Harmonic behaviour of HVDC cables

The paper deals with harmonic analysis of HVDC submarine cables. The longitudinal series impedance matrix is computed with reference to armoured cables. The results are also compared with Finite Element models showing a very good agreement. This investigation can be considered the first step of more detailed further analysis about the propagation of harmonics on the d.c. and a.c. sides. Some novel matrix procedures are presented in order to pass from the loop impedance to the longitudinal series impedance matrix and to eliminate the grounded conductors. Comparisons with ATP-EMTP are not possible for a four metallic layered (core, screen, reinforcement and armour) HVDC cable since ATP-EMTP only takes three metallic layered cables into account.

► The longitudinal series impedance matrix is computed with reference to armoured HVDC cables.
► Harmonic behaviour of HVDC cables is deeply investigated by means of both self-made series impedance matrix method (SIMM) and FE models.
► Good agreement between SIMM and FEM.
► Elimination of grounded conductors and passage from loop impedance to longitudinal series impedance matrix by some novel techniques.
► The paper has demonstrated that HVDC cables, at harmonic frequencies, behave as a coaxial cable (so giving, in fact, no electromagnetic interferences).