Handbook of Electrical Engineering

SYNCHRONOUS GENERATORS AND MOTORS 65

Figure 3.1 Phasor diagram of a two-axis salient pole generator.

Ra= 0. 002

Xd= 2. 5 Xq= 0. 9

X′d= 0. 18 X′q=Xq

Xd′′= 0. 1 X′′q= 0. 15

3.4 The Derived Reactances

The derived reactances were described in sub-section 3.2 in relation to their effect on armature
reaction. They are derived from the actual winding reactances by the standard equations, for example
References 8 and 9.

Direct axis:

Xd=Xa+Xmd (3.1)

X′d=Xa+

XmdXf

Xmd+Xf

Xa+Xf (3.2)

X′′d=Xa+

XmdXfXkd

XmdXf+XmdXkd+XfXkd

(3.3)

Xa+

XfXkd

Xf+Xkd