Analysis of AC loss and current distribution of co-axial multi-layer cable

An analytical model to estimate the AC losses and the inter-layer current distributions of co-axial multi-layer cable conductors was developed. The inter-layer current distributions and the AC losses were numerically calculated and their dependence on the twist pitches and directions of the cables was evaluated. It was shown that when the twist pitches were longer than 200mm, the AC losses and the current distributions of the cables were not clearly dependent on the twist directions. It was also shown that the AC losses decreased and the uneven current distributions improved by decreasing the twist pitches less than 150mm.