Calculation Of Temperature Field And Electromagnetic Field Of Large Salient Synchronous Generator Based On Fem

In this paper, the electric and magnetic relationship and heat generating principle are researched taking the steady electromagnetic fields and temperature fields of the large salient generator as researched object. The practical operation of large salient synchronous generator is a very complex physical process. To describe this physical process exactly it is necessary to analyze from aspect of coupled fields including electromagnetic and temperature fields. Calculating the distribution of losses in stator strands based on the eddy current distribution coefficient method. It shows that results from this method and the traditional method are nearly same. So, the average method can be applied to calculate the temperature field. Because insulation layers in strands and turns are very thin, they are always be out of consideration when calculating electromagnetic fields. But the whole areas of stator strands insulation may exceed that of one piece of strand and it will have certain of effect on the calculation precision. The same effect occurs for the turn insulation.. Also the insulation layers are always ignored in the calculation and analyze of hydrogenerator. However even a thin insulation layer may have a significant temperature drop and this will have a direct effect on the machine design.According to the theory of electromagnetic fields, the large salient synchronous generator with fractional stator slot are calculated and analyzed by the Finite Element Method (FEM) in this paper. The Fourier analysis method is applied to decompose the air gap magnetic density into the basic spatial component and a series of harmonic components and wave shape eigen coefficient of air gap magnetic field are calculated. Through analyzing the air gap magnetic field, stray loss on the surface of rotor can be worked out and moreover temperature field distribution in rotor can be obtained. Longyang Gorge 320MW hydrogenerator is taken for example and the calculating results and the measured results are compared to confirm the accuracy of calculation.