An open-loop signal detection method and device for an all-fiber-optic current transformer

Abstract

The invention discloses an all-fiber current transformer open loop signal detection method which comprises the following steps: employing an asymmetric square wave with a period of 2t and an amplitude of Vpi / 2 as a modulation signal, carrying out phase modulation on an optical signal, wherein the t is a transit time of the all-fiber current transformer; after the optical signal after phase modulation is subjected to interference, converting the optical signal into an electric signal; subjecting the electric signal to a sampling treatment; in a period 2t, calculating difference between sampling sum of electric signal positive half cycle and sampling sum of electric signal negative half cycle, defining a difference result as S1, defining sampling sum of the electric signal as S2, dividing S1 by S2, and defining a divide resultant as an open loop signal detection result of the all-fiber current transformer. An embodiment of the invention also discloses an all-fiber current transformer open loop detection apparatus. Since the asymmetric square wave is employed as a modulation signal, in a demodulation process, factors related to light source power and circuit gain in an interference output result are eliminated through a specific algorithm, thus the open loop signal detection result is only related to Faraday phase shift, and accuracy of a measuring result is raised.

Description

Technical field [0001] The invention relates to the field of optoelectronics technology, and in particular to an open-loop signal detection method and device for an all-fiber current transformer. Background technique [0002] The all-fiber current transformer is a new type of current sensing device based on the Faraday effect and using optical fibers as sensitive and conductive components. The structure of the all-optical current transformer is as figure 1 As shown, the working principle is as follows: the light emitted by the light source is polarized by the fiber polarizer into linearly polarized light after passing through the circulator; the pigtail of the above-mentioned light polarizer and the pigtail of the phase modulator are welded at 45°, linearly polarized light The polarization-maintaining fiber injected into the fiber polarizer at 45° is decomposed into two linearly polarized beams of orthogonal mode, which are respectively transmitted along the X-axis and Y-axis of ...

AI Technical Summary

Problems solved by technology

The fluctuation of light output power of the light source and the drift of the gain of the signal detection circuit will cause the transformation ratio error, thereby reducing the measurement accuracy of the all-fiber current transformer

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