SBO Flashcards
What are the time limitations for running an SBO Diesel at no/low load?
If run at low load for >4.5 hours, then damage to diesel may occur from build up of carbon from incomplete combustion gas carryover.
Need to run at full load for minimum of 1 hour
What are the hazards created from exteded low load SBO runs?
Incomplete combustion gas carryover into exhaust causing carbon buildup that can lead to fires
What must be performed in extended low load SBO runs are performed?
If extended low load (<2175kW) runs (>4.5 hr) occur, then must run at full load for 1 hr (ramp up over 2 minutes) to bur off carryover products.
What SBO Run characteristics classify as “Low Load”?
<2175kW, should be limited to 4.5hr or less
Conditions are cumulative (1 hr at 500kw and 2 hr at 1500kw = 3 hr at low load)
Why must Bus 61/71 be restored promptly following SBO start of SBO DG?
These supply MCC 65-1/75-1 which supply the DG Auxiliaries
Must be restored to prevent engine or building overheating due to loss of radiator fans or ventilation
What impact does placing the SBO mode switch in SBO have on Bus 61/71?
Placing SBO mode switch in SBO position will trip Bus 61/71 and subsequently loss of power on MCC 65-1/75-1.
Will the SBO Engine A/B Jacket Water Temp HiHi Trip protect diesel should a delay cause the DG to be running for excess amoutn of time?
No, this trip is bypassed when started in SBO Mode
What trips are available when started in SBO mode?
Overspeed Gen Ground Gen Diff Emerg Stop Loss of power to PLC
What provides initial cooling upon SBO start in SBO Mode and restoration of MCC power?
Radiator Holding Tank (1200 gallon for 8 minutes)
What Busses do the DG’s power?
SBO DG powers 23 or 24; EDG’s power 23-1/24-1
Why must the SBO Mode switch be returned to normal and the trips reset?
Trips cannot be reset in SBO Mode, must be returned to Normal to do so
In SBO mode, most trips are bypassed except overspeed, gen ground/diff, e-stop, loss of power to PLC system
If SBO DG has been running for the past day at ~1000kW, what actions should be considered prior to shutting down the engine?
Perform a 20 minute ramp to full load, and run for at least 1 hr.
What does the “RESTORATION” feature on the DCS panel do?
Automatically adjusts SBO DG voltage and frequency for 180 seconds.
What is the minimum fuel oil level required for SBO diesel storage tank for SBO Surveillance?
7,700 gallons
Which SBO trips are only enabled during “NORMAL” mode?
Engine Lube Oil Pressure Lo Lo Engine Jacket Water Pressure Lo Lo Crankcase pressure Hi Jacket Water Temp Hi Hi Phase Overcurrent Neutral Overvoltage Loss of Excitation Negative Sequence Reverse Power
