Unbalanced Operations of Three-Phase Machines with Damper Circuits

A study on unbalanced short circuits of three-phase machines with additional field circuits is discussed, and a detailed solution for the case of a double-line-to-ground short circuit of a salient-pole synchrenous machine is offered. By mathematical analysis, new and complete transient solutions for short-circuit currents, torque, and open-phase voltage are derived for ready uses.