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DG Flashcards

(59 cards)

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1
Q

What will Auto start the DG’s

A

SLAC

SIAS
LOP
AFAS
CSAS (test mode)

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2
Q

What is the rating of the DG

A

5500 kw continuous

6050 kw for 2 hours in a 24 hour period

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3
Q

How quickly must a DG start

A

At rated speed and voltage AND ready to accept load within 10 SECONDS

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4
Q

What is the ONLY direct mechanical trip of the DG

A

Overspeed butterfly valve

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5
Q

What is the ONLY automatic trip to stop the DG on loss of Control Air

A

Overspeed butterfly valve

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6
Q

What is the minimum level of the FOST

A
  • ≥71% tech spec limit
  • ≥80% admin limit
  • Based on 7 days of continuous run at 100%
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7
Q

Describe the operating characteristics of the Fuel Oil Transfer pump

A
  • Located inside FOST
  • Pumps at more than twice DG consumption rate
  • Auto runs 3.2 - 4.6’ in day tank
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8
Q

What is the minimum level in the DG Day tank

A
  • 2.75’
  • Exceeds the minimum 1 hour full load plus 10%
  • Auto makeup 3.2 - 4.6’
  • Useable capacity 1055 gallons
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9
Q

How much fuel does the DG use at full load

A

6.55 gpm

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10
Q

Describe the DG main governor

A
  • Electro-mechanical governor
  • Driven from drive end Left Cam shaft
  • Electric portion is internally redundant
  • Mechanical backup controls speed at 608 RPM and is
    slower than electrical
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11
Q

How does the DG governor control engine speed

A
  • moves linkages which operate Jerk pump metering
    pistons to control fuel entering cylinders
  • Bimba vlv is an air piston that shortens to engage
    linkage
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12
Q

How is a DG “Slow Start” accomplished

A
  • Slow start takes longer, >10 seconds
  • Controlled by Governor bleed port
  • Bleed port opens allowing governor oil to recirc to
    reservoir
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13
Q

What is a DG Incomplete Sequence Trip

A
  • 2 Types of incomplete sequence trips
  • Failure to crank - DG does not reach >280rpm
  • Failure to Run - DG does not reach >540 rpm
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14
Q

How does the DG Overspeed Governor work

A
  • Driven from Drive end Right Crank shaft
  • Mechanical governor
  • Trips at 660 RPM
  • Trip arms actuate Butterfly vlv & fuel shut off switch
  • Fuel shutoff switch ports control air to align off air
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15
Q

What does DG Jacket Water cool

A
  • Cylinder Jackets
  • Main Governor
  • Turbocharger
  • intercooler heating coil
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16
Q

How is flow directed from the Engine Driven Jacket water pump

A
  • Flow directed to thermostatic vlv to cooler or bypass
  • off to loads
  • Controls Temp. 170 ±5*F
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17
Q

How is flow directed from the Motor Driven Jacket water pump

A
  • Flow directed through heater
  • Heater slaved to pump, on when pump runs
  • Off to loads
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18
Q

What concern/ OE is there with the DG Jacket Water Heater

A
  • There is no level interlock

- Heater will be damaged if run without water

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19
Q

Describe the flow of the engine driven Lube Oil

A
  • Driven from Crankshaft
  • through pump to thermostatic vlv
  • Directed through or bypass cooler 165±5*F
  • Through Filter
  • Through Strainer
  • To bearings
  • Turbo has additional Duplex filter
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20
Q

Describe the flow of the engine driven Lube Oil

A
  • Driven from Crankshaft
  • through pump to thermostatic vlv
  • Directed through or bypass cooler 165±5*F
  • Through Filter
  • Through Strainer
  • To bearings
  • Turbo has additional Duplex filter
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21
Q

How does a low DG lube oil pressure trip work

A
  • Test Mode 1 pressure switch (3 or5) will trip
  • Emergency mode selective 2 of 4 trip (3 or 5 & 7 or 9)
  • additional trip input protects from failed sensor
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22
Q

What are the DG Turbo low oil setpoints

A

Alarm - 30 psig

Trip - 27 psig

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23
Q

What starts the DG Essential HVAC

A
  • ESFAS sequencer
  • 25 SECONDS after DG starts, starts Ess. Exh.
  • Ess. AHU slaved to exh.
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24
Q

How Long can the DG run without ESP support

Study These Flashcards
A

Unloaded - 15 minutes

Loaded - 2.6 minutes

25
How does BOP-ESFAS interact with the DG
LOP - Start in Emergency mode SIAS - Start CSAS - Start AFAS - Start
26
How does PPS-ESFAS interact with the SG
SIAS - Start in Emergency | AFAS - Start in Emergency
27
What is the basis for DG Air Receiver volume/ pressure
- Each receiver 5 consecutive starts | - 250 psig
28
What is the most likely cause of DG air dryer high refrigerant pressure
Air dryer fan/s goes out
29
What is DG turbocharger purge air
- Small amount of turbo discharge air - Flows backwards through start air header - Purge of warm air purges any combustion leakage - Prevents moisture condensing in air header
30
What is DG starting reset air
- Downstream of Starting air control vlvs - Uses small air tank with calibrated bleed port - Blocks Turbo Lo Oil Press trip to allow press to build
31
What is DG Non-Fail safe air
- Always available - Supplies both ON and OFF air - Pressurizes the trip system - If lost DG must be tripped manually with BUTTERFLY
32
What conditions must be met to start the DG any mode
- Overspeed reset - Generator Differential reset - Low engine oil press reset - Emergency stop button reset - Mode Control switch not in OFF
33
How is the LOP signal different than the other DG start signals
- LOP is locked in DG circuitry | - BOP-ESFAS signal clears after 60 seconds
34
What conditions are required for the DG output brkr to close AUTOMATICALLY
- LOP - Rated speed and votage - No 86 on Norm or Alt. brkr - Both Norm and Alt. brkrs OPEN
35
What conditions are required for the DG output brkr to close MANUALLY
- Rated Speed and Voltage - No 86 on Norm or Alt. brkr - Alt. brkr open - Sync Key ON
36
What is the concern with starting the DG from the ESFAS cabinet
- DG will start, but test trip still active - Test run trip stops fuel - When DG <280 RPM starting air applied to "start" DG - Will Drain Air Receivers
37
If the DG started from a LOP what must be done before stopping the DG
- Take DG to OVERRIDE - Normal supply brkr must be CLOSED - LOP signal clears after 60 SECONDS
38
What are the DG Emergency trips
- Overspeed - Generator Differential - Low Lube oil pressure (selective 2 of 4)
39
What occurs when the DG is placed in Override
- Speed control restored - Volt. control restored - Speed & Volt. mode control selectable Droop/ISoch - Disables DGSS hard start signal - Reestablish DG brkr trips: - Overcurrent - Neutral Voltage - Negative Sequence
40
What DG brkr trips are restored in Override
- Overcurrent - Neutral Voltage - Negative Sequence
41
What is the purpose of the DG 5 minute cooldown
Test Emergency run Solenoids | Test the pneumatic integrity of the trip system
42
What are the DG Test Run Trips
- High Jacket Water Temp - Low Turbo lube oil pressure - Turbo Thrust brng failure - Main and outboard brng high temp - Connecting rod brng high temp - Crankcase high press. - Incomplete Sequence - Under frequency - Negative Sequence - Reverse Power - Loss of Field - Neutral Overvoltage - Generator Overcurrent
43
What parameters must be closely monitored if the DG starts in Emergency during a cooldown cycle
- Jacket water Temp - Crankcase Press - Turbo Lube Oil press.
44
What Section is used to place the DG in STBY
6. 9 - Normal run | 6. 1 - After maintenance or action that could lockin LOP
45
How is DG real and reactive load adjusted when paralleled
Volt adj - Adjusts MVARS | Speed adj. - Adjusts Load
46
How does the DG respond to a loss of Class Control Power
- DG trips | - Output brkr remains closed
47
How does the DG respond to a loss of Non-Class Control Power
- DG trips if NOT in emergency mode - Prevents start from CR - Will Still Auto start for Emergency runs
48
How does the DG respond to a Loss of Control Air
- No effect during engine startup - Prevent any trips except overspeed from stopping DG - Trips will trip brkr, but engine keeps running
49
How can a DG be forced to stop
- Main governor load limit to minimum - Hold fuel control handle OFF until DG stops - Trip Overspeed butterfly - Close Day tank outlet (slowest due to fuel in lines)
50
Which DG trips require repair prior to restart
- Turbo Thrust Brng Failure - Main/ outboard brng high Temp - Connecting rod brng high temp
51
What is required for DG Loss of Voltage Start (LOVS) relays to be OPERABLE
Mode: 1-3 Mode: 4 when DG required 4 Channels Loss of voltage and Degraded voltage functions auto-innitiation per DG shall be OPERABLE 1 LOVS ch/DG INOPERABLE: 1 HOUR -Place Channel in Bypass or Trip 2 LOVS ch/DG INOPERABLE: 1 HOUR - DG Inop - OR place 1 channel bypass 1 channel trip >2 LOVS ch/DG INOPERABLE: 1 HOUR - Restore all but 2
52
What is required for AC Sources - Operating to be OPERABLE
Mode: 1-4 2 Offsite power sources, 2 DG's, and both load sequencers Shall be OPERABLE 1 Offsite inop: 1 HOUR - SR for operable side 1 DG inop: 1 HOUR - SR for Operable side 3 or more AC sources inop: 1 Hour - Restore AC sources
53
What is required for AC Sources - Shutdown to be OPERABLE
Mode: 5-6 during fuel moves 1 offsite to required buses and 1 DG for required buses Shall be OPERABLE 1 offsite inop: IMMEDIATELY - Declare effected features INOP - OR stop core alts, stop fuel moves, Stop + rx, restore power 1 DG inop: IMMEDIATELY - stop core alts, stop fuel moves, Stop + rx, restore power
54
What is required for DG Fuel Oil, Lube Oil, and Starting Air to be OPERABLE
Mode: When DG is required ``` Minimum for LCO: Enter individual LCO (all >1 hour) FOST - ≥80% Lube Oil - ≥2.5 inch Air Receiver - ≥230 psig Day Tank Lvl - ≥2.75 ft ``` ``` DG Inop: IMMEDIATELY FOST - <71% Lube Oil - <1 inch Air Receiver - <185 psig Day Tank Lvl - <2.75 ft ```
55
What are the DG Engine low oil setpoints
Alarm - 35 psig | Trip - 30 psig
56
What is the minimum Intake Temp when the DG is in STBY? What warms the intake in STBY?
- 105°F - Jacket Water
57
What is the Jacket Water Makeup sources?
- DW - Preferred - CT - FP (hose connection)
58
What is Jacket Water Temp maintained at while in STBY?
120 - 135°F
59
What is DG Lube Oil Temp maintained at while in STBY?
120 - 135°F
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