Magneto-optical balance type optical fiber current transformator

Abstract

The invention discloses a magneto-optical balance type optical fiber current transformator which can inhibit a birefrigent effect caused by a plurality of factors during optical fiber measurement on the basis of inheriting obvious characteristics of the conventional optical fiber current transformator. The magneto-optical balance type optical fiber current transformator can improve the accuracy of measuring optical fiber detection current and realize engineering application of the optical fiber current transformator.

Description

technical field [0001] The invention relates to a current transformer for measuring and detecting a large current, in particular to an optical fiber current transformer for measuring and detecting a large current in an ultra-high voltage occasion. Background technique [0002] With the continuous increase of the transmission capacity of the power system and the increase of the grid voltage, the electromagnetic current transformer (Current Transformer, CT), which is widely used above 110kV, has exposed many shortcomings: prone to explosion; magnetic saturation phenomenon; bulky; Susceptible to interference from the surrounding electromagnetic environment. Compared with the traditional electromagnetic current transformer, the optical current transformer (OCT) does not have the above disadvantages, and even has higher accuracy, which has received extensive and in-depth attention. [0003] Optical current transformer OCT, according to whether the working unit in the high-voltag...

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Problems solved by technology

[0002] With the continuous increase of the transmission capacity of the power system and the increase of the grid voltage, the electromagnetic current transformer (Current Transformer, CT), which is widely used above 110kV, has exposed many shortcomings: prone to explosion; magnetic saturation phenomenon; bulky; Susceptible to interference from the surrounding electromagnetic environment

[0006]The disadvantage of this scheme is that when the measured current i1 is large, the Faraday deflection angle Δθ1Increase, the condition of Δθ1≈sin(Δθ1) will not be satisfied, the output light intensity of analyzer A and the measured current i1 leads to a decrease in the accuracy of the detection results; in addition, the linear birefringence effect of the optical fiber will cause the circularly polarized light that should be output to become elliptically polarized light, further aggravating the relationship between the light intensity and the measured current. non-linear relationship

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