Double-framework common-winding current transformer structure and design method thereof

Abstract

The invention discloses a double-framework common-winding current transformer structure and a design method thereof, the current transformer structure comprises an ultracrystalline iron core and a silicon steel sheet iron core, the ultracrystalline iron core is a closed iron core, and the silicon steel sheet iron core is provided with an air gap. In the structural design of the current transformer, when the exciting current and the iron core error are solved, two conditions of opening and closing an iron core and an air gap iron core are solved respectively. The current transformer adopts a double-iron-core framework design, the iron core which is mainly used for protection is provided with an air gap, so that adverse effects caused by protection can be effectively avoided, a measurement function can be realized in case of low current, and when a power system has a fault and has relatively high current, the closed iron core for measurement is saturated, and the current flows through the air gap iron core, so that the measurement is realized. Because the magnetic resistance of the air gap iron core is far greater than the magnetic resistance of the closed iron core, a saturation phenomenon does not exist under a large current condition, so that large current monitoring can be realized to achieve a protection effect.

Description

technical field [0001] The invention belongs to the technical field of current transformers, and in particular relates to a structure and a design method of a double-skeleton common-winding current transformer. Background technique [0002] Current transformers are important equipment for power measurement, fault diagnosis and power system condition monitoring, and are widely used in substations and power plants. The iron core structure of traditional current transformers generally adopts a closed-loop design. This design makes the iron core only have a very small magnetic impedance. When a large current component occurs on the primary side, the iron core is easily saturated. For example, the saturation of the iron core will cause the measurement error of the current transformer; for the protection current transformer, the saturation of the iron core will make the current transformer lose its protection margin, which will cause the current transformer to fail to monitor when...

AI Technical Summary

Problems solved by technology

[0003] In recent decades, intelligence and miniaturization have gradually become the new characteristics of the development of power system automation technology. Traditional current sensors are often installed separately and independently according to their functions. Two windings and two coils are used to realize the functions. Due to the disadvantages of high cost, large volume, poor transient characteristics, and small dynamic range, traditional independent sensors have been difficult to meet the needs of further development of power systems

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