Multi-ring all-fiber current transformer

Abstract

The invention discloses a multi-ring all-fiber current transformer comprising an acquisition unit and a plurality of sensing fiber rings. All sensing fiber rings are connected in series and the adjacent sensing fiber rings are connected by polarization-maintaining fibers; and the sensing fiber ring at the front end is connected with the acquisition unit by a polarization-maintaining fiber. The acquisition unit provides an optical signal meeting the need of the sensing fiber ring, receives an optical signal returned by each sensing fiber ring, and calculates a primary current. On the basis of the structure of the transformer, a measurement need of differential currents or combined currents of a plurality of differential-current and zero-sequence-current measurement points can be met with low costs; and the system reliability is improved.

Description

technical field [0001] The invention relates to a structure of an all-fiber current transformer configured with multiple sensing fiber rings. Background technique [0002] In the power system, the calculation of differential current is generally realized by performing differential calculation on the secondary current of two or more current transformers. For primary equipment with different voltage levels and rated currents on each side, such as the main transformer, the selected current transformers are generally of different types and have different transformation ratios, and their dynamic range and transient characteristics may be quite different. On the one hand This leads to a large differential unbalanced current. On the other hand, when an external fault occurs, it is easy to cause differential protection to malfunction. For protected primary equipment such as generators and busbars, current transformers of the same type are generally used, but due to manufacturing er...

AI Technical Summary

Problems solved by technology

Such a configuration scheme only needs one all-fiber-optic current transformer to realize the measurement of the combined current of each measuring point, which avoids the influence caused by the performance difference of each measuring point separately configured current transformer; The distance, size, and polarity of the current conductors have strict requirements. For example, some measuring points are far away, and it is unrealistic to use a fiber optic ring to measure at the same time; The imbalance of the magnetic field will greatly affect the accuracy of the measurement results of the current transformer. At the same time, the size of the sensing ring of the current transformer is very large, and the manufacturing process is difficult to guarantee; Measurement of Differential Current

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