Eddy Current Thermography for the Detection of Conductive Defects in Composite Insulators

Composite insulators are important and fundamental electrical equipment in power systems. However, the internal defects caused by long-term outdoor operation also cause great damage to the power system. For the purpose of eliminating the internal insulation breakdown which is caused by internal conductive defects of composite insulator, this work proposed a method for detecting internal conductive defects of composite insulator based on Eddy current thermography (ECT). This method uses the external excitation source to heat the conductive defects, internal defects can be detected through processing and analyzing the thermal image sequence captured by thermal camera. The effectiveness of this method is verified by analyzing original thermal image sequence. The detection effect of defects has been enhanced by using Principal component analysis (PCA) and independent component analysis (ICA) methods. The theoretical and experimental results indicate that Eddy current thermography has a broad application prospect in the detection testing of conductive flaws in composite insulators.