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: Blocking settings
Setting Values (Range) Description
OCBk
(automatically
reset)
Alarm
Auto Block
Auto&Man Block
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.
OVPartBk
(automatically
reset)
Alarm
Auto&Man Block
If the busbar voltage U
B
(not the compensated load
point voltage UVL) exceeds
Umax
(see figure 151), an
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
voltage into the range
Umin
< U
B
<
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
Umax
.
UVPartBk
(automatically
reset)
Alarm
Auto&Man Block
If the busbar voltage U
B
(not the compensated load
point voltage U
L
) is between
Ublock
and
Umin
(see
figure151), an alarm will be initiated or further
ULOWER commands will be blocked. The output
ULOW will be activated.
UVBk
(automatically
reset)
Alarm
Auto Block
Auto&Man Block
If the busbar voltage U
B
falls below
Ublock
this
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.
Table continues on next page
Section 13 1MRK 511 358-UEN A
Control
316
Application manual
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