ABB Relion 670 Series Applications Manual page 371

1MRK 511 401-UUS F
IEC06000488 V2 EN-US
Figure 176: Inverse time characteristic for TR1ATCC (90) and TR8ATCC (90)
The second time delay,
direction as the first command). It can have a definite or inverse time characteristic according to
the setting
the similar formulas as for the first time delay, but the
Line voltage drop
The purpose with the line voltage drop compensation is to control the voltage, not at the power
transformer low voltage side, but at a point closer to the load point.
Figure 177
at the LV busbar and voltage V
resistance and reactance from the station busbar to the load point are R
between the busbar voltage and the current, is j. If all these parameters are known V
obtained by simple vector calculation.
Values for R
connected to the LV busbar, an equivalent impedance should be calculated and given as a
parameter setting.
The line voltage drop compensation function can be turned
parameter
control for tap changer function, TR1ATCC (90) for single control and TR8ATCC (90) for parallel
control for voltage regulation instead of V
perform the following two checks:
1. The magnitude of the measured busbar voltageV
Vmin and Vmax ). If the busbar voltage falls-out of this range the line voltage drop
compensation calculations will be temporarily stopped until the voltage V
the range.
2. The magnitude of the calculated voltage V
allowed to be equal to or smaller than the magnitude of V
However, a situation where V
Bay control REC670
Application manual
t1=180
t1=150
t1=120
t1=90
t1=60
t1=30
t2 , will be used for consecutive commands (commands in the same
t2Use (Constant/Inverse). Inverse time characteristic for the second time delay follows
shows the vector diagram for a line modelled as a series impedance with the voltage V
at the load center. The load current on the line is I
L
and X are given as settings in primary system ohms. If more than one line is
L L
OperationLDC . When it is enabled, the voltage V
L
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IEC06000488_2_en.vsd
t2 setting is used instead of t1 .
. However, TR1ATCC (90) or TR8ATCC (90) will still
B
, shall be within the security range, (setting
B
at the load point, can be limited such that it is only
L
>V can be caused by a capacitive load condition, and if the wish
B
, the line
L
and X . The angle
L L
Enabled / Disabled by the setting
will be used by the Automatic voltage
L
comes back within
B
, otherwise V will be used.
B B
Section 14
Control
SEMOD159053-105 v6
B
can be
L
365