
Flexible AC Transmission Systems 37-11
DC circuit dynamics is described by (37.11). e initial value of the DC voltage depends on the struc-
ture
o
f
t
he
c
onverter.
I
t
i
s
d
etermined
i
n
s
uch
a
w
ay
t
hat
t
he
d
evice
w
ith
m
p
= 1 operates in a capacitive
a
rea—the converter output voltage is higher than the network voltage.
d
dt
u C i
u
R
C
′
= −
′ ′
+
′
′
dc B pdc
dc
ω
(37.11)
e balance equation for the real power is given by
′ ′
=
′ ′
+
′ ′
( )
u i u i u i
dc pdc pd pd pq pq
3
(
37.12)
e
i
nuence
o
f
t
he
c
onverter
o
peration
o
n
t
he
s
mall
D
C
c
apacitor
i
s
d
escribed
u
sing
t
he
D
C
c
urrent
s
ource as shown by
′
=
′
+
′
( )
i k d i k d i
pdc p pd pd p pq pq
3
(37.13)
Finally, the state ...