Stress Analysis Of Transformer Winding Deformation

Power transformer is one of the most expensive and important device in the power system, their operational status not only affect their own safety, but also affect the stability and reliability of the entire power system.With the rapid development of economy and the increase of network capacity, the consequences by the failure of power transformer will be more severe. Therefore, improving the reliability of power transformer operation and maintenance standards is very important to the safe operation of the entire power grid.In this paper, we take an actual transformer as an example and have studied the leakage field, the short circuit power, the strength of the winding and the cumulative effect of short-circuit. A few aehievements have been obtained.The transient electromagnetic field and the short-circuit electromagnetic force are calculated based on ANSYS, and the law of their distribution is gived.We get the maximum stress value of winding wire, and determine the structural stability under short-circuit conditions by comparing this value and the design value of resistance. The cumulative effect of transformer windings under multiple short-circuit is carefully studied by changing the windings geometry, and concluded that the stress of inner winding will sudden increases with the increase of deformation. We studied the reactance value trends by changing the size of windings, then get the law between reactance and the windings deformation.The stress analysis of transformer winding and the cumulative effect of short-circuit proposed in this paper has contribution to the maintenance and prediction for transformer short-circuit failure.