In the production of dry-type transformer, its internal structure is more complex, no matter which part of the fault will affect the stability of dry-type transformer operation, we need to do a good job of monitoring each component. Among them, the winding deformation of dry-type transformer is one of the important reasons for the damage accident of dry-type transformer, so what method do we have to judge whether the winding of dry-type transformer is deformed?
There are three ways to judge whether the winding of dry-type transformer is deformed or not.
1) In order to correctly judge the deformation of dry-type transformer, the original data of winding deformation is measured when the dry-type transformer is delivered and installed, leaving "fingerprint" for later comparison. The test items should be complete as far as possible, including short circuit impedance value, special instrument and frequency response method.
2) After winding short-circuit accident, in addition to measuring deformation, some routine tests and special tests should be carried out, and combined with short-circuit current and short-circuit time, comprehensive analysis should be carried out to judge the winding deformation of dry-type transformer.
3) When the frequency response method is used to judge the deformation of dry-type transformer, in addition to whether the frequency response characteristics of the three-phase windings are consistent, but also according to the correlation coefficient r value between the three-phase waveforms drawn. If R value is greater than 1.0, it means that the deformation is not obvious. If R value is less than 1.0, attention should be paid to it.
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