European Journal of Scientific Research - EuroJournals

A Rule-Based Fuzzy Automatic Voltage Regulator for Power System Stability 927
line to a very large network approximated by an infinite bus. The classical third order single–axis
dynamic model of the simple machine infinite bus power system shown in fig 3 has the equations as
follows [12,13]
3.1. Mechanical equations
() t = ω()
-ω
0
� δ t
(1)
ω� () t =
D
ω0
( ω()
t -ω0
) − ( Pe
( t)
− Pm
)
H
2H
(2)
The mechanical input power Pm is assumed to be constant in the excitation controller design.
This implies that the governor action is slow enough not to have any significant impact on the machine
dynamics.
3.2. Electrical generator dynamics
′
1
T ′
( )
() t = E () t − E () t
Eq f q
d 0 (3)
3.3. Electrical equations (assumed X ′ d = X q )
q () t = E′
q () t + ( X d − X ′ d ) I () t
′ f () t = K cU
() t
E′
d ()
() t Vs
sinδ
() t
t =
E d
E f
P
I
I
e
d
q
Q
() t
() t
() t
E′
q
=
X ′ ds
−V
s cosδ
t
X ′
() t ()
Vs
sinδ
=
X ′
E′
q
=
ds
ds
() t
() t V cosδ () t
s
X ′
ds
() t = X I () t
′
E ad f
() t = E′
() t − X ′ I () t
2
s
V
−
X ′
[ ( ) ( () ) ] 2
1
2
2
+ X I t
Vt q d d
d q
ds
(11)
More details of the modeling can be seen in [14]. The definitions of the parameters are as
indicated under symbols and abbreviations.
X = X + X + X
(12)
ds
ds
d
d
T
T
L
L
X ′ = X ′ + X + X
(13)
X =
X + X
s
T
L
(4)
(5)
(6)
(7)
(8)
(9)
(10)