Calculation And Analysis Of Electromagnetic Field And Losses In End Structural Components For 1000MW Hydro-generator

The hydro-generator is the key equipment of the hydropower development. For the largest unit capacity of 1000MW hydro-generator which will be made, because of the huge capacity, it is required to study well the influences of the end magnetic field for the end structural components. In this paper, according to the end structural characteristics of the 1000MW hydro-generator, the electromagnetic properties for every structural component in the end region is researched deeply from the angle of magnetic field.Firstly, the 2D finite element model of 1000MW hydro-generator is built under a pair of poles, and the field currents are calculated at no-load and rated load. On the basis of this, the values of the field current are discusses using the different size of the field windings, the different ratio of the damping winding pitch and different relative permeability in the slot wedge at different operating conditions. The effects of these factors for the field current are found by comparing with the results. Under the condition of calculating the field current accurately at rated load, the values of synchronous reactance, transient reactance and ultra-transient reactance of 1000MW hydro-generator are got.Secondly, the 3D finite element model of the 1000MW hydro-generator in the end region is given. Based on the theory of transient electromagnetic field, the distributions of the flux density in every end structural component are got at no-load and rated load. At the same time, the distributions of eddy current and the eddy current loss in the end structural components are got.Thirdly, the distributions of the circulating current and circulating current loss are obtained using full transposition, transposition with a void, inadequate transposition and elongation transposition in the stator bar. Meanwhile, the total circulating current losses of 1000MW hydro-generator are calculated with applying different transposition type.Finally, through the mixed programming about the advanced programming language Matlab and Visual Basic 6.0, the correction electromagnetic program is made. The program can provide reasonable reference for the electromagnetic design of the 1000MW hydro-generator.