U-shaped current transformer with on-line insulation-monitoring function

Abstract

The invention relates to the field of power current transformers, and discloses a U-shaped current transformer with on-line insulation-monitoring function. The current transformer comprises a primary conductor having a U-shaped structure, a zero screen, a middle screen, an end screen, insulating layers and a secondary winding, wherein the zero screen, a middle screen, a end screen are lapped and wound on the primary conductor in turn; the insulating layers are arranged between the primary conductor, the zero screen, the middle screen and the end screen in turn; and the secondary winding is sleeved on the end screen. The current transformer is characterized in that the current transformer also comprises a differential current transformer; the end screen at the bottom of the U-shaped structure is divided into a left half end screen and a right half end screen which are mutually insulated and lead out a left lead wire and a right lead wire respectively; the left lead wire and the right lead are electrically connected with the differential current input end of the differential current transformer; and the differential current output end of the differential current transformer outputs current signals representing the insulating state of the U-shaped current transformer.

Description

technical field [0001] The invention relates to the field of power current transformers, in particular to a U-shaped current transformer with an online insulation monitoring function. Background technique [0002] At present, power current transformers are mainly oil-immersed upright, and its primary conductor is a traditional U-shaped structure, and its main insulation is transformer oil and cable paper insulation structure, which is mainly wrapped by cable paper tape. In order to make the internal electric field relatively uniform, a group of main screens are arranged inside the insulating layer and end screens are provided at the ends of the main screens. Another new type of insulation structure of oil-immersed vertical current transformers has been more and more widely used, that is, only the outermost and innermost two main screens (last screen and zero screen) in the insulation layer are reserved, and the above two The main screens (intermediate screens) between the m...

AI Technical Summary

Problems solved by technology

[0003] The existing method of on-line monitoring current transformer insulation is by monitoring the dielectric loss tanδ of its insulation. To achieve this goal, it is necessary to accurately collect and calculate the phase difference between the current signal and the fundamental wave of the voltage signal; the above-mentioned monitoring method requires many detection equipments, High precision, large investment, rarely used at present

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