Skin effect in large bi-media power conductors.

摘要

This dissertation work presents the development of a novel closed-form mathematical solution for calculating AC resistance in conductors of two different media using current density. Current density is non-uniform under AC current, and is directly responsible for the increase in AC over DC resistance of a conductor. Therefore, a solution is presented using the current density distribution under AC operation. This solution is then expanded to a conductor using two different media. Results using the obtained closed-form solution are validated against the solution using multiphysics finite element analysis (FEA). These theoretical results are then confirmed with laboratory measurements. Optimized bi-media conductor designs are determined by solving the AC current density equations and selecting the appropriate media proportion to minimize conductor AC resistance. These optimized designs are evaluated against all types of existing large segmented copper power conductors of equal AC resistance and shown to reduce cost and weight. Additionally, an extensive analysis is presented such that cost ratios of the two media can be used to determine cost effectiveness. Finally, given the complexity of the analytical solution, simplified calculation methods are proposed that demonstrate the practicality of their implementation.