A FEM approach to calculate the impedances of shielded multiconductor cables

A procedure based on the finite element method (FEM) is proposed for the calculation of the p.u.l impedance matrix of a shielded multiconductor cable. The procedure consists in the numerical solution of the time-harmonic eddy current equation by applying impedance network boundary conditions (INBCs) on the surfaces of the shield and impedance boundary conditions (IBCs) on the surfaces of the inner wire conductors. This approach permits to avoid the FEM fine discretization of the conductive regions at high frequency and it is suitable to analyze complex cable configurations. The proposed method is presented and compared with other traditional analytical and numerical techniques to solve this kind of problem. Simple numerical examples are finally given.