ABB Relion REC670 Applications Manual page 322

Section 13
Control
Total Block: Prevents any tap changer operation independently of the control mode
(automatic as well as manual).
Setting parameters for blocking that can be set in TR1ATCC or TR8ATCC under general
settings in PST/local HMI are listed in table 33.
Table 33:
Setting
OCBk
(automatically
reset)
OVPartBk
(automatically
reset)
UVPartBk
(automatically
reset)
UVBk
(automatically
reset)
Table continues on next page
316
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 or TR8ATCC will be
preset value
temporarily totally blocked. The outputs IBLK and
TOTBLK or AUTOBLK will be activated depending on
the actual parameter setting.
If the busbar voltage U (not the compensated load
B
point voltage UVL) exceeds
alarm will be initiated or further URAISE 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
Umin < U
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 UHIGH will be
activated as long as the voltage is above
If the busbar voltage U (not the compensated load
B
point voltage U ) is between
L
figure151), an alarm will be initiated or further
ULOWER commands will be blocked. The output
ULOW will be activated.
If the busbar voltage U 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
UBLK and TOTBLK or AUTOBLK will be activated
depending on the actual parameter setting.
1MRK 511 358-UEN A
Umax (see figure 151), an
Umax . The FSD
<
B
Umax .
Ublock and Umin (see
Ublock this
Application manual