Optimization Design Of Structure For Foil-Winding Transformer

Foil-winding transformer which the thesis researches is a relatively new dry-type transformer compared with conventional transformer. It’s LV winding is not wound with flat type copper wire but foil that width is close to height of yokes. There are many merits in foil-winding transformer such as lighter weight, less ingredient, stronger Anti-short circuit ability, high efficiency of production etc. But because of exist of leakage magnetic field, there is a problem of crowded flow effect in LV foil-winding that current distributes very nonuniformly, which leads to local overheating and less working life of transformer.On the base of rational simplifying to SCB9-2500/10foil-winding transformer, we build dimensional finite element model to it. Besides, according to steady state short circuit, we set up the field-circuit coupling model with constructing the external circuit. Then A.C.loss, distribution of leakage magnetic field and current in foil windings are calculated in MagNet, we analyze the problem what results in the crowded flow effect and then obtain the proposal that resolves the problem of local overheating——improving transformer model’s structure. At last we inspect and verify validity of this proposal to the crowded flow effect and summarize the other problem else the improvement brings about.At last, the thesis analyzes the problems from thermology and sets up thcrmodynamic parameters for foil-winding transformer’s simplified model. By taking advantage of magnetic-thermo coupling mode, we calculate and obtain the distribution of temperature in transformer in case of steady state short circuit in ThermNet and watch the appearance of the crowded flow effect in the LV windings more intuitively. By comparing with different models’temperature field, we further inspect and verify feasibility of the proposal to the crowded flow effect.