ABB Relion 670 Series Applications Manual page 360

Section 13
Control
Table 33:
Setting
OCBk
(automatically
reset)
OVPartBk
(automatically
reset)
UVPartBk
(automatically
reset)
UVBk
(automatically
reset)
Table continues on next page
354
Blocking settings
Values (Range)
Alarm
Auto Block
Auto&Man Block
Alarm
Auto&Man Block
Alarm
Auto&Man Block
Alarm
Auto Block
Auto&Man Block
Description
When any one of the three HV currents exceeds the
IBlock , TR1ATCC (90) or TR8ATCC (90) will
preset value
be temporarily totally blocked. The outputs IBLK and
TOTBLK or AUTOBLK will be activated depending on
the actual parameter setting.
If the busbar voltage V (not the compensated load
B
Vmax (see figure 164), an
point voltage UVL) exceeds
alarm will be initiated or further VRAISE commands
will be blocked. If permitted by setting in PST
configuration, Fast Step Down (FSD) of the tap
changer will be initiated in order to re-enter the
Vmin < V
voltage into the range
function is blocked when the lowest voltage tap
position is reached. The time delay for the FSD
function is separately set. The output VHIGH will be
activated as long as the voltage is above
If the busbar voltage V (not the compensated load
B
point voltage V ) is between
L
figure164), an alarm will be initiated or further
VLOWER commands will be blocked. The output VLOW
will be activated.
If the busbar voltage V falls below
B
blocking condition is active. It is recommended to
block automatic control in this situation and allow
manual control. This is because the situation normally
would correspond to a disconnected transformer and
then it should be allowed to operate the tap changer
before reconnecting the transformer. The outputs
VBLK and TOTBLK or AUTOBLK will be activated
depending on the actual parameter setting.
1MRK 511 358-UUS A
Vmax . The FSD
<
B
Vmax .
Vblock and Vmin (see
Vblock this
Application manual