Creating Bushing Core Geometries

Sammanfattning: Bushings are a necessary component of the transformers in the power grid. A bushing is used to control the electric field's strength and shape. It is also an insulator for high-voltage conductors. The bushing enables a conductor to be safely brought through a grounded barrier. In this report, several methods for creating a 2D axi-symmetrical bushing core geometry in COMSOL Multiphysics were developed. The geometry includes the conductor, hollow area inside the conductor, the RIP, the mold and aluminum foils. First, the base-geometry was constructed, which includes all geometry parts except the foils. Afterward, two different approaches were used to construct the foils. The first approach was to automatically build a requested number of foils. The second approach was to create the foils based on data from excel-sheets. The developed method should be able to create both full foils and partial foils. A total of four foil methods were developed. The first method used COMSOL's Model Builder to create a requested number of foils uniformly distributed within the base-geometry. The second method used COMSOL's Application Builder to create a requested number of foils based on mathematical expressions. The third method reads data from an excel sheet to create the foils in COMSOL. Method four is an improved version of method three that can create partial foils as well as the base-geometry. Foil methods II, III, and IV, created every foil as a separate geometrical object. As a result, an associated method that deletes the foils were also developed for each of these methods. A conclusion that the fourth method was the most realistic method of creating a bushing core could be draw due to, among other factors, it is the only method that can build partial foils.