A generator neutral ground monitoring device, said device comprising: a direct current DC sensor placed on a stator neutral ground lead of a generator, said DC sensor measuring a direct current component of a generator neutral ground current and providing a DC neutral ground signal (122, 124); an operating environment data module which provides generator operating environment data, where the operating environment data includes generator operating condition data and ambient condition data; and a monitor module including a processor and a memory, said monitor module being configured to receive the DC neutral ground signal (122, 124) and the operating environment data, analyze the DC neutral ground signal (122, 124) in consideration of the operating environment data to detect and predict faults in the generator, and issue an alarm or a diagnostic message if a fault is detected, wherein the monitor module performs fault detection and prediction using a two-part analysis, where a first part includes analyzing the DC neutral ground signal (122, 124) in consideration of the operating environment data for a current condition, and a second part includes analyzing the DC neutral ground signal (122, 124) in consideration of the operating environment data for historical conditions which represent both normal and abnormal generator operation, and wherein the monitor module includes a learning feature, where the learning feature includes self-learning by identifying correlations between the DC neutral ground signal (122, 124) and the operating environment data for both normal and abnormal generator operation, and the learning feature also includes manually-programmed learning where inspection-confirmed faults in the generator or another generator of the same type are manually correlated to the DC neutral ground signal (122, 124) and the operating environment data during a time preceding the inspection-confirmed faults, and where output of the learning feature is used in the second part of the fault detection and prediction analysis. a direct current DC sensor placed on a stator neutral ground lead of a generator, said DC sensor measuring a direct current component of a generator neutral ground current and providing a DC neutral ground signal (122, 124); an operating environment data module which provides generator operating environment data, where the operating environment data includes generator operating condition data and ambient condition data; and a monitor module including a processor and a memory, said monitor module being configured to receive the DC neutral ground signal (122, 124) and the operating environment data, analyze the DC neutral ground signal (122, 124) in consideration of the operating environment data to detect and predict faults in the generator, and issue an alarm or a diagnostic message if a fault is detected, wherein the monitor module performs fault detection and prediction using a two-part analysis, where a first part includes analyzing the DC neutral ground signal (122, 124) in consideration of the operating environment data for a current condition, and a second part includes analyzing the DC neutral ground signal (122, 124) in consideration of the operating environment data for historical conditions which represent both normal and abnormal generator operation, and wherein the monitor module includes a learning feature, where the learning feature includes self-learning by identifying correlations between the DC neutral ground signal (122, 124) and the operating environment data for both normal and abnormal generator operation, and the learning feature also includes manually-programmed learning where inspection-confirmed faults in the generator or another generator of the same type are manually correlated to the DC neutral ground signal (122, 124) and the operating environment data during a time preceding the inspection-confirmed faults, and where output of the learning feature is used in the second part of the fault detection and prediction analysis.