ABB RELION REX640 Technical Manual page 1532

Section 9
Control functions
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Each CBB is identical. The Shot number CBB_ setting defines at which point in the
auto-reclose sequence the CBB should be performed, that is, whether the particular
CBB is going to be the first, second, third, fourth or fifth shot.
During the initiation of a CBB, the conditions of initiation and blocking are checked.
This is done for all CBBs simultaneously. Each CBB that fulfils the initiation
conditions requests an execution.
The function also keeps track of shots already performed, that is, at which point the
auto-reclose sequence is from shot 1 to lockout. For example, if shots 1 and 2 have
already been performed, only shots 3 to 5 are allowed.
Additionally, the Enable shot jump setting gives two possibilities:
• Only such CBBs that are set for the next shot in the sequence can be accepted for
execution. For example, if the next shot in the sequence should be shot 2, a request
from CBB set for shot 3 is rejected.
• Any CBB that is set for the next shot or any of the following shots can be accepted
for execution. For example, if the next shot in the sequence should be shot 2, also
CBBs that are set for shots 3, 4 and 5 are accepted. In other words, shot 2 can be
ignored.
In case there are multiple CBBs allowed for execution, the CBB with the smallest
number is chosen. For example, if CBB2 and CBB4 request an execution, CBB2 is
allowed to execute the shot.
The auto-reclose function can perform up to five auto-reclose shots or cycles.
1MRS759142 C
REX640
Technical Manual