Method for determining existence of residual magnetism in transformer iron core

Abstract

The invention provides a method for determining existence of residual magnetism in a transformer iron core. The method comprises the following steps: S1, carrying out full demagnetizing on a transformer iron core, measuring a winding deformation curve of the transformer after demagnetization, and using the curve as a filing curve; S2, comparing the measured winding deformation curve of the transformer with the filing curve to determine whether the transformer iron core has residual magnetism; indicating no residual magnetism existence of the transformer under the condition of complete overlapping of the two curves at a low frequency band; and otherwise, indicating the residual magnetism of the transformer iron core. According to the method, the operation becomes simple; the criteria are simple and clear; the efficiency is high; and whether the transformer iron core has the residual magnetism can be determined effectively and rapidly.

Description

technical field [0001] The invention relates to the technical field of transformers, in particular to a method for judging whether there is residual magnetism in an iron core of a power transformer. Background technique [0002] my country has a vast territory, and the reverse distribution of energy resources and energy demand objectively determines that my country needs long-distance and large-capacity power transmission technology. Due to its unique advantages, high-voltage direct current transmission plays an important role in long-distance power transmission. Since Gezhouba-Nanqiao my country's first cross-region, cross-system, ultra-high voltage, large-capacity, and long-distance DC transmission project in 1989, DC transmission technology has been continuously developed in my country. Up to now, the cross-regional DC transmission capacity has exceeded 50GVA, the pattern of my country's AC-DC interconnected large power grid has basically taken shape. [0003] With the ra...

AI Technical Summary

Problems solved by technology

At present, commonly used transformer residual magnetization elimination methods include AC demagnetization method and DC demagnetization method. These two methods have achieved good results in practical applications, but there is no standardized demagnetization standard, and it is impossible to evaluate the demagnetization effect. It can be judged by experience that there may still be a large residual magnetism in the transformer core after demagnetization

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