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, said method comprising:

• 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 the harmonic based on the complex power at a first time and a plurality of values of the complex power, wherein the values of the complex power are measured at times before the first time;
• comparing the expected value and a measured value of the harmonic;
• and
• generating an indication of a stator ground fault from the comparison.

A system for detecting stator ground faults in a generator, said system comprising:

• a microprocessor-based relay configured to:
• receive a neutral voltage signal from a neutral point of a stator;
• receive a plurality of terminal voltage and current signals from the stator;
• derive a magnitude of a harmonic component from the neutral voltage signal;
• derive a total complex power from the terminal voltage and current signals;
• calculate an expected value of the harmonic based on the complex power at a first time and a plurality of values of the complex power, wherein the values of the complex power are measured at times before the first time;
• and
• compare the expected value and a measured value of the harmonic.