Fiber-optic sensor system for leakage current detection on insulator strings of overhead transmission lines

In this paper we report the development of an optical 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. At the present stage, six different systems have been deployed on CHESF's electrical distribution 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.