Failure diagnostic method for dynamic stable state of power transformers

A technology for power transformers and fault diagnosis, applied in the direction of measuring electrical variables, instruments, measuring electricity, etc.

Active Publication Date: 2011-11-23
云南电力试验研究院(集团)有限公司
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Problems solved by technology

However, this method needs to be compared with the original frequency response characteristic curve to judge the deformation degree of the transformer winding. In the absence of the original frequency response characteristic curve, misjudgment or misjudgment may also occur. The impedance method is more sensitive to the deformation affecting the overall inductance. Such as radial deformation, axial twist, open circuit and short circuit between turns, etc., but not sensitive to local tension and compression between turns, overall displacement of coil, tap changer contact ablation, etc.

Method used

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Embodiment Construction

[0045] The method for diagnosing faults in dynamic and stable states of power transformers is characterized in that the fault diagnosis method adopts the combination of frequency response method and impedance method to jointly analyze the deformation of power transformer windings. Different power transformers, the same windings of different phases, the index of the correlation degree of the frequency curve in the dynamic and stable state, referred to as the correlation coefficient r, the calculation method of any correlation coefficient r relative to other phases is:

[0046] r = [∑X i Y i - m (∑X i / m)(∑Y i / m)] / SQRT{[∑X i 2 - m (∑X i / m) 2 ][∑Y i 2 - m (∑Y i / m) 2 ]}

[0047] Among them, X i , Y i Represents the difference between the corresponding values ​​of the two curves, that is, X i = X iA -X iB , Y i =Y iA -Y iB , m represents the number of sampling points of the frequency response curve, and SQRT represents the operation of finding the...

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Abstract

The invention relates to a failure diagnostic method for the dynamic stable state of power transformers. In the failure diagnostic method, the deformation condition of power transformer windings is analyzed by combining a frequency response process and an impedance process, the power transformers which have the same types and different serial numbers, the same windings with different phases and indexes of the correlation degree of frequency curves of the dynamic stable state are obtained by the frequency response process. The failure diagnostic method comprises the following steps of: analyzing the dynamic stable state of the power transformers according to related coefficients by synthesizing the advantages of the synthesize technology and the impedance process; when exceeding a permissible value, judging the related coefficients by the impedance process; and when numerical values of parameters also exceed the permissible value, determining that the failure of the dynamic stable state of the power transformers occurs.

Description

technical field [0001] The invention relates to the detection technology of a power transformer, in particular to a method for diagnosing a fault in a dynamic and stable state of a power transformer. Background technique [0002] As an important main equipment in the power system, the safe operation of the transformer will seriously affect the safe operation of the power grid. With the rapid development and construction of the power grid, more and more transformers are in operation, and many large transformer accidents are caused by the short circuit of the low voltage side of the transformer. The anti-short circuit capability of transformers has become an important index to measure transformers, and it is a necessary condition to ensure the safe operation of medium and low voltage systems in power grids. At present, the transformers operating in the Yunnan power grid have been in operation for decades. These transformers have poor short-circuit resistance and are prone to ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01R31/06
Inventor 丁心志
Owner 云南电力试验研究院(集团)有限公司
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