Reflecting type full-optical fiber current sensor

A current sensor, all-fiber technology, applied in voltage/current isolation, measuring current/voltage, instruments, etc., can solve problems affecting the measurement accuracy of transformers, and achieve the effect of reducing polarization noise and improving measurement accuracy

Inactive Publication Date: 2008-12-31
SHANGHAI UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, since the 1/4 wave plate and the induction fiber coil are by no means ideal polarized light components, there is still a small amount of residual polarized light in the X direction when the polarized light in the X direction is converted into the polarized light in the Y direction and returned, and the polarized light in the Y direction is also conv

Method used

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  • Reflecting type full-optical fiber current sensor
  • Reflecting type full-optical fiber current sensor
  • Reflecting type full-optical fiber current sensor

Examples

Experimental program
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Effect test

Example Embodiment

[0024] Example 1: Refer to Figure 1. The structure and working principle of the reflective interferometric all-fiber current sensor are: light waves enter the polarization-maintaining fiber coupler 4 from the light source 1 after passing through the isolator 2, and its two forward output ends are respectively connection After the polarizers 5 and 6, the two lights are linearly polarized lights polarized in the x direction. Where x of the output of polarizer 5 The linearly polarized light in the direction of the light passes through the first quarter-wave plate 7 in the light wave phase bias system to become circularly polarized light. After passing through the Faraday rotator 8, the circularly polarized light is rotated by 45 degrees to circularly polarize the light. In terms of light, when the space is rotated by 45 degrees, there is a 45-degree phase difference in time. When it is reduced by the second quarter-wave plate 9 to linearly polarized light in the x direction, the line...

Example Embodiment

[0025] Embodiment 2: Referring to Figure 2, the reflective all-fiber current sensor is based on embodiment 1. The complementary signal output to the other port after interference by the polarization-maintaining fiber coupler 4 is transmitted by the second polarization-maintaining fiber coupler 3 Take out half for detection and signal processing, so that although the signal will be more than half, the input optical power will be lost by half.

Example Embodiment

[0026] Embodiment 3: Referring to Fig. 3, the reflective all-fiber current sensor is based on embodiment 2, changing the positions of the two polarizers 5 and 6, and the effect is the same as that of Fig. 2. The coupler 4 and the two polarizers 5 and 6 in Fig. 2 can also be replaced with planar optical waveguide Y-splitters. Since the planar optical waveguide itself has the function of a polarizer, its effect is the same.

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Abstract

The invention discloses a reflective all-optical fiber current sensor, which is characterized in that a sagnac interference system which consists of a polarization maintaining optical fiber coupler adopts two 1/4 wave plates and a Faraday rotator as the phase bias of light waves and adopts a single polarization maintaining optical cable as a transmission line and the reflective end surface of an optical fiber sensing ring to commonly form the reflective sensing system. An interference optical circuit further adopts a polarization multiplexer, one port thereof is welded by 90 degrees, and two polarizers are additionally added at the port of the polarization maintaining optical fiber coupler, thereby eliminating the polarization noise of a plurality of devices during the polarization transformation and the transmission. The reflective all-optical fiber current sensor with the optical circuit structure has stable light wave phase bias. Interference signals have very high signal-to-noise ratio. The circuit processed by electric signals is greatly simplified. Therefore, the phase delay generated by the circuit which is processed by the electric signals is very small. The angular difference of an actual electronic current transformer which is composed by the reflective all-optical fiber current sensor can achieve the national 0.1 level standard.

Description

technical field [0001] The invention relates to a current sensor, in particular to a reflective all-optical fiber current sensor used for measuring large current and carrying out relay protection in high-voltage lines. Background technique [0002] In order to reduce the transmission loss in long-distance power transmission, increasing the transmission voltage is an effective way. At present, current transformers composed of silicon steel sheets and enamelled copper wires are used for current measurement and relay protection in high-voltage lines. As the line voltage continues to increase, this current transformer encounters great difficulties in insulation. The quartz material used to make optical fibers is itself a good insulator. Therefore, the current transformer made of optical fiber can theoretically be used at any high voltage, and is an ideal substitute for the currently used current transformer. [0003] When the current flows in the conductor, a magnetic field w...

Claims

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Application Information

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IPC IPC(8): G01R15/24G01R19/00G02B6/26G02F1/095
Inventor 姚寿铨
Owner SHANGHAI UNIV
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