ABB RELION 620 Series Technical Manual page 743

1MAC504801-IB E
620 series ANSI
Technical Manual
building blocks instead of fixed shots gives enhanced flexibility, allowing multiple and
adaptive sequences.
Each CBB is identical. The Shot number CBB_ setting defines at which point in the
autoreclose 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
autoreclose 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 autoreclose function can perform up to five autoreclose shots or cycles.
Section 9
Control functions
737