| The stator winding is usually designed as a stator bar which is made up of several strands in large AC machines.When the machine runs,the strands in a changing magnetic field produce large losses.This sends out a lot of heat.This breaks the insulation between the strands to cause a short-circuit between the strands.In this paper,taking 360 ° full transposed bar as the research object,the leakage magnetic field,strand current,circulating current losses and the influencing factors of circulating current losses are studied.According to the multi-section field-circuit coupling method,a new model of field-circuit coupling is created to calculate the strand current of the same bar in rated situation.Comparing the results of two models to verify the rationality and accuracy of the new model.Establishing the model of short-circuit fault between the strands of stator bars to solve the problem of calculating the short-circuit fault current between strands.To prove the accuracy of the model,building up the leakage magnetic field measuring platform at the end of stator bar to test the distribution of leakage magnetic field.The simulation schemes for different short-circuit fault positions and different short-circuit fault degrees between the stator bar strands are designed.The influence of the short-circuit fault position between the stator bar strands and the short-circuit fault degree between the stator bar strands on the stator bar circulating current loss is obtained to get the influence of two factors on the circulation loss.To figure out the problem of influencing factors of short-circuit fault circulating current losses between strands,designing different simulation solutions on different short-circuit fault locations and different short-circuit fault levels of strands.Exposing the law of influencing factors of short-circuit fault circulating current losses between strands by calculating the circulating current losses. |
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