ABB REG670 Applications Manual page 590

Section 15
Control
584
Rline
j
1
Xline Zline
j
IEC06000626 V1 EN
Figure 293: Transformer with reverse reactance regulation and no circulating
current
The voltage DU=U
-U
B L
that if j2 is slightly less than -90°, then U
U regardless of the magnitude of the transformer load current I
B
dashed line). The automatic tap change control regulates the voltage towards a set
target value, representing a voltage magnitude, without considering the phase angle.
Thus, U as well as U
B L
value.
Assume that we want to achieve that j
D = ´
U Z I
ß
0
j j
-
j 90 j j
D = ´
Ue Ze Ie
1
ß
0
j j
- = +
90
1
ß
0
j j
= - -
90
1
EQUATION1938 V1 EN
If for example cosj = 0.8 then j = arcos 0.8 = 37°. With the references in figure 293, j
will be negative (inductive load) and we get:
j = - -
- = -
0 0
( 37 ) 90
1
EQUATION1939 V1 EN
Generator protection REG670 2.2 IEC and Injection equipment REX060, REX061, REX062
I
T
*Xline has the argument j2 and it is realised
=I *Rline+j I
T T
will have approximately the same length as
L
and also the dashed line could all be said to be on the target
= -90°, then:
2
j j +
j ( )
=
ZIe
1
0
53
1MRK 502 071-UEN -
I *Rline
T
U
L
jI *Xline
T
DU
U
j
B
2
en06000626.vsd
(indicated with the
T
(Equation 277)
(Equation 278)
Application manual