The quality of lead sealings of cable terminal has a direct impact on safe and stable operation of high-voltage cables,so it is necessary to carry out the pulse eddy current non-destructive testing to avoid the defects.But the eddy current detection signals can be impacted by noise in actual engineering,and wavelet denoising is an effective measure to filter out the white noise.However,the previous researches on wavelet denoising have typically selected wavelet parameters based on experiences,ignoring the impact of parameter variations on actual denoising effect.Hence,a wavelet denoising parameter selection method for eddy current detection signals is proposed based on particle swarm optimization algorithm,which adopts an evaluation index called normalized correlation coefficient(NCC)as fitness function.Through quantifying distortion degree of denoising eddy current detection signals near the peak,the optimal wavelet denoising parameters are obtained,that is,Sym25 wavelet,ten-layer decomposition layer and median threshold function,which makes the relative error between peak value of eddy current detection signals after denoising and peak time be less than 3%.The research results can provide a method reference for automatically determining the optimal wavelet denoising parameters for eddy current detection signals under different noise interference.
cable terminationlead sealingeddy current detectionwavelet denoisingparticle swarm optimization algorithm
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