Intensity Modulated Fiber Optic Sensor: A Novel Grid Measurement Unit

This article presents a novel approach to physical-displacement-based power grid measuring via an intensity-modulated fiber-optic sensor (IMFOS). An IMFOS utilizes one fiber to transmit the intensity modulated light from its electro-optic controller to a fiber-optic probe. The power grid voltage and current can induce physical displacements in transducers via the piezoelectric effect and the Lorentz law, respectively, which then result in a distance change between the optical probe and the reflective surface of the transducers. In parallel, multiple fibers are used to collect the reflective light for electro-optic conversion. A National-Instruments-based characterization platform is set up for performance evaluation. The testing result demonstrates that the IMFOS is immune to the inherent dc and low-frequency saturation issues prevalent in conventional potential and current transformers. Finally, the IMFOS is implemented in a universal grid analyzer to illustrate its applicability for phasor estimation in actual power grids.