Capacity Optimization Of Auyotransformer Based On Magnetic Field And Temperatuer Field Analysis

With rapid development of high-speed railway in China,AT power supply has become the preferred mode for electrified railway.The Autotransformer(AT),one of the key equipment of the AT power supply system,has significant effects on the operating safety and cost of railway.However,according to statistics of railway apartment,which indicates that capacity of traction transformers was wasted generally,due to that the load characteristic of autotransformer is similar to traction transformers,this is always a problem.In order to utilize the designed capacity of transformer effectively and cut the operation costs,it is necessary to optimize the capacity of transformer in the context of safety and dependability of traction power supply.First this article established the OD-25000/55 autotransformer three-dimensional model by using Ansoft Maxwell electromagnetic simulation software,then did research systematically by using electromagnetic field theory and finite element method.Through the ampere-turns balance principle to prove the validity of this model,simulated the core loss distribution of autotransformer during no-load period,and then block division of transformer core on the basis of this.Calculated and analyzed the distribution of the transformer winding leakage magnetic field,extracted horizontal and vertical magnetic flux leakage vortex of each winding and its corresponding eddy current loss value.Then OD-25000/55 type numerical calculation model of autotransformer was built with the finite element software Ansys Fluent,and simulated and analyzed the internal temperature field distribution of the steady state under rated condition.Then explored the relationship between the train and the winding current,the influence between train running state influence on winding current,the influence of the power supply distance and the speed of the train on autotransformer load time,and studied the autotransformer temperature characteristics under different load curve.Finally calculated the structure of the autotransformer with three different capacity,analyzed the influence of the external environment on life lost,analyzed the corresponding life loss based on the temperature characteristic of autotransformer with different capacity under computational load curve,according to the load curve to choose the appropriate capacity of autotransformer,analyzed the economy of autotransformer with different capacity under the same load.On the premise of meeting the requirements of temperature rise limit and the loss of insulation life to reduce transformer capacity and electricity expenses as far as possible,then improve the economic benefits of railway.