ABB RET670 Applications Manual page 688

Section 3
IED application
682
Table 164: Blockings without setting possibilities
Activation Type of blocking
Disconnected
transformer
(automatically reset)
No Master/More than
one Master
(automatically reset)
One transformer in a
parallel group switched
to manual control
(automatically reset)
Communication error
(COMMERR) (automatic
deblocking)
Circulating current method
Mutual blocking
When one parallel instance of voltage control TR8ATCC (90) blocks its operation, all
other TR8ATCCs (90) working in parallel with that module, shall block their operation
as well. To achieve this, the affected TR8ATCC (90) function broadcasts a mutual
block to the other group members via the horizontal communication. When mutual
block is received from any of the group members, automatic operation is blocked in the
receiving TR8ATCCs (90) that is, all units of the parallel group.
Description
Auto Block Automatic control is blocked for a transformer when
parallel control with the circulating current method is
used, and that transformer is disconnected from the
LV-busbar. (This is under the condition that the
OperHoming is selected Off for the
setting
disconnected transformer. Otherwise the transformer
will get into the state Homing). The binary input signal
DISC in TR1ATCC (90) or TR8ATCC (90) function
shall be used to supervise if the transformer LV
circuit breaker is closed or not. The outputs TRFDISC
and AUTOBLK will be activated . Blocking will be
removed when the transformer is reconnected (input
signal DISC set back to zero).
Auto Block Automatic control is blocked when parallel control
with the master-follower method is used, and the
master is disconnected from the LV-busbar. Also if
there for some reason should be a situation with
more than one master in the system, the same
blocking will occur. The binary input signal DISC in
TR1ATCC (90) or TR8ATCC (90) function shall be
used to supervise if the transformer LV circuit breaker
is closed or not. The outputs TRFDISC, MFERR and
AUTOBLK will be activated. The followers will also be
blocked by mutual blocking in this situation. Blocking
will be removed when the transformer is reconnected
(input signal DISC set back to zero).
Auto Block When the setting
automatic control will be blocked when parallel
control with the master-follower or the circulating
current method is used, and one of the transformers
in the group is switched from auto to manual. The
output AUTOBLK will be activated.
Auto block If the horizontal communication (GOOSE) for any one
of TR8ATCCs (90) in the group fails it will cause
blocking of automatic control in all TR8ATCC (90)
functions, which belong to that parallel group. This
error condition will be reset automatically when the
communication is re-established. The outputs
COMMERR and AUTOBLK will be set.
1MRK504116-UUS C
OperationAdapt is " Disabled ",
Application manual