ABB REC670 Applications Manual page 410

Section 14
Control
404
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 40.
Table 40: Blocking settings
Setting Values (Range)
OCBk Alarm
(automatically Auto Block
reset) Auto&Man Block
OVPartBk Alarm
(automatically Auto&Man Block
reset)
UVPartBk Alarm
(automatically Auto&Man Block
reset)
UVBk Alarm
(automatically Auto Block
reset) Auto&Man Block
Table continues on next page
Description
When any one of the three HV currents exceeds the
preset value IBlock , TR1ATCC or TR8ATCC will be
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 point
B
Umax (see figure 170), an alarm
voltage UVL) exceeds
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 voltage into the range
Umax . The FSD 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 point
B
voltage U ) is between Ublock and Umin (see figure170),
L
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
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.
Bay control REC670 2.2 IEC
1MRK 511 401-UEN A
Umin < U
<
B
Umax .
Ublock this blocking
Application manual