Compressed Air Flashcards
(23 cards)
What are the PAC trips?
- Loadshed (T11/21B)*
- Load Conser (Train B)*
- Motor Overload*
- Lo Lube Oil Press - < 20#
- Hi Lube Oil Temp - > 150°F
- Hi 1st Interstage Temp > 125°F
- Hi 2nd interstage temp > 125°F
- PAC Motor Lo Current
- PAC DCCS loss of control power
- Manual (Several Inputs)
*Flagged red in notes
When will the PAC Aux Lube Oil Pump start?
- On PAC start - remains running until > 42 psig.
- PAC is stopped (for 15 minutes) ***
- lo lube oil press
- loss of DCCS control power
- PA header - 97# with PAC in AUTO
Unit 1 Plant Air Compressor is supplying all compressed air needs. Unit 2 Plant Air Compressor is in STANDBY. Unit 1 PAC develops a slow OIL leak. What will occur FIRST?
- PAC Aux Lube Oil pump will auto start
What are the CAC trips?
- NESW # Low (< 6# for 5 sec) (U1) (includes on start)*
- NESW # Low (< 4.2 ΔP for 10 sec) (U2) (includes on start)*
- Overload
- LO # Low (15# with 12 sec delay)
- Low NESW # on start not greater than 15 psig (U1)
- Low NESW # on start not greater than 5.8 psid within 5 sec (U2)
- Manual
*Flagged in notes
Does the CAC trip on a Load Shed?
- No
What are the Compressed Air System header pressure actions?
- 95# - PAC Start
- 90# - CAC Start (WAR #)
- 85# PA Header Iso Valves Close
- 80# - Manual Reactor Trip
What is the correct sequence of events that automatically occur in the Control and Plant Air Systems as air pressure lowers?
A. - 95 psig at PPS-10 (20) Standby PAC starts
- 90 psig CAS wet receiver pressure CAC starts
- 85 psig at PPS-11 (21) Plant air header isolates
What can cause PAC surge?
- Discharge Valve Closed/Blocked
- Inlet Valve Throttled too far Closed
- Insufficient Inter-stage Cooling
- Opening demister valves too quickly
- Hi System Press
Where does the BACPAC tie into the Air System at and why is this important?
- Supplies air to the Plant Air ring header between the Ring Header Isolations (ie can supply CA system directly with Plant Air Ring Header isolation valves closed)
Both Units are responding to a loss of Plant Air (PA) and Control Air (CA) event.
The following conditions exist:
Both Unit’s Plant Air Compressors (PAC’s) have failed.
Both Unit’s Control Air Compressors (CAC’s) have failed.
Both Unit’s PA Header pressures are 70 psig and lowering.
Both Unit’s CA Header pressures are 80 psig and lowering.
An AEO has been dispatched to start the Back-up Plant Air Compressor (B/U PAC), per 01-OHP-4022-064-001, Control Air Malfunction.
What describes the B/U PAC ability to repressurize both Unit’s Control Air Systems under these conditions?
- C. The B/U PAC will discharge to both Unit’s Control Air Systems
If you lost NESW to CAC, will the CAC still start?
- No, it will not start
What are the reasons for cooling the air on the PAC?
- Physically reduces the necessary pipe size for the system
- Causes moisture to condense so it can be removed by moisture separators
How many running PACs are required to supply both units?
- 1 PAC can supply both units
Can one CAC supply both units CA?
- No, each CAC can only supply its own unit
Will the PAC automatically restart after a trip?
- No, The PAC will not start automatically after it has been manually shutdown or has tripped. Check for the message “Ready Auto Start”
- Must wait 2 minutes ***
What is the CAC flow path if the CAC is running??
- Inlet Air Filter
- CAC
- CAC Aftercooler
- Moisture Sep
- Wet CA Receiver
- CA Prefilters
- CA Dryers
- CA After filters
- Dry CA Receivers
- Air pressure reg valves & ctmt supply headers
Where does the PA tap into the CA system?
- Feeds downstream of the Wet CA receiver before the CA Prefilters
What happens on a Phase “A” signal with respect to CA?
- The CA CIVs will close
When will the CAC auto start?
- 90# at the Wet CA Receiver
If all the Plant Air Header isolation valves close, will the PAC still be able to feed CA?
- NO, PA feeds in upstream of PRV-10/20, so if they were to isolate along with PRV-11/21, the CAC will start to supply the CA header
If you had an air leak downsteam of PA-128 (PLANT AIR TO CONTROL AIR DRYER EQUIPMENT SHUTOFF VALVE) , what would happen?
- If pressure dropped to 95# the stby PAC would start
Will the CAC trip if there is a loss of NESW #?
- yes, it trips on loss of NESW #
When restoring power during a loss of power which train will restore the Control Air Compressor
Train A
