Voltage sensor based on optical fiber and the electro-optic effect for high voltage telemetry applications in industrial automation

A fiber optic sensor (FOS) for high voltage telemetry is proposed. FOS is constituted by 100 m of multimodal fiber coupled to a transducer element based on the electro-optic effect with a double pass configuration of the light wave through a Bi12TiO20 (BTO) fotorrefractive crystal. To guarantee the double pass, a back-reflective prism with high stability to environmental changes of temperature is incorporate to the transducer element. The double reflection of the light wave in the prism allows the BTO to work in a wide linear region of the transfer function. To prove the feasibility of this FOS, a periodic wave of AC and a transitory event, both of high voltages, applied to an aluminium tube were measured from a distance of 1 mt. It is demonstrated that the proposed sensor is robust, linear, and stable against the variations of temperature and of high sensibility for applications of high voltage telemetry.