Digital optical fiber current sensor

Abstract

The invention relates to a digital optical fiber current sensor which is realized on the basis of the Faraday magnetooptical effect, the operating principle of an optical fiber gyro, the diffraction grating interference method and the digital image processing technology. A bundle of sensitive optical fibers is wound around a current-carrying conductor, left-handed polarized light and right-handed polarized light respectively pass through the sensitive optical fibers from both ends to generate a phase difference under the action of a current magnetic field, and the magnitude of the phase difference is a linear function of the conductor current. The diffraction grating interference method is used to enable the two polarized light beams to generate parallel interference stripes, the displacement distance of each stripe is a linear function of the phase difference between the two polarized light beams, namely the linear function of the conductor current, and the digital image processing method is used to measure the displacement distance of each stripe so as to obtain the real-time digital current signal. The measuring method provided by the invention is linear, thereby being applicable to alternating current or direct current (AC / DC) measurement in the power system.

Description

technical field [0001] The invention relates to a digital optical fiber current sensor, which is realized based on the Faraday magneto-optical effect, the working principle of the optical fiber gyroscope, a diffraction grating interference method and digital image processing technology. A bundle of sensitive optical fibers surrounds the current-carrying wire, and the left-handed polarized light and right-handed polarized light passing through the sensitive fiber from both ends generate a phase difference under the action of the current magnetic field, and the phase difference is a linear function of the wire current. The method of diffraction grating interference is used to make two beams of linearly polarized light produce parallel interference fringes. The moving distance of the fringes is a linear function of the phase difference, that is, the linear function of the wire current. The digital image processing method is used to measure the moving distance of the fringes to obt...

AI Technical Summary

Problems solved by technology

Its advantage is that the optical isolation between high and low potentials is realized by the transmission of optical signals; its disadvantage is that the method of light intensity measurement is nonlinear, and the measurement range and accuracy are limited, especially the effective measurement of harmonic components. , it is difficult to truly reflect the primary current of the system

In addition, electromagnetic, analog magneto-optical and electronic current sensors convert the primary analog signal into a secondary analog signal, and obtain digital signals by means of analog-to-digital conversion circuits, which have certain limitations in the application of digital substations.

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