Abstract: Abstract:The characteristics of large gassteam combinedcycle generator and its influence on stator grounding fault protection were introduced. A complete large gassteam combinedcycle generator stator single phase grounding fault protection scheme was proposed. In the scheme, the shortcoming of previous large gassteam combinedcycle generator stator grounding fault protection scheme was overcome. The scheme was applied widely on many domestic and abroad 390MW level large gassteam combinedcycle generator units, and favorable effects were obtained.

Key words: Keywords:large gassteam combinedcycle generator, generator stator grounding fault protection, static frequency converter, grounding transformer