Numerical treatment of floating conductors based on the traditional finite element formulation

Abstract

A method to model a conductor with undefined potential (commonly known as floating conductor), is sometimes required in the electric field analysis. This paper presentsand compares the main methods to deal with such issue, based on the traditional finite element formulation. The purpose is to guide the reader in the selection of a method under the following criteria: Accuracy, implementation and simplicity. The accuracy of each method was evaluated against the analytic solution of the capacitance matrix for a system of parallel cylindrical conductors. Based on the results of the simulations, the characteristics of the methods and this paper’s criteria, a qualification of each method performance is done. Additionally, particular cases in which a specific method could be the most suitable option to deal with floating conductors, are analyzed. In general, the Virtual Permittivity method exhibits the best performance. However, it is shown that the method’s accuracy is influenced by the rounding errors. This paper proposes an additional consideration on the method formulation in order to verify the accuracy of the results.