Electromagnetic current mutual inductor iron core on-line demagnetizing method

A current transformer, electromagnetic technology, applied in circuits, magnetic objects, electrical components, etc., can solve the problems of reducing measurement accuracy, affecting the working characteristics of current transformers, and high price, and achieving the effect of removing residual magnetism

Inactive Publication Date: 2006-07-05
TSINGHUA UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] The existence of residual magnetism will affect the working characteristics of the current transformer and will prevent accurate measurement
Larger residual magnetism will even affect the normal operation of the relay protection device, and even cause malfunction
[0005] In order to suppress the remanence, there is a method to use ferromagnetic materials with small coercive force, such as permalloy or amorphous materials, but the price of these materials is high, which will double the manufacturing cost of the transformer
In addition, someone proposed to open a small air gap on the iron core, but this method will increase the magnetic flux leakage and reduce the measurement accuracy, and it is not convenient to manufacture.

Method used

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  • Electromagnetic current mutual inductor iron core on-line demagnetizing method
  • Electromagnetic current mutual inductor iron core on-line demagnetizing method

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Embodiment Construction

[0012] The invention provides an online demagnetization method for an electromagnetic current transformer core. The method is to connect the demagnetization device 2 to the secondary side of the electromagnetic current transformer 1 and connect it in series with the load 3 (such as figure 1 shown). The degaussing device 2 is connected to the B terminal, A terminal and C terminal of the voltage generating circuit 5 by the cathode, anode and control pole of the power electronic switching device 4 respectively, and the current sensor 7 is connected to the signal input terminal of the voltage generating circuit 5 and then set Composed on the anode of the power electronic switching device 4. AC or DC power supply 6 is connected with voltage generation circuit 5 (such as figure 2 shown). Terminals 1 and 2 of the device are connected in series in the circuit on the secondary side of the current transformer 1, and the current sensor 7 is used to detect the working condition of the...

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Abstract

In the method, unbuilding device is connected to subsidiary side of electromagnetic type current transformer and is cascaded to load. The unbuilding device is composed of bi-directional thyristors, controlling circuits, and current transformer. Based on condition of current in circuit, or at fixed time (such as once per year), operation personnel controls the device: short circuit current passing through the unbuilding device starts it up automatically so as to remove residual magnetism on line totally.

Description

technical field [0001] The invention belongs to the technical scope of transformer manufacturing, in particular to an online demagnetization method for an electromagnetic current transformer iron core. Background technique: [0002] Electromagnetic current transformers are mainly used for energy metering and relay protection in power systems, and their accuracy is of great significance to power economy and operational reliability. Transformer manufacturers have done a lot of work to ensure their accuracy. But there is no effective method to solve the influence of remanence on the working characteristics of current transformers. Wang Xiaoqi, Guo Keqin, Yao Min, and Shi Xiao reported in the literature: "The Influence of Remanence on the Accuracy of Current Transformers. Transformers, Issue 06, 1996, 5-9", when a short-circuit fault occurs in the power system, the current transformer will Large residual magnetism is generated, and for a current transformer of class 0.2, the a...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01F13/00
Inventor 钱家骊黄瑜珑关永刚
Owner TSINGHUA UNIV
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