Simplified simulation model of continuously transposed cable for linear and nonlinear buckling analysis

Continuously transposed cable (CTC) is a multistranded conductor mainly for application in power transformers. As its structure is complicated a simplified simulation model and an easy analytic model for the buckling analysis of transformer coils are investigated in this paper. In the simplified models the transposition of the strands is neglected leading to an easy rotation symmetric cross section. These simplified models are compared to detailed models using finite element analysis (FEA) based linear and nonlinear buckling simulations. Furthermore analytical approaches are adopted from the buckling-behavior of a circular arch for the use with CTCs. All models are compared with respect to their critical buckling load for some typical winding and CTC dimensions varying between 11 to 41 strands. The maximum deviation between detailed and simplified FEA based CTC models for both linear and nonlinear buckling analysis lies below 13%. The deviations for the analytic approaches are with a maximum of 22% higher but serve to verify the trends deduced from the simulation results.