Electrical Power Systems

82 Electrical Power Systems
\ p = m
L
NM
HG
I - - HG KJ HG
L 2pI
sin 2( wt - f) + sin 2 wt - f - + sin 2 wt -f- NM HG 3 KJ HG
2pI
2p
p = msin( wt – f)cos( wt – f) + sin wt-f- cos wt-f-
HG 3KJ
3
I + - - KJ O QP 4p
4p
sin wt f cos wt f
3
3
2
\ p = 0 ...(4.11)
The sum of quadrature components results in
L
NM
2pI
2p
q = msin( wt – f)sin( wt– f) + sin wt-f- sin wt-f-
HG 3 KJ 3
+ - - HG I - - KJ
HG I
KJO QP 4p
4p
sin wt f sin wt f
3
3
\ q = 3
...(4.12)
2 m
Therefore, resultant armature mmf or stator mmf becomes
s = p + q = 3
2 m ...(4.13)
We therefore conclude that the resultant mmf has a constant amplitude perpendicular to
line pq.
ield alignment for synchronous generator is shown in ig. 4.2 using space vectors to
represent the different fields.
ig. 4.2: Phasor/vector diagram for non-salient pole synchronous generator.
HG
4p
3
IO KJ QP I KJ
I KJ