Analysis Of Additional Loss And Thermal Field Of Power Transformer

With the rapid development of economy in our country,the demand for more electricity grows with each passing day,at the same time,the capacity of generator unit and the scale of power grid continue to increase.Then the capacity of a single power transformer which as the main equipment power plants and substation major installation is increasing.And the result is that the transformer leakage magnetic field strength increases obviously and all additional losses arises.Therefore the local overheating problems such as the reduce of transformer's insulation performance may come up which affect the safe and stable operation and service life of transformer ultimately.So it is very important to study the transformer's loss distribution and temperature field.The basic theory of electromagnetic field and transformer leakage magnetic field are introduced in the beginning of this thesis.With a three-phase S10-120000/220 five pillar power transformer Power transformer as an example,the mathematical and physical models are established to solve the three-dimensional leakage magnetic field of transformer.And the simulation of transformer leakage magnetic field distribution are obtained by using the finite element software,on the base of the conclusion,the total value loss and the eddy current loss distribution of the winding and the metal structure are obtained by calculating the eddy current loss of each wire and metal structure of the eddy current loss.After that,through the calculation and analysis of the eddy current loss distribution of metal structure in different situations,such as installing magnetic shielding on the oil tank wall and clamp,some measures to reduce the eddy current loss of metal structure are provided.Finally,the model of solving the two-dimensional thermal and fluid field is established by the FLUENT software,and thermal and velocity field distributions of different spots in the internal of transformer are obtained.Then the distribution of temperature and flow field in the situation adding and not adding oil baffle plate is compared and analyzed,and the result showed that it has a certain positive influence to improve the flow field and temperature field distribution of the transformer by adding oil baffle plate.By the calculation and analysis on the leakage magnetic field,the eddy current loss of metal structure and the thermal field of power transformer,the thesis obtains that the eddy current loss of metal structure can be decreased by installing magnetic shielding and slotting on the tie-plate,and the temperature of transformer can be reduced effectively by raising the center height of radiator,which provides evidence and has definite instructive significance to the engineering design of power transformer.