Simulating calculation method of influence of accumulative effect on short-circuit withstanding capacity of transformer

Abstract

The invention discloses a simulating calculation method of the influence of an accumulative effect on the short-circuit withstanding capacity of a transformer. The method includes the steps that according to an actual structure of the transformer, a three-dimensional finite-element electromagnetic field simulation model is established; before the accumulative effect is calculated, when a three-phase symmetric short-circuit Imax is introduced into the three-dimensional finite-element electromagnetic field simulation model, a magnetic leakage field of the transformer is calculated, and according to the magnetic leakage field, the maximal short circuit current I1 of the transformer is calculated; preset deformation defects are added into the three-dimensional finite-element electromagnetic field simulation model, and a three-dimensional simulation defect model of the transformer after the accumulative effect is obtained; after the accumulative effect is calculated, when the three-phase symmetric short-circuit Imax is introduced into the three-dimensional simulation defect model, the magnetic leakage field of the transformer is calculated, and according to the magnetic leakage field, the maximal short circuit I2 of the transformer after the accumulative effect is calculated; the I1 and the I2 are compared, and the influence of the accumulative effect on the short-circuit withstanding capacity of the transformer is obtained. According to the simulating calculation method of the influence of the accumulative effect on the short-circuit withstanding capacity of the transformer, the purpose of simulation experiments is achieved through a simulation method, and the simulating calculation method is easy to implement and low in cost.

Description

Technical field [0001] The invention relates to the field of transformer simulation calculation, in particular to a simulation calculation method for the influence of cumulative effects on the transformer's short-circuit resistance capability. Background technique [0002] Transformer is one of the most important equipment in the power system. Its operating conditions not only affect its own safety, but also affect the stability and reliability of the entire power system. With the rapid development of the National Grid, the short-circuit capacity of transformers continues to increase, which brings greater risks to the safe operation of transformers. The short-circuit current experienced by the transformer increases, and the short-circuit dynamic force experienced by the winding also increases. After the transformer has experienced multiple short-circuit impacts, the winding will deform after the short-circuit dynamic force accumulates. In severe cases, the internal insulation of ...

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Problems solved by technology

[0004] However, at present, there are few analyzes on how the short-circuit resistance capacity of the transformer, that is, the maximum short-circuit current, will change after the winding of the transformer is deformed due to the cumulative effect.

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