Effects of synchronous machine saturation, circuit parameters, and control systems on transient stability

The effects of synchronous machine iron saturation, circuit parameters, and control systems on the power system transient stability phenomena are presented in this paper. Effect of saturation is considered to be very important on the power system steady-state and transient performances when it is required to calculate the power system stability characteristics accurately. For solid round rotor body synchronous machines, saturation effects are significant in both d- and q-axis, and because of this nonlinearity, the d- and q-axis magnetizing reactances are depressed to a considerable degree from their unsaturated values tinder both steady-state and transient operations. The system stability performance is also greatly influenced by the machine control system and damper circuit parameter variations.