A Technique for the Condition Monitoring of Outdoor Polymeric Insulators made of Micro/nano Dielectric Weathershed Material

In polluted regions, to minimise the electrical power outages due to overhead insulator flashover, measurement of insulator leakage current is used as a technique to monitor the health of the insulators. This technique gives emphasis to a critical level of current and the initiation of preventive maintenance depending upon the critical value of the leakage current. In this paper the behavior of leakage current along the micro/nano boron nitride (BN) filled silicone rubber (SR) weathershed material for application in outdoor insulators under polluted environment is analyzed by conducting the Inclined Plane Test (test for tracking and erosion) as per the IEC 60587 standard procedure. It is seen that the leakage current measured in this study before and after the initiation of the degradation by the erosion process is the same and does not show an increasing trend. Thus, the degradation of the composite insulator cannot be detected by merely checking the increase in the value of leakage current to the critical value. This paper proposes another method to detect the degradation of the material by analyzing the Fast Fourier Transform (FFT) spectra of the leakage current. This method can be used to monitor composite polymeric outdoor insulator made of micro composite as well as nanocomposite.