcing are introduced,and the importance of pantograph-catenary relationship is discussed.This paper summarizes the research progress of pantograph-catenary arc in electrical,electromagnetic radiation and arc detection by scholars at home and abroad,and points out the shortcomings of current research.This paper expounds the acquisition of sound accompanied by pantograph-catenary arc,introduces the experimental scheme of pantograph-catenary arc drawing on high-speed train and the required equipment to ensure that the sound,image,voltage and current data of arc can be collected.Quantitative analysis of several kinds of sound signals which may appear under pantograph and catenary working conditions is carried out.Based on the Fourier transform algorithm and windowing algorithm,the calculation and drawing of the acoustic spectrum and the processing of the power spectrum of the acoustic signal are carried out.The visual processing of the collected acoustic signal and the quantitative calculation of the frequency and relative energy value are realized.Based on sub-frame processing and short-term energy algorithm,the energy envelope characteristics of several kinds of sound signals are explored.The instantaneous power of pantograph-catenary arc is calculated and analyzed,and the relationship between electric energy of pantograph-catenary arc and acoustic signal energy is explored.Wavelet analysis toolbox is used in MATLAB software to decompose the arc acoustic signal through one-dimensional wavelet transform,and the characteristicsof its decomposition coefficients are explored.Then,three-layer wavelet packet decomposition based on Sym8 function is applied to several kinds of acoustic signals accompanied by pantograph and catenary operation,and the energy characteristics of each sub-band are quantitatively analyzed.Based on the analysis methods of acoustic spectrum,spectrum,short-term energy,wavelet decomposition,wavelet packet decomposition,wavelet packet energy and wavelet denoising technology,the unique characteristics of pantograph-catenary arc sound and other kinds of pantograph-catenary running accompanying sound are calculated.Acquisition of sound signals accompanied by pantograph-catenary arcing phenomenon in electrified train field operation is carried out,combined with the analysis of pantograph-catenary operation accompanied sound characteristics,based on the pantograph-catenary arc characteristic analysis method,the frequency,noise reduction,energy and wavelet packet decomposition analysis of signals are carried out respectively,and the analysis results are compared with the real arc situation in the field,and the connection between arc acoustic signals and pantograph-catenary are established. |
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