A Sagnac Interferometric High-Current Optical Fiber Current Transformer Measurement Method Based on Non-reciprocal Phase-Shift Devices

Abstract

The invention relates to a design method of a Sagnac interference type high-current optical fiber current transformer based on a non-reciprocal phase-shifting device, and belongs to the technical field of electrical measurement. The technical solution is: (1) build a non-reciprocal phase shifter, use a circularly polarized optical fiber to make a current sensing head, fix a phase modulator on one end of the Sagnac delay coil, and introduce a non-reciprocal displacement bias; (2) Perform phase detection, demodulate the circuit with phase detection, and finally realize the phase demodulation method independent of light intensity; (3) use Faraday current sensing experiment to obtain the output waveform diagram and accuracy of the current; (4) through the electro-optic Voltages of different frequencies are applied to the crystal to control phase interference caused by slow variables such as temperature and light source intensity changes, and improve phase accuracy. The invention reduces the linear birefringence caused by the long delay coil, better maintains the system polarization, improves the system precision, reduces the modulation circuit and algorithm required by a set of phase bias devices, and improves the response time of the sensor.

Description

technical field [0001] The invention relates to a method for measuring a Sagnac interference type high-current optical fiber current transformer based on a non-reciprocal phase-shifting device, and belongs to the technical field of electrical measurement. Background technique [0002] Today, as people are stepping into the modern society, the power transmission capacity is increasing, and the transmission voltage is getting larger and larger. We need to face the problem of accurate measurement of large currents, the electrical insulation between instruments and the reliability requirements of signal transmission. May render traditional means of measurement powerless. For electric energy systems with high voltage, high current and high power, the current intensity measurement technology based on electromagnetic induction has exposed a series of shortcomings, such as poor insulation, high cost, heavy weight, large volume, magnetic saturation, and small dynamic range. , Narrow...

AI Technical Summary

Problems solved by technology

[0005] The optical fiber current sensor has a simple structure and low cost, but it is difficult to obtain the optical fiber that can maintain the circular polarization state for a long time, and the optical fiber current sensor with the optical fiber as the sensing head is difficult to operate as a commodity

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