ABB REC670 Applications Manual page 422

Section 14
Control
416
~
V
L
R
ANSI06000487 V2 EN-US
Figure 172: Vector diagram for line voltage drop compensation
The calculated load voltage V
Main menu/Test/Function status/Control/TransformerVoltageControl(ATCC,90)/
TR1ATCC:x/TR8ATCC:x.
Load voltage adjustment
Due to the fact that most loads are proportional to the square of the voltage, it is
possible to provide a way to shed part of the load by decreasing the supply voltage a
couple of percent. During high load conditions, the voltage drop might be considerable
and there might be reasons to increase the supply voltage to keep up the power quality
and customer satisfaction.
It is possible to do this voltage adjustment in two different ways in Automatic voltage
control for tap changer, single control TR1ATCC (90) and parallel control TR8ATCC
(90):
1. Automatic load voltage adjustment, proportional to the load current.
2. Constant load voltage adjustment with four different preset values.
In the first case the voltage adjustment is dependent on the load and maximum voltage
adjustment should be obtained at rated load of the transformer.
In the second case, a voltage adjustment of the set point voltage can be made in four
discrete steps (positive or negative) activated with binary signals connected to
TR1ATCC (90) or TR8ATCC (90) function block inputs LVA1, LVA2, LVA3 and
LVA4. The corresponding voltage adjustment factors are given as setting parameters
LVAConst1, LVAConst2, LVAConst3 and LVAConst4. The inputs are activated with a
pulse, and the latest activation of anyone of the four inputs is valid. Activation of the
input LVARESET in TR1ATCC (90) or TR8ATCC (90) block, brings the voltage
setpoint back to Vset.
X
R
L
L
V
B
V
B
jX I
L L
Re
I
L L
ANSI06000487-2-en.vsd
is shown on the local HMI as value ULOAD under
L
1MRK 511 401-UUS A
SEMOD159053-118 v6
Bay control REC670 2.2 ANSI
Application manual