To improve the low-voltage-ride-through capability of doubly fed induction generators, electromagnetic characteristics of a DFIG under short-circuit faults at grid are studied. Based on the simplifications of the grid, stator flux dynamics are respectively studied both at appearance and clearance of a three-phase short-circuit fault, utilizing circuit switching rule as well as KVL and KCL principles. Simulations on DFIG’s stator fluxes and rotor currents are done under faults of different types and at different locations of the grid. It’s revealed that stator flux of DFIG will abruptly change to its steady-state value at fault clearance with low resistance-reactance ratio of transmission lines, arousing no transient DC flux components in stator. Therefore no transient inrush currents will be induced in rotor at fault clearance. Studies and simulations verify that the electromagnetic characteristics of DFIG at fault clearance are different from those at fault appearance.