Under excitation limiter arid its role in preventing excessive synchronousgenerator stator end-core heating

The process of synchronous generator stator end-region heating in the under -excited condition is investigated using a thermal model based on nux densi ties consideration. The parameters of the model are identified using the Le ast-Square Method and from which the SER steady-state and transient thermal responses are determined. A new SER heating limit is derived and used for the design of the Under Excitation Limiter. The proposed method makes a mor e effective use of the generator capability to absorb reactive power withou t causing instability, SER over-heating, and serious system over-voltage pr oblems.