Four-quadrant-detector-based linear optical current sensor and detection method thereof

Abstract

The invention relates to a four-quadrant-detector-based linear optical current sensor and a detection method thereof. The linear optical current sensor comprises a laser source, a polarizer, a magneto-optical film, a beam expander, a radial polarization detection grating, a four-quadrant detector and a signal processing system that are arranged successively at one same optical path. In addition, the linear optical current sensor also includes a magnetic collection ring with air gaps; a to-be-detected current-carrying lead passes through the magnetic collection ring; and a magneto-optic thin film is arranged between the air gaps. In addition, the detection method includes: an optical signal passes through the polarizer, the magneto-optical film, the beam expander, and the radial polarization detection grating successively from the laser source and then a light spot is obtained; after the light spot passes through the four-quadrant detector, the optical signal is transformed into an electrical signal; the signal processing system collects the electrical signal and operation is carried out to obtain the size of a rotation angle, so that a to-be-detected current value in the to-be-detected current-carrying lead is obtained. Compared with the prior using the CCD camera, the sensor and the detection method enable the resolution ratio to be improved substantially, the accuracy to be enhanced, and the cost to be reduced.

Description

technical field [0001] The invention relates to a linear optical current sensor and a detection method realized based on a four-quadrant detector. Background technique [0002] Compared with the traditional electromagnetic current transformer, the optical current transformer has the advantages of simple insulation structure, no magnetic saturation, strong anti-electromagnetic interference ability, and wide measurement frequency bandwidth. It is a research hotspot for smart grid primary equipment. At present, most optical transformers use a linear array CCD (Charge Coupled Device) camera to locate the light spot to achieve current measurement, which overcomes many defects of the traditional light intensity detection mode, such as narrow dynamic measurement range, nonlinearity, optical power dependence, line Birefringence interference and temperature drift, etc., improve the practicability of the transformer. However, the spot image positioning method based on linear array CC...

AI Technical Summary

Problems solved by technology

However, the spot image positioning method based on linear array CCD has many shortcomings, such as high cost, large algorithm error, need to convert the rotation image into a translation image, and the measurement resolution is limited by the number of optical fibers of the image converter and the pixel size of the CCD camera. etc., especially when measuring small currents, the measurement error is large due to insufficient resolution, and it is difficult to meet the S-level requirements

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