On-line fault location system for overhead power transmission lines using passive quasi-distributed fibre optic sensing

The design of an on-line fault location system for overhead high voltage transmission lines is described, The system utilizes a novel polarimetric fiber optic current sensing configuration based on the Faraday rotation effect. The fibre-optic sensor detects the current (and its location) induced in the ground wire in the event of a fault. The proposed sensor incorporates a long conventional transmission fiber without compromising the accuracy of measurement as a result of sensitivity to linear birefringence. Its sensing part is all-fiber and is free of polarization sensitive components. The sensing is quasi-distributed, which avoids the necessity for a separate power supply. Thus, the proposed configuration is especially suitable for remote fault location