Closed-loop feedback type all-fiber circuit transformer adopting polarization detection method

Abstract

The invention discloses a closed-loop feedback type all-fiber circuit transformer adopting a polarization detection method, and belongs to the technical field of optical current sensing measurement. The all-fiber circuit transformer solves the problems that the existing closed-loop feedback structure is complex and low in reliability or the existing polarization detection method is low in measurement precision, is easily disturbed by the outside and is difficult to meet the requirement of modern power systems for current measurement. An SLD (Super Luminous Diode) light source is connected with one end of a fiber coupler, the other end of the fiber coupler is connected with a fiber polarizer, the other end of the fiber polarizer is connected with a polarization-maintaining fiber delay line, the other end of the polarization-maintaining fiber delay line is connected with a N1-turn sensing fiber, the other end of the sensing fiber is connected with a reflector, a N2-turn feedback coil is wound on the N1-turn sensing fiber, two ends of the N2-turn feedback coil are respectively connected with an anode and a cathode of a feedback current source, and the control end of the feedback current source is connected with a signal processor; the lower half part of the fiber coupler is connected with a photo-detector, and the other end of the photo-detector is connected with a signal processor. The all-fiber circuit transformer has the advantages of simple structure, high reliability, little outside interference and high measurement precision.

Description

technical field [0001] The invention relates to an all-fiber-optic current transformer, in particular to a closed-loop feedback all-fiber-optic circuit transformer using a polarization detection method, and belongs to the technical field of optical current sensing and measurement. Background technique [0002] With the development of the smart grid, the voltage level of the grid is getting higher and higher. The traditional electromagnetic current transformer can no longer meet the requirements of the modern smart grid due to various disadvantages such as magnetic circuit saturation, poor dynamic performance, and unsatisfactory insulation safety. system construction needs. With the development of modern optical fiber technology and digital electronic technology, it has become an inevitable trend for all-fiber current transformers to replace traditional electromagnetic current transformers. [0003] The all-fiber-optic current transformer is a current transformer based on th...

AI Technical Summary

Problems solved by technology

The all-fiber-optic current transformer structure based on the principle of interference gyro adopts a symmetrical reciprocal optical path and a closed-loop feedback structure to make the measurement accuracy higher and the ability to resist external interference is stronger. High, especially the 1 / 4 wave plate necessary for the transmission system, 45° angle welding, and the phase modulator are easily affected by external factors such as temperature, resulting in errors in measurement results and long-term operation stability problems

Although the optical fiber current transformer using the polarization measurement method has a simple structure, fewer optical devices and high reliability, it does not have a closed-loop feedback structure and is not a symmetrical reciprocal optical path, so the measurement accuracy is low and it is difficult to resist external interference. weak ability

[0004] In summary, the existing all-fiber-optic current transformers either have long-term operation stability or temperature stability, and it is difficult to meet the current measurement requirements of modern power systems.

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