Research On Hardness Detection Of Cable Sheath Aging Based On LIBS

As an important channel for transmitting signals and energy,the use of cables has gradually increased with the development of society,and the workload of cable aging detection has also increased.Laser-induced breakdown spectroscopy(LIBS)is a fast,remote,online inspection technique.If LIBS technology can be applied to cable aging inspection,it will bring convenience to cable aging inspection.In this paper,polyvinyl chloride cables are used as experimental samples to find a feasible cable aging hardness detection method based on LIBS technology.The specific research work is as follows:(1)When conducting LIBS cable hardness detection,the collected cable sample spectral data contains noise and baseline due to external environment and sample properties.In order to reduce the influence of noise and baseline,a moving window averaging method was used to reduce the noise in the spectrum,and the asymmetric least squares method was used to remove the baseline in the spectrum.(2)In order to explore the feasibility of applying LIBS technology to cable aging detection,a cable aging hardness detection method based on LIBS was proposed.The linear regression R~2 between the spectral intensity ratio of Ca II 370.603nm and Ca I422.672nm lines and sample hardness was 0.74382,and the errors of RMSEC,RMSEP,MAE,ARE,etc.were 5.57779HD,10.86126HD,4.66199HD and 0.10929,respectively.The linear regression R~2 between plasma excitation temperature and sample hardness was0.78212,and the errors of RMSEC,RMSEP,MAE,ARE,etc.were 5.34484HD,3.49533HD,4.93396HD and 0.10888,respectively.By comparing their linear regression analysis evaluation parameters,it was found that the linear relationship between plasma excitation temperature and sample hardness is more suitable as a method for cable aging hardness detection.(3)In response to the influence of self-absorption effect on the accuracy of polyvinyl chloride cable sheath aging hardness detection method,this study established a multiple self-absorption correction model.After two self-absorption corrections,the linear regression R~2 between ion spectral line atomic spectral line ratio and sample hardness was increased to 0.92728,and the errors of RMSEC,RMSEP,MAE,ARE,etc.were reduced to3.08784HD,4.35274HD,2.80082HD and 0.07525,respectively.The linear regression R~2between plasma excitation temperature and sample hardness was increased to 0.96518,and the errors of RMSEC,RMSEP,MAE,ARE,etc.were reduced to 2.13677HD,2.15267HD,1.7601HD and 0.03527,respectively.The results showed that the linear relationship between plasma excitation temperature and sample hardness after correction was better and more suitable for application in polyvinyl chloride cable aging hardness detection.In this paper,the feasibility of cable aging hardness detection using LIBS technology was explored,and a cable aging hardness detection method based on the spectral intensity ratio of calcium element ions and atomic lines,as well as the relationship between plasma excitation temperature and sample aging hardness,was established.By multiple self-absorption correction,the detection accuracy was improved,providing useful ideas for using LIBS technology for cable aging detection.