TB close
signal
TB closed
Yes
No
TB closed
Voltage
on main
busbar
No
Yes
Trip GB
Synchronise
TB
Syn-
chronised
No
Yes
TB closed
Close TB
Voltage on
emergency
busbar
No
Yes
GB closed
No
Yes
TB sync.
enabled
No
Yes
Sync. timer
expired
No
Yes
TB closed
No
Yes
Alarm
Alarm
1.
TB closed:
After getting the TB close signal,
the controller checks whether the tie breaker
is closed. If the tie breaker is already closed,
the sequence stops.
2.
GB closed:
The controller checks whether
direct closing is okay (no voltage on the main
busbar, no voltage on the emergency busbar,
and the generator breaker is open).
•
If direct closing is OK, the controller closes
the tie breaker.
•
If direct closing is not OK, the controller
checks whether
Tie breaker sync. enabled
is enabled.
◦
If
Tie breaker sync. enabled
is
enabled, the controller synchronises
across the tie breaker by regulating
the emergency genset. When the
busbars are synchronised, the
controller closes the tie breaker.
◦
If
Tie breaker sync. enabled
is not
enabled, the controller trips the
generator breaker. When the
generator breaker is open, the
controller closes the tie breaker.
3.
TB closed:
The controller checks whether the
tie breaker has closed.
•
If the tie breaker has closed, the tie
breaker close sequence has been
completed successfully.
•
If the tie breaker is not closed, the
TB
closing failure
alarm is activated.
9.5.7 Tie breaker open flowchart
The following flowchart shows the sequence that the controller uses to open the emergency busbar tie breaker.
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