ABB RER670 - Page 301

The line voltage drop compensation function can be turned On/Off by the setting
parameter OperationLDC. When it is enabled, the voltage U
L
will be used by the
Automatic voltage control for tap changer function,
TR1ATCC for single control
and TR8ATCC for parallel control for voltage regulation instead of U
B
. However,
TR1ATCC or TR8ATCC will still perform the following two checks:
1. The magnitude of the measured busbar voltage U
B
, shall be within the security
range, (setting Umin and Umax). If the busbar voltage falls-out of this range
the line voltage drop compensation calculations will be temporarily stopped
until the voltage U
B
comes back within the range.
2. The magnitude of the calculated voltage U
L
at the load point, can be limited
such that it is only allowed to be equal to or smaller than the magnitude of U
B
,
otherwise U
B
will be used. However, a situation where U
L
>U
B
can be caused
by a capacitive load condition, and if the wish is to allow for a situation like
that, the limitation can be removed by setting the parameter OperCapaLDC to
On.
~
Load
R
L
X
L
U
B
U
L
U
B
R
L
I
L
jX
L
I
L
Re
IE C06000487-2-en.vsd
IEC06000487 V2 EN-US
Figure 126: Vector diagram for line voltage drop compensation
The calculated load voltage U
L
is shown on the local HMI as value ULOAD under
Main menu/Test/Function status/Control/TransformerVoltageControl(ATCC,
90)/TR1ATCC:x/TR8ATCC:x.
Load voltage adjustment
SEMOD159053-118 v6
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 and parallel control
TR8ATCC:
1MRK 506 375-UEN A Section 12
Control
Railway application RER670 2.2 IEC 295
Application manual