Properties of a field-reduced twisted three-phase power cable of finite length

The object of investigation is a twisted three-phase power cable of finite length. It, contains N uniform packs built up by 3 conductors, where each of the packs carries an identical three-phase current system. With respect to the 3 arbitrary phase-currents of a pack the cable forms a closed system. The cross-sections of the 3 wires belonging to a pack are arranged along straight lines which start under corresponding angles from the center of the cable. Compared with the field of a common 3-wire cable the superposition of the N magnetic three-phase fields of the single packs leads to a reduced overall field caused by compensation effects. We express the induction of the cable analytically by the help of integrals. The numerical results are displayed as 3D-plots, induction maps and diagrams of the attenuation for cables with different pack numbers N.