Research on radial stability of autotransformer inner winding under the short-circuit condition

The stability of the winding in the large capacity autotransformer is a complicated problem under the short circuit condition. The inner winding instability is one of the main reason for the transformer short circuit accidents, and also the weakest part of the transformer winding resisting the short-circuit impulse electric force. Therefore, the analysis of the inner winding radial stability is great significance to improve the safety operation of the transformer. In this paper, taking the 230kV autotransformer as an example, using 3D finite element method to calculate the winding internal leakage flux distribution and electric force distribution under sudden short circuit, through the short-circuit impedance calculation and measuring values compared, verifies the correctness and rationality of the model.