Parametric Modeling Of Large Generator Stator Bar And Development Of Numerical Simulation System

With the gradual acceleration of the modernization,the demand of China for electricity is increasing,which puts forward higher requirements on the capacity and rated voltage of the generator.The rated voltage increase of the generator is often enslaved by the main insulation.Therefore,the study of insulation materials and insulation structure is very important for the development of large generators.The end model and internal shielding model are built through the method of parametric modeling based on the finite element method.Taken a hydroelectric generator with a rated capacity of 120 MW and a rated voltage of 15.75 k V as an example,the electric field distribution of unshielded model and four kinds of internal shielding model is analysised by using the finite element method.The electric field distributions of various models is discussed in different fillet radii,different shield thicknesses and different distances between shield layers and strands.Taken semiconductor laminate structure as an example,the influence of the distance between exposed copper points on the electric field distribution on the semiconductor is discussed.And the distribution of the electric in the field of insulation at different transposed angles of the unshielded structure is discussed.At last constructed the App of end model and transposition model which are used to calculate the electric field.The electric field of the unshielded structure is mainly concentrated on the outer corner of the strand and the position of transposition,which fluctuates periodically along the length of the bar;The electric fields of the four shielding structures are mainly concentrated on the four outer corners of the shielding layer and the electric field distribution along the length of the wire bar is uniform.The maximum electric field and average electric field of the four kinds of internal shielding structures decreased with the increase of the fillet radius of the semiconductor,and increased with the thickness of the inner shield and the shield distance from the strand increases.All of these structures apart from semiconductor laminate structure have reduced the maximum electric field by about 40%;Taking the semiconductor laminate as an example to explore the effect of the distance between the exposed copper points on the electric field distribution,with the gradual increase of the separation distance,the electric field intensity on the shielding layer is increased too.So it is recommended that the distance should not exceed the distance of 6 pitch;Taking the unshielded structure as an example,the electric field distribution in the insulation at different transposed angles is discussed,the maximum electric field and the average electric field increases with the increase of the transpose angle;The electric field calculation App of the end and the groove has realized the automatic operation of modeling and electric field calculation.