Multivariate analysis for investigation of outdoor insulator conditions

The works reported in this paper deals with experimental study on a porcelain outdoor insulator, which has been installed at a coastal switchyard, during eight months. The measurements were also carried-out on new-clean one, in order to have a comparison with the polluted one. The insulators have been subjected under high voltage, and were measured the leakage currents, in a hermetically sealed chamber, wherein the temperature, humidity and pressure could be controlled, for simulating the environmental condition of site. The leakage currents were analyzed with FFT method, and correlation coefficient and PCA of multivariate statistical tools. The correlation coefficient shows that the humidity influenced the leakage current magnitude, phase angle and the third harmonics as 56%, -88% and 59%, respectively, on the new-clean one. In case of polluted one, the humidity influenced the leakage current magnitude, phase angle and third harmonics as 60%, -68% and 53% respectively.