FEM simulation of dynamic response of flexible busbar systems under alternating short-circuit currents

This paper investigates dynamic responses of flexible busbar systems under balanced three-phase alternating short-circuit (SC) currents using finite element method (FEM) simulations. In current industry design standards and practices, a simplified static approach is usually adopted to estimate the SC effects, which is valid only for regular structures and often leads to overly conservative results due to the fact that the configurations of the busbar system are usually over-simplified. A flexible busbar system is geometrically similar to a suspension bridge, which involves geometry-nonlinear behavior of flexible busbars (sometimes called cables or conductors), making analytical solutions of such problems complicated. Five different simulation scenarios are included in order to investigate effects of number of subconductors per phase, dropper and insulator, spacer, and pinch. The pinch effect is modeled via setting up contact pairs. It is found that the short circuit has a dominant effect on twin-subconductor systems, but not on single-subconductor systems. The inclusion of droppers, insulators, and spacers for twin-subconductor systems is found to decrease the structural responses in general. The phenomenon of pinch is clearly captured. It is found that the structural response is more conservative if the system does not include the consideration of pinch. The approach adopted in this study can be extended to analysis of similar structures, such as transmission lines under SC, as well as for busbar systems with irregular supporting structures.