In order to suppress the white noise interference in partial discharge(PD)detection and accurately extract the characteristics of local discharge pulse acoustic signal of transformer under strong noise environment,the...In order to suppress the white noise interference in partial discharge(PD)detection and accurately extract the characteristics of local discharge pulse acoustic signal of transformer under strong noise environment,the adaptive separation and denoising of the discharge pulse acoustic signal were analyzed under low signal-to-noise ratio(SNR)environment.Firstly,the optimal decomposition mode number K of the variational mode decomposition(VMD)was determined based on Spearman correlation coefficient,then the reliability of the proposed Spearman-variational mode decomposition(SVMD)method decomposition was verified by simulated signals,and finally the actual discharge pulse acoustic signal was decomposed and denoised based on the Spearman correlation coefficient averaging threshold method to extract the eigenmode function components of the discharge pulse signal.The results showed that SVMD adaptively solved the unknown defects of VMD mode number,and effectively extracted the modal components of complex signals,and successfully realized the denoising of transformer partial discharge acoustic signals.The proposed method effectively removed white noise interference in the partial discharge acoustic signal and obtained a smooth filtered signal.It retained the integrity of the partial discharge signal to the maximum extent and was beneficial to the subsequent research of partial discharge.The improvement of VMD was helpful to promote its wide use in industrial equipment condition inspection.展开更多
Based on the safety coefficient method,which assigns rock failure criteria to calculate the rock mass unit,the safety coefficient contour of surrounding rock is plotted to judge the distribution form of the fractured ...Based on the safety coefficient method,which assigns rock failure criteria to calculate the rock mass unit,the safety coefficient contour of surrounding rock is plotted to judge the distribution form of the fractured zone in the roadway.This will provide the basis numerical simulation to calculate the surrounding rock fractured zone in a roadway.Using the single factor and multi-factor orthogonal test method,the evolution law of roadway surrounding rock displacements,plastic zone and stress distribution under different conditions is studied.It reveals the roadway surrounding rock burst evolution process,and obtains five kinds of failure modes in deep soft rock roadway.Using the fuzzy mathematics clustering analysis method,the deep soft surrounding rock failure model in Zhujixi mine can be classified and patterns recognized.Compared to the identification results and the results detected by geological radar of surrounding rock loose circle,the reliability of the results of the pattern recognition is verified and lays the foundations for the support design of deep soft rock roadways.展开更多
基金supported by State Grid Gansu Electric Power Research Institute(No.52272219000Q).
文摘In order to suppress the white noise interference in partial discharge(PD)detection and accurately extract the characteristics of local discharge pulse acoustic signal of transformer under strong noise environment,the adaptive separation and denoising of the discharge pulse acoustic signal were analyzed under low signal-to-noise ratio(SNR)environment.Firstly,the optimal decomposition mode number K of the variational mode decomposition(VMD)was determined based on Spearman correlation coefficient,then the reliability of the proposed Spearman-variational mode decomposition(SVMD)method decomposition was verified by simulated signals,and finally the actual discharge pulse acoustic signal was decomposed and denoised based on the Spearman correlation coefficient averaging threshold method to extract the eigenmode function components of the discharge pulse signal.The results showed that SVMD adaptively solved the unknown defects of VMD mode number,and effectively extracted the modal components of complex signals,and successfully realized the denoising of transformer partial discharge acoustic signals.The proposed method effectively removed white noise interference in the partial discharge acoustic signal and obtained a smooth filtered signal.It retained the integrity of the partial discharge signal to the maximum extent and was beneficial to the subsequent research of partial discharge.The improvement of VMD was helpful to promote its wide use in industrial equipment condition inspection.
基金provided by the National Natural Science Foundation of China(Nos.51322401,51309222,51323004,51579239 and 51574223)the Opening Project Fund of Shandong Provincial Key Laboratory of Civil Engineering Disaster Prevention and Mitigation(No.CDPM2014KF03)+2 种基金the State Key Laboratory for GeoMechanics Opening Project Fund of Shandong Provincial Key Laboratory of Civil Engineering Disaster Prevention and MitigationDeep Underground Engineering,China University of Mining&Technology(No.SKLGDUEK1305)China Postdoctoral Science Foundation(Nos.2014M551700and 2013M531424)
文摘Based on the safety coefficient method,which assigns rock failure criteria to calculate the rock mass unit,the safety coefficient contour of surrounding rock is plotted to judge the distribution form of the fractured zone in the roadway.This will provide the basis numerical simulation to calculate the surrounding rock fractured zone in a roadway.Using the single factor and multi-factor orthogonal test method,the evolution law of roadway surrounding rock displacements,plastic zone and stress distribution under different conditions is studied.It reveals the roadway surrounding rock burst evolution process,and obtains five kinds of failure modes in deep soft rock roadway.Using the fuzzy mathematics clustering analysis method,the deep soft surrounding rock failure model in Zhujixi mine can be classified and patterns recognized.Compared to the identification results and the results detected by geological radar of surrounding rock loose circle,the reliability of the results of the pattern recognition is verified and lays the foundations for the support design of deep soft rock roadways.
