In a 3-phase ac power transmission system using synchronous generator
1
The steady-state power limits of both round rotor and salient pole machines are reached at θ = π/2 of their respective power angle characteristics.
2
The steady-state power limit of round rotor machines occurs at a much smaller angle θ as compared to that of salient pole machine power angle characteristics.
3
The steady-state power limit of salient pole machines occurs at smaller angle θ as compared to that of round rotor machine power angle characteristics.
4
The transient state power limits of synchronous generators do not depend on initial load just before the large change in load or on 3-phase fault.