Method for transformer excitation surge current latching

A technology of exciting inrush current and transformers, applied in electrical components, emergency protection circuit devices, etc., can solve the problems of failure to be quickly removed, long blocking time, etc., to improve the protection action speed, realize the effect of low threshold and reliable blocking protection

Inactive Publication Date: 2011-04-27
XUJI GRP +1
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Problems solved by technology

[0004] The purpose of the present invention is to provide a method for blocking inrush current of transformers, so as to solve the problem that the existing identification blocking method has long blocking time and the fault cannot be removed quickly

Method used

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  • Method for transformer excitation surge current latching
  • Method for transformer excitation surge current latching
  • Method for transformer excitation surge current latching

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Embodiment Construction

[0031] Combine below Figure 1 to Figure 6 , the principles and working steps of the present invention are described and demonstrated in detail.

[0032] One, such as figure 1 Shown is the logical block diagram of the implementation scheme of the present invention for the blocking method of transformer excitation inrush current, by figure 1 It can be seen that the implementation process is as follows:

[0033] ①. Measure the second harmonic content and the third harmonic content in the three-phase differential current, and calculate the effective value of the second harmonic component in the three-phase differential current, which is equal to the second harmonic component in the differential current of each phase The difference between the harmonic content and 0.5 times the third harmonic content, as shown in formula (1);

[0034]

[0035] (1)

[0036]

[0037] in, , , Respectively, the second harmonic content of A, B, and C phases;

[00...

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Abstract

The invention relates to a method for transformer excitation surge current latching. Compared with the conventional latching method, the second harmonic single-phase latching principle is adopted, the method solves the problem that the latching time is too long when the regional external fault of an air-drop fault transformer is converted into a regional internal fault of heterogeneous phase in the conventional latching scheme and the problem that the fault cannot be quickly cut off, the speed of protection action is greatly improved, and safe operation of the transformer is ensured; meanwhile, under the condition that the protection is in normal surge current, latching protection can be reliably performed, and error operation of current differential protection is prevented; and the implementation of the method does not raise higher requirement for the conventional protective platform, the implementation threshold is low, and the method is convenient for popularization and use.

Description

technical field [0001] The invention relates to a differential protection method for a power system transformer, in particular to a method for blocking excitation inrush current of a transformer. Background technique [0002] The transformer is an essential and important equipment in the power system. In order to prevent serious damage to the transformer when an internal fault occurs, usually a large-capacity transformer must be equipped with a current differential protection as the main protection; the basic principle of the current differential protection is Kirkho husband's law. When the transformer performs no-load closing and external fault recovery, it is usually accompanied by the generation of excitation inrush current, which may easily cause the malfunction of current differential protection. In order to avoid this situation, the current differential protection of the transformer must set the blocking criterion of the inrush current. The characteristics of the exc...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02H7/045
Inventor 张振华张红跃宋宏涛柳明赵艳茹徐玉洁胡晓静
Owner XUJI GRP
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