  This paper analyzes different ways to simulate electromagnetically three-core
armored cables in 3D by means of the finite element method. Full periodic
models, as lengthy as 36 m, are developed to evaluate the accuracy when
simulating only a small portion of the cable, as commonly employed in the
literature. The adequate length and boundary conditions for having the same
accuracy of full periodic models are also studied. To this aim, five medium
voltage and high voltage armored cables are analyzed, obtaining the minimum
length of the cable that may be simulated for having accurate results in
shorter time and with less computational burden. This also results in the
proposal of a new method comprising the advantages of short geometries and the
applicability of periodic boundary conditions. Its accuracy is compared with
experimental measurements and the IEC standard for 145 kV and 245 kV cables.
The results show a very good agreement between simulations and measurements
(errors below 4 %), obtaining a reduction in the computation time of about 90
%. This new method brings a more effective tool for saving time and
computational resources in cable design and the development of new analytical
expressions for improving the IEC standard.
