Generator protection methods and systems self-tuning to a plurality of characteristics of a machine

A method for detecting stator ground faults in a generator is described. The method includes receiving a neutral voltage signal from a neutral point of a stator, receiving a plurality of terminal voltage and current signals from the stator, deriving a magnitude of a harmonic component from the neutral voltage signal, deriving a total complex power from the terminal voltage and current signals, calculating an expected value of a harmonic based on the complex power at a first time and a plurality of values of the complex power, where the values of the complex power are measured at times before the first time, and comparing the expected value and a measured value of the harmonic.