Abstract: The excitation system is most important measure to ensure the generator normal operation and the power grid stable operation. Taking the singlemachine infinite bus power system as example, the influences of synchronous generator excitation system on the static stability and the transient stability of the power grid were studied; the relation between the type and the parameters of the excitation system and the critical fault clearing time of the electric power system was obtained by calculation, which has certain significance for enhancing the power grid stability.

Key words: excitation system, transient stability, static stability, synchronous generator, influence analysis