ABSTRACT
However, since most synchronous machines operate nearly exclusively under balanced sinusoidal conditions, it is important that this important operating mode now be examined in some detail. Since the d–q components of voltage and current become simple constants in the steady-state it is useful to distinguish between the cases where transient or steady-state conditions are implied. The reactive power corresponding to any operating point can be determined as the out-of-phase component of current multiplied by the terminal voltage. The concept of rotating vectors on a d–q plane has already been shown to be a powerful tool for analysis of three-phase networks. It was demonstrated that the phase voltages form a balanced sinusoidal three-phase set and when the rotor of the machine rotates synchronously with this voltage vector, then both the stator voltage and the stator current vector become fixed amplitude, non-rotating vectors in the synchronously rotating reference frame.
