ABB REC670 Applications Manual page 414

Section 14
Control
408
Table 43: Blockings without setting possibilities
Activation
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 blocks its operation, all
other TR8ATCCs working in parallel with that module, shall block their operation
as well. To achieve this, the affected TR8ATCC 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 that is, all units of the parallel group.
The following conditions in any one of TR8ATCCs in the group will cause mutual
blocking when the circulating current method is used:
Type of blocking 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
setting
disconnected transformer. Otherwise the transformer
will get into the state Homing). The binary input signal
DISC in TR1ATCC or TR8ATCC 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 or TR8ATCC 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
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 in the group fails it will cause blocking
of automatic control in all TR8ATCC 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.
1MRK 511 401-UEN A
OperHoming is selected Off for the
OperationAdapt is " Off ", automatic
Bay control REC670 2.2 IEC
Application manual
SEMOD159053-285 v4