Optical voltage sensor
AssigneeABB Research Ltd.
InventorKlaus Bohnert
Life of this patent
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Abstract
A voltage sensor includes two optical sensing fibers and a control unit. The sensing fibers carry a first mode of light and a second mode of light, which are orthogonally polarized, with a birefringence between the two modes depending on the electric voltage to be measured. The control unit is configured to generate light for the two modes in the sensing element and to measure the phase delay suffered between the two modes. A 45° Faraday rotator is arranged between the control unit and the sensing fibers. The Faraday rotator allows the behavior and functionality of the sensing fibers and their associated components to be converted to those of a magneto-optical current sensors with polarization-rotated reflection, which in turn allows use of advanced measuring techniques developed for optical gyroscopes and current sensors.
Claims20
An optical voltage sensor comprising:
- at least one elongate optical sensing element configured to carry at least a first mode of light and a second mode of light, said modes having substantially orthogonal polarization with respect to each other, and a birefringence between said modes being dependent on an electric voltage to be measured;
- a control unit configured to generate light for said two modes in said sensing element and to measure a phase delay suffered by said two modes due to said birefringence;
- and
- at least one Faraday rotator arranged between said control unit and said sensing element, said at least one Faraday rotator being configured to rotate light by 45° for each pass therethrough.
Dependencies are inferred from the claim text.