Normality and Correlation Coefficient in Estimation of Insulators’ Spectral Signature

This work aims to classify the contamination state in insulators using statistical signal processing approaches. When subjected to high voltage, insulators can radiate radio frequency signals (corona effect). The histograms, normality, and correlation coefficient statistical methods are used to estimate the pollution state in glass insulators when subjected to 8 kV. It is shown that in particular situations the histograms can be used to distinguish clean and dirty insulators. The histogram limitation analysis can be improved using the correlation coefficient and the normality or Gaussianity test. Indeed, it is shown that using these parameters into an analysis per sub-bands, it is possible to estimate the pollution state of the insulators. That is, the analysis using these tools checks if the insulators spectra under test are noticeably different from the clean one, used as reference. It is achieved eliminating the fast variation of the correlation coefficient based on the amplitude and width of the peaks. The tests were done up to the frequency of 1 GHz using measured data.

[1]  A. G. Asuero,et al.  The Correlation Coefficient: An Overview , 2006 .

[2]  K. Iwai,et al.  Development of a new apparatus for contamination measurement of overhead transmission line insulators , 1998 .

[3]  Seung-Won Jung,et al.  Image Contrast Enhancement Using Color and Depth Histograms , 2014, IEEE Signal Processing Letters.

[4]  Lu Lu,et al.  Novel Robust Normality Measure for Sparse Data and its Application for Weak Signal Detection , 2013, IEEE Transactions on Wireless Communications.

[5]  Yuxiao Hu,et al.  Camera and microphone array for 3D audiovisual face data collection , 2008, 2008 IEEE International Conference on Acoustics, Speech and Signal Processing.

[6]  S. Shapiro,et al.  A Comparative Study of Various Tests for Normality , 1968 .

[7]  Ampol Tungkanawanich,et al.  Location of partial discharge source on distribution line by measuring emitted pulse-train electromagnetic waves , 2000, 2000 IEEE Power Engineering Society Winter Meeting. Conference Proceedings (Cat. No.00CH37077).

[8]  G. Clifford Carter,et al.  Estimation of source motion from time delay and time compression measurements , 1980 .

[9]  P.J. Moore,et al.  Remote diagnosis of overhead line insulation defects , 2004, IEEE Power Engineering Society General Meeting, 2004..

[10]  B.X. Du,et al.  Recurrent plot analysis of leakage current for monitoring outdoor insulator performance , 2009, IEEE Transactions on Dielectrics and Electrical Insulation.

[11]  G. Fontgalland,et al.  On the behavior of electromagnetic interference measured from glass insulator , 2004, 2004 10th International Symposium on Antenna Technology and Applied Electromagnetics and URSI Conference.

[12]  Jacob Cohen.  Statistical Power Analysis for the Behavioral Sciences , 1969, The SAGE Encyclopedia of Research Design.

[13]  M.D. Judd,et al.  Partial discharge monitoring of power transformers using UHF sensors. Part I: sensors and signal interpretation , 2005, IEEE Electrical Insulation Magazine.

[14]  P. Royston.  A Remark on Algorithm as 181: The W‐Test for Normality , 1995 .

[15]  R. Azzam,et al.  Optical monitor for contamination on HV insulator surfaces , 1997 .

[16]  Chengrong Li,et al.  Study of Corona Discharge Pattern on High Voltage Transmission Lines for Inspecting Faulty Porcelain Insulators , 2008, IEEE Transactions on Power Delivery.

[17]  Satoshi Nakamura,et al.  Hands-free speech recognition based on 3-D Viterbi search using a microphone array , 1998, Proceedings of the 1998 IEEE International Conference on Acoustics, Speech and Signal Processing, ICASSP '98 (Cat. No.98CH36181).

[18]  Caixin Sun,et al.  Stage pre-warning based on leakage current characteristics before contamination flashover of porcelain and glass insulators , 2009 .

[19]  P.J. Moore,et al.  Radiometric location of partial discharge sources on energized high-Voltage plant , 2005, IEEE Transactions on Power Delivery.

[20]  Satoshi Nakamura,et al.  Localization of multiple sound sources based on a CSP analysis with a microphone array , 2000, 2000 IEEE International Conference on Acoustics, Speech, and Signal Processing. Proceedings (Cat. No.00CH37100).

[21]  Richard Taylor.  Interpretation of the Correlation Coefficient: A Basic Review , 1990 .

[22]  J. Royston.  An Extension of Shapiro and Wilk's W Test for Normality to Large Samples , 1982 .

[23]  Liming Wang,et al.  Influence of sugar as a contaminant on outdoor insulation characteristics of insulators in a substation , 2012, IEEE Transactions on Dielectrics and Electrical Insulation.