Novel sensor system for leakage current detection on insulator strings of overhead transmission lines

We report the development of a measurement system capable of monitoring and characterizing the main features of the leakage current flowing on a polluted insulator string of a high-voltage transmission line. The system comprises a fiber-optic sensor, directly connected to one insulator of the string, that emits a sample of the leakage current waveform to a processing module via an optical link. A capacitive sensor connected to the processing module allows recording the relative humidity of the outer environment. At the present stage, six measurement units have been deployed on CHESF´s electrical transmission system in the Northeast of Brazil, and studies are underway to further correlate the degree of environmental pollution with humidity and leakage current activities on high-voltage insulator strings