Measured voltage amplitudes are all ok and equal but
the angles are strange.
Voltage unbalance protection trips immediately when
it is activated.
Earth fault protection trips immediately when it is
activated and voltage is calculated.
Voltages are connected into the measurement module, but the order
or polarity of one or all phases is incorrect.
Go to
Measurement
→
Phasors
and check the voltage vector
diagram.
When all is correctly connected the diagram should look as below
with symmetric feeding:
Settings
Table. 5.2.2. - 23. Settings of the VT scaling.
Name
Range
Step
Default
Description
Voltage meas
mode
0:3LN+U4
1:3LL+U4
2:2LL+U3+U4
-
0:3LN+U4 Voltage wiring method to the IED. Voltages are scaled according the
set voltage measurement mode.
U3 mode U0
or SS
0:NotUsed
1:U0
2:SS
-
0:NotUsed
Voltage channel U3 can be used to measure zero sequence voltage
U0 or Synchro-check voltage SS. In case these are not needed the
default setting “NotUsed” should be active. (Valid only in 2LL+U3+U4
mode)
U0 (U3)
Measured
from
0:Broken
Delta
1:Neutral
point
2:Open delta
-
0:Broken
delta
De nes how secondary voltage is scaled to primary. Does not affect to
how protection operates – only affects to displayed primary voltages.
Parameter visible when U3 channel has been set to “U0” mode.
U4 mode U0
or SS
0:NotUsed
1:U0
2:SS
-
0:NotUsed
Voltage channel U3 can be used to measure zero sequence voltage
U0 or Synchro-check voltage SS. In case these are not needed the
default setting “NotUsed” should be active.
U0 (U4)
Measured
from
0:Broken
Delta
1:Neutral
point
2:Open delta
-
0:Broken
delta
Connected U0 voltage. De nes how secondary voltage is scaled to
primary. Does not affect to how protection operates – only affects to
displayed primary voltages. Parameter visible when U3 channel has
been set to “U0” mode.
PE Voltage
measurements
0=NO PE
voltages avail.
1=PE
Voltages
calculated
2=PE
Voltages
measured
-
-
Indicates if phase to earth voltages are available or not and if the
voltages are measured from the voltage channels directly or if they are
calculated from line to line and neutral voltages.
VT primary
1…
1000000.0 V
0.1V
20000.0V
Rated primary voltage of the VT in volts.
VT secondary
0.2…400.0 V
0.1V
100.0V
Rated secondary voltage of the VT in volts.
U3 Res/SS VT
primary
1…1000000V 0.1V
20000.0V
Primary nominal voltage of connected U0 –or SS VT. (Valid only in
2LL+U3+U4 mode)
U3 Res/SS VT
secondary
0.2…400V
0.1V
100.0V
Secondary nominal voltage of connected U0 –or SS VT. (Valid only in
2LL+U3+U4 mode)
U4 Res/SS VT
primary
1…1000000V 0.1V
20000.0V
Primary nominal voltage of connected U0 –or SS VT.
U4 Res/SS VT
secondary
0.2…400V
0.1V
100.0V
Secondary nominal voltage of connected U0 –or SS VT.
AQ-T257
Instruction manual
Version: 2.00
© Arcteq Relays Ltd
28
