Method for estimating remanence of power transformer based on winding deformation measurement

Abstract

The present invention provides a method for estimating remanence of a power transformer based on winding deformation measurement. The method utilizes a continuously adjustable low-frequency sine wavepower source of a voltage and a frequency to excite the power transformer to preset different sizes of remanence Br in the transformer core, measures a winding frequency response curve of the transformer under different remanence sizes, read a resonance point frequency f0 of the winding frequency response curve at low frequency band, and obtain a series of discrete (Br, f0) values to establish a relationship curve model between Br and f0. After the model is established, the resonance point frequency of the winding frequency response curve at the low frequency band can be read, therefore, the remanence of the transformer core can be estimated through measuring the winding frequency response curve of the transformer. The method only needs to measure the winding frequency response curve of the transformer one time, can effectively and quickly estimate the sizes of the remanence of the core of the power transformer, has simple operation, and high efficiency, and is of great significance for analyzing the remanence state of the core of the power transformer.

Description

technical field [0001] The invention relates to the field of remanence estimation of power transformers, in particular to a method for estimating the magnitude of remanence of power transformers based on winding deformation measurement. Background technique [0002] For a transformer with a closed ferromagnetic material core structure, after the DC resistance test and other test items and during the cut-off operation, due to the closed core structure and the hysteresis characteristics of the ferromagnetic material, there will be residual in the core. Magnetism, for large power transformers with more winding turns, the more residual magnetism will be generated under the action of DC magnetization. If there is residual magnetism in the transformer, there will be a large excitation inrush current in the air-closing transformer, which will have an important impact on the AC and DC power grid. Therefore, it is of great significance to accurately judge the residual magnetism of t...

AI Technical Summary

Problems solved by technology

[0003] However, at present, the residual magnetism cannot be directly measured, and there is a lack of accurate technology for transformer residual magnetism measurement. As a result, it is impossible to know the residual magnetism under various conditions such as after the on-site direct resistance test and after the circuit breaker is opened.

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