ABB RET670 Applications Manual page 669

1MRK504116-UUS C
Application manual
T1
I
T1
V
B
I L
Load
V
L
en06000486_ansi.vsd
ANSI06000486 V1 EN
Figure 281: Parallel transformers with equal rated data.
In the reverse reactance method, the line voltage drop compensation is used. The
purpose is to control the voltage at a load point further out in the network. The very
same function can also be used here but with a completely different objective.
Figure 282, shows a vector diagram where the principle of reverse reactance has been
introduced for the transformers in figure 281. The transformers are here supposed to be
on the same tap position, and the busbar voltage is supposed to give a calculated
compensated value V that coincides with the target voltage VSet.
L
I =I =(I +I
T1 T2 T1
ANSI06000485 V1 EN
Figure 282: Vector diagram for two transformers regulated exactly on target voltage.
T2
I
T2
R I =R I
L T1 L T2
jX I =jX I
L T1 L T2
V
B
)/2
T2
en06000485_ansi.vsd
Section 3
IED application
663