Table 10.6 Shaft generator breaker (SGB) blackout close flowchart
SGB blackout
close
Blackout
present
No
Yes
No blackout
close
Auto close
enabled
No
Yes
No blackout
close
Close SGB
SGB closed
No
Yes
SGB closed
SG
V&Hz
OK
No
Yes
No blackout
close
Alarm
Other
recovery
failed
No
Yes
No blackout
close
1. SGB blackout close: The shaft generator breaker (SGB) blackout close
command comes from the blackout close sequence.
2. Blackout present: The controller checks that the blackout close conditions are
present:
• There must be a blackout.
• The other blackout recovery options on the main busbar have failed (that is,
recovery by genset connection, and auto close of the bus tie breaker). Note
that the emergency genset is not included in the blackout recovery options.
• Auto close must be Enabled (that is, Configure > Parameters > Local power
management > Blackout > Blackout close > Enable SG blackout close). If
Enable SG blackout close is Not enabled, the breaker does not close
automatically.
• The shaft generator voltage and frequency from the shaft generator must be
within the allowed range.
3. Close SGB: The controller activates the output to close the breaker.
4. SGB closed: The controller checks whether the SGB has closed.
• If the SGB has closed, the SGB blackout close sequence has been completed
successfully.
• If the SGB has not closed, an SGB close failure alarm is activated.
Manual blackout close
During a blackout, the operator can manually close the shaft generator breaker by pushing the push button Close breaker
on
the display unit if there are no gensets available that can solve the blackout, and Blackout close > Enabled SG blackout close is Not
enabled.
10.3.5 Shaft generator breaker trip flowchart
The controller automatically trips the shaft generator breaker (SGB) for this alarm action:
• Trip shaft generator breaker
The controller does not require the shaft generator breaker open conditions to be met for a breaker trip. Similarly, the breaker is not
de-loaded for a trip.
DESIGNER'S HANDBOOK 4189340911K UK Page 360 of 521
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