Evaluation of HVDC cable impedance and admittance matrices by finite element method
Résumé
In this work, a 2D Finite Element Method (FEM) is used to calculate the frequency dependent impedance and admittance matrices of underground and submarine cables. A harmonic magnetodynamic formulation is used to calculate the series impedances, and for the calculation of the parallel admittance an electrodynamic formulation is applied. The frequency response of the cable was obtained by coupling the FEM method with an external electric circuits. This technique allows the physical representation of the nonlinear behavior of the frequency dependence of the cable parameters. The numerical results are compared with those obtained from commonly used analytical formulations and other methods available in the literature. Different surrounding environment cases are treated, and their effect is shown in frequency. Time domain simulations under fault circumstances point out the necessity of an accurate cable model. Current and voltage measurements are the input of protection algorithm and breaking decision depends on these values. Therefore, the use of a precise method is mandatory.