Structural Optimization In Anti-corona Coating Of Generator Coil Insulation System And Experimental Research

Because of the electric field concentrating, there will be corona even dischargehappened probably on the notch of generator end-winding. The happening of coronawill reduce the longevity of motor coil and lead to the occurrence of serious incidents. Italso limits the enhancement of generator power capacity. As the development of electricpower system and the increasing demand for higher power generator capacity, thedesign of anti-corona coating structure and materials for generator end-winding statorcoil become the most effective method to solve the problem of corona happened ongenerator end-winding, enhance the generator capacity and decrease the generator’ssize.The method which disperse the SiC particle and dissolve the epoxy lacquerseparately is used to mix the nonlinear anti-corona paint for generator with600meshSiC and1200mesh SiC, and make the high-voltage electrical conductivity test to them.Then discuss the influence of different SiC particle size and different SiC content on theresistivity and nonlinear coefficient of nonlinear anti-corona paint. Mix the SiCnonlinear anti-corona paint by OMMT/epoxy composite with OMMT content for2wt%~6wt%and make a comparison for electric properties to the SiC nonlinearanti-corona paint with pure epoxy. Then get the conclusion that the addition of OMMTin OMMT/epoxy composite can improve the nonlinear coefficient of corona paintwithout changing the resistivity ρS.Do the finite-element simulation calculation on the3D model of two sectionnonlinear anti-corona structure for generator end winding stator coil by the software ofmulti-physics coupling simulation, COMSOL Multiphysics, to obtain its maximumelectric field, maximum surface loss density and the relative voltage of the end of high resistance anti-corona coating to the coil. Then transfer the process of finite-elementsimulation calculation of generator end winding anti-corona structure to M-file script bythe secondary development function of COMSOL Script file. Rewrite the program ofthe script file to function file under the MATLAB interface and make the optimizingcalculation to function file by the variable range with the result of testing to materialsand GA toolbox of MATLAB. After that, get the optimal solution of the structuralgeometry parameters and materials properties parameters of generator end windinganti-corona structure.Overlay the anti-corona paint which matched the materials properties of theoptimal solution on the surface of aluminum rod according to optimized structuraldimensions and make the high-voltage test to verify the simulation optimization resultof nonlinear anti-corona structure meet the demand of corona condition and surface lossdensity.