The outlet mode of the existing injection-based stator ground protection for large generators under the condition of high transition resistance ground fault is to send a signal

which fails to promptly clear the fault

allowing the fault arc energy to accumulate continuously. In severe cases

the stator core and winding insulation can be burned out as a result. Considering that the grounding transition resistance cannot truthfully reflect the fault arc energy

this paper utilizes the fault arc power to represent the severity of the fault and proposes a real-time calculation method for fault arc power. Based on the existing protection methods

an inverse-time stator ground protection for large generators is constructed by utilizing fault arc power. To limit fault arc damage to a “slight” level

the protection action delay under high transition resistance ground fault conditions is determined

thereby maximizing the safety of generator equipment. It has been demonstrated through simulation and dynamic model experiment results that the proposed method is insensitive to the ground fault location or the transition resistance. A calculation error within 1% is achieved

which is sufficient to meet the requirements of practical engineering applications.