Optical communication link for earth fault prediction of overhead lines

A description is presented of a continuous monitoring scheme for earth leakage currents on the suspension insulators of overhead lines. Local monitors at each tower will initiate a warning signal when the leakage current reaches a precalculated level. This signal will then be transmitted from that tower to the central station. An optical-fiber communication link is suggested for this purpose, and an appropriate identification system at the central station to locate the tower at which the warning signal is originated is outlined. The reliability of the link is discussed