Transformer winding deformation refers to the irreversible change in the size or shape of the winding under the action of electrodynamic and mechanical forces. It includes changes in axial and radial dimensions, body displacement, winding twists, bulging and turn-to-turn short circuits, etc.
There are several ways to judge whether the transformer winding is deformed:
Frequency response method: By injecting the scanning signal source from one end of the winding to the ground, the frequency domain function of the characteristic parameters of the two ports of the winding is measured, and the frequency domain spectral characteristics of the port parameters are analyzed to judge the structural characteristics of the winding, so as to achieve the purpose of diagnosing the deformation of the winding.
Low Voltage Short Circuit Impedance Method: Testing is performed using a specialized Transformer Short Circuit Impedance Tester.
Comprehensive analysis method: When the winding short circuit accident occurs, in addition to measuring the deformation, some routine tests and special tests should be carried out. It is also necessary to combine the size of the short-circuit current and the length of the short-circuit time to conduct a comprehensive analysis to judge the deformation of the transformer winding.
Before the test, it is necessary to understand the on-site situation and test conditions of the tested equipment, investigate the site, consult relevant technical information, including the factory test data of the equipment, test data over the years and related procedures, etc., and master the operation and defects of the equipment. At the same time, it is also necessary to prepare test instruments and equipment.
