Analysis of Armature Current and Magnetic Force at Rotor Dampers in Superconducting Generator on Sudden 3-Phase Short-Circuit.

Abstract

The important design factor of superconducting generator is the estimation of the electromagnetic forces at the rotor dampers on sudden three-phase short-circuit. In this paper, the armature current and electromagnetic forces on sudden three-phase short-circuit are directly simulated by two-dimensional transient analysis, considering the following complex terms.(1) Induced current by the speed electromotive force caused by the rotor rotation. (2) The connection of three-phase windings. (3) The resistance and reactance at the armature coil-end.The speed electromotive force is considered by using the combination method, which is FEM combined with BEM at the air gap. The connection of the armature winding and the effect of the armature coil-end are considered by using the analysis combined with the external circuit equations. Moreover, the effect of the Roebel-transposition of the armature winding is approximately considered.By the authors, analysis, the electromagnetic forces at the rotor dampers can be calculated with a high accuracy.