The Research And Optimization Of Metal Defect Partial Discharge In 110kV Basin-type Insulator

The 110 kV basin-type insulator was studied in this paper with specific characteristics of total box of three-phases,existing metal flange and the basin-type insulator without using full shielding inner rings.The combination of finite element calculation and experiment methods was being used.The surface electric field of basin-type insulator with metal particles along the surface was calculated and the partial discharge of 110 kV basin-type insulator with flange metal defects exist was studied.The 3D structure model of 110 kV basin-type insulator was established by using the actual production drawings.The finite element method was used to calculate and analysis the surface electric fields of different locations on the basin-type insulator and different sizes of metal particles.The calculation was shown that the amount of distortion of local electric field caused by metal particles would increase along with the growth of the surface field strength of metal particles located in different position under the effect of power frequency voltage.The amount of distortion of local electric field caused by metal particles would increase along with the growth of diameter of metal particles.The calculation results was shown that the surface electric field of basin-type insulator was concentrated because the presence of metal particles,especially the normal component of surface electric field was magnified.Therefore the hidden danger of surface flashover existed.The tests of manually setting metal particles defect was shown that basin-type insulator metal particles was caused by the hidden danger of surface flashover.The experiment was verified the effectiveness of the theory and the reference of basin-type insulator structure design and the electric field simulation was provided.Secondly,the main reason of partial discharge caused by flange metal defects based on the actual production tracking was summarized combining the theoretical analyses and experiment verifications.In view of the problems found,three electric field optimizations including adjusting the width of the gap,adopting full-shielding inner rings and adopting the ground conductor sealing rings instead of traditional sealrings were proposed in this paper;the theoretical analysis and experimental verification demonstrated the effectiveness of three kinds of optimization scheme.At last,on the basis of structure characteristics and design elements of shielding inner rings,the structure of shielding inner rings was optimized with the Genetic Algorithm.In order to reduce the maximum electric field of basin-type insulator terminal gap and the field of junction of shielding inner rings and basin-type insulator,the optimized objective function and corresponding optimization mathematical model was established.The optimization calculation was shown the sensitivity of design variables to objective functions,the analysis results of responding surface and three groups of optimal solution.The key selection factors for the solution reduced the production costs.One of the set of optimal solutions was chosen for the final structure parameters.The maximum electric field of junction of shielding inner rings and basin-type insulator was reduced by 9%,the maximum electric field of basin-type insulator terminal gap was reduced by 21%,the goal of optimization was achieved and the design efficiency was improved.