| Improving the manufacture and design level of the generator insulation canincrease the overall manufacture and design level of large generator in China. As unitcapacity and rated voltage are rising continuously, advanced requirement is raised towinding insulation of large generator. Therefore, it is urgently a problem to be solvedhow to design a reasonable anti-corona layer structure for stator winding insulationunder26kV rated voltage.Firstly, equivalent circuit model of electric field distribution for winding insulationend of generator under different conditions are established based on circuit principle.The calculation software for electrical potential distribution on anti-corona layer isdesigned by Matlab. Furthermore, Influences of rated voltage of stator bar, resistivityand nonlinear coefficient of anti-corona material, length of anti-corona layer etc. onelectrical distribution for stator winding insulation end of generator are discussed.Then, the electric field simulation model is built according to stator bar structure,and the electric field distribution characteristic is analyzed under three dismensioncondition by COMSOL Multiphysics. Influences of lap joint structure and bar cornasize to electric distribution are discussed. The results show that：The inner corna lengthis less than outer length due to stator bend, and the potential, electric distribution andloss of inner anti-corona layer corner are higher than outer side. In particular, inner andouter side losses of wide side bar differ by twice. Extending the low resistance region soas to cover the entire corner part can eliminate adverse impact of stator bar corner, andthe interturn electric field distribution can be improved. The electric field distribution ofoverlap structure is increased, but the overlap structure has little significant impact onother parts.Finally, the combination of genetic algorithm and finite element simulationanalysis is realized by COMSOL Multiphysics secondary development module. The anti-corona structure of stator bar which rated voltage is26kV is optimized by geneticalgorithm toolbox called by Matlab. The optimization results show that: the maximumfield strength of stator bar ending is36.7percent of corona onset field strength, and themaximum loss and the potential of anti-corona are controlled in the normal range.This study is referred to26kV stator bar anti-corona layer structure design andoptimization. |
