In engineering applications，traditional injecting source-based stator ground fault protection that relays on injection and measurement at the secondary side of a grounding transformer is largely influenced by the parameters of the grounding transformer.Large measurement errors could be caused by inaccurate compensation or circuit parameter changes，and may lead to relay mal-operations or tripping failures.The scheme of traditional injecting source-based stator ground fault protection is introduced，and the influence of grounding transformer parameters is analyzed.An improved protection scheme that do not need impedance compensation on basis of traditional protection scheme is proposed as well.Test results from dynamic simulation verify that the improved scheme satisfies the demands of stator ground fault protection，avoids measurement errors caused by inaccurate compensation and circuit parameters change，and also increases the reliability.