Digital optical fiber current sensor

Abstract

The invention relates to a digital optical fiber current sensor. The fundamental principle is that: based on a Faraday magnetic rotation effect, a polarization plane of linearly polarized light passing through a magneto-optical crystal can rotate under the action of the magnetic field of the current and the rotary angle is in direct proportion to the magnitude of the current. The polarization directions of an annular analyzer are distributed uniformly in a radial direction in a 180-degree annular region; the linearly polarized light consistent with a certain polarization direction on the annular analyzer can pass through the analyzer; the linearly polarized light vertical to the polarization direction cannot pass through the analyzer; and therefore, the intensity of the polarized light passing through the analyzer in a certain 90-degree region on the annular analyzer is decreased gradually from maximum to minimum, a light intensity distribution image is formed, the maximum or minimum light intensity position can be found through the analyzing process of a CMOS / CCD image sensor, the rotary angle of the polarized light is determined, and the real-time digital quantity of a current signal is acquired. A current measuring method is linear, so that the method is suitable for the measurement of alternating current and also can be suitable for the measurement of direct current.

Description

technical field [0001] The invention relates to a digital optical fiber current sensor. The basic principle is to rotate the polarization plane of linearly polarized light under the action of the current magnetic field based on the Faraday magnetic rotation effect, and to measure the rotation of the polarization plane by using a radial analyzer and a digital image processing method. Angle and get the digital current signal. It is suitable for AC and DC current measurement in power system. Background technique [0002] Current transformers or current sensors currently used in power systems are electromagnetic based on Faraday's electromagnetic induction principle and the analog magneto-optical type of magnetorotation effect and electronic type realized by Rogowski coils. [0003] The analog magneto-optical current sensor has a development history of more than 60 years. Its principle is based on the fact that the polarization plane of linearly polarized light rotates under th...

AI Technical Summary

Problems solved by technology

Its advantage is that the complete electrical 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 non-linear, which limits the range and accuracy of the measurement

In addition, the electromagnetic, analog magneto-optical and electronic current sensors convert the primary analog signal into a secondary analog signal, which requires the help of an analog-to-digital conversion circuit to obtain a digital signal. Today, when the power system is developing towards digitalization, the above several This kind of sensor has great limitations in the application of digital substation

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