Section Review Flashcards
State the service flows in the gas turbine area
Fuel gas, instrument air, potable water, river water, hydrogen, nitrogen, CO2, service air
State why a turbine has an over speed trip
To prevent damage to the turbine and generator in case of failure of the other safeguards.
For the following problems state the causes and any corrective action required. Also state the results if corrective action is not taken.
A. Lube oil temp is slowly trending down.
B. Lube oil temp is slowly trending up.
A. Corrective action- Too many fans are on or control valve is open also you should see excessive bearing vibration, check other bearings, check lube oil temp in field, ccw flow/temp, and ccw valve position.
B. Corrective action- turn on fin fans and close control valve. Causes- hi bearing vibration, bearing to burn up, check other bearings, line oil temp, ccw flow/temp, and similar equipment.
State the function of the following equipment in the closed cooling water system.
A. Fin fans
B. Ccw circulation pumps
A. Fin fans pull air across finned tubes to cool the water
B. Circulate the cooling water through the cooling water header
State the equipment that is cooled by the CCW system.
Lube oil coolers, sample coolers, air coolers, flame detectors, turbine support legs, and hydrogen coolers
What do we use for make up on the CCW system?
Polished water glycol mix, can use river water as back up.
Describe how the nitrogen pad is controlled.
By a regulator
State the normal level of the CCW surge tank
75-80%
we run 10-15%
State the normal CCW pressure
60-70psi
Describe the purpose of the auto/smart on the CCW pumps.
Low pressure will start the pumps in auto
The CCW pumps are cavitating discuss cause and effects of this problem.
Cause- loss of suction or water is vaporizing inside pump casing.
Effect- This damages the impeller.
Describe actions you would take if a fin fan breaks its belt.
Red tag the switchgear, enter work order, locate correct belt, sign on master, and change the belt. Test before walking away to ensure it isn’t vibrating or an alignment issue
Describe your actions if you get a hi temp alarm on the inboard bearing on the HP boiler feed pump and the control valve is at 100%
Check for proper oil flow, check the CCW system isn’t leaking and working properly, turn on more fin fans
Describe the function of each of the following gas turbine lube oil system equipment
A. Lube oil accumulator
B. Surge tank
C. Auxiliary surge tank
Lube oil accumulator- absorbs the shock or surge of oil durning start up/ shutdown of pumps.
Surge tank- 500 gallon tank used to reduce surge and receive oil from #2 bearing.
Aux surge tank- 250 gallon tank interconnected to the surge tank, reduces surge and receives oil from #3 bearing.
State why the following items on the lube oil system should be checked on a routine round.
Reservoir level and temp
Oil spills and leaks
Filter differential
Oil presser and temp
Pump switch positions
Cooling water and valve positions
Reservoir level and temp- check for proper level and temp
Oil spills or leaks- nothing is leaking or draining oil.
Filter differential- make sure filters aren’t plugged
Oil pressure and temp- it’s at normal operating temp and pressure
Pump switch positions- make sure they’ll start in emergencies.
Cooling water valve position- make sure the ccw operating properly
State what action you would take on a low lube oil level alarm.
Add more oil from 8001 and check for leaks.
State what effect a high oil temp would have and what you would need to do to correct the oil temp.
Bearings will burn up. Make sure ccw valve is open, turn on fin fans
State what effect a high filter differential will have and what you would need to do to correct the problem.
Low oil pressure due to plugged filters. Switch over to other filters and replace the plugged ones.
State the source of the 90# steam for fire protection and how it is activated.
LP superheater suction of HRU
Snuffing steam located on wall outside load compartment
Name the two primary hazards associated with the gas turbine fire protection system.
CO2- suffocation
90# steam- thermal burn
Who must be notified any time a portion of the fire protection system is taken out of service
Fire and security
State the function of the fallowing valves associated with the GT fuel gas system.
A. Auto gas vent valves
B. Manual vent valve
C. Control valve
D. Fuel gas block valve
A. Vents durning start up shutdown
B. Depressurize the header when shutting down
C. Controls gas to burners
D. Blocks FG header
State why the fuel gas valve to the GT should always be closed when the turbine is not running.
To prevent FG from entering the system and causing a fire or explosion.
State the consequences of low fuel gas header pressure
Can’t start the turbine and you’ll loose load on turbines running.
State the type of water used for the inlet air wash.
Polished water
State when hearing protection is required when inside or around starting packing and why?
Earplugs for less then 85 decibels
Double for above 105 decibels
State the reasons for using the compressor wash while the turbine is online
It cleans the first couple row of blades from debris that goes into the GT inlet filter. It also adds a few extra megawatts making the turbine more efficient.
State the purpose of the block limit valves on the fuel gas header
Shut off fuel gas in the event of a fire, explosion, or leak.
State the hazards associated with the fuel gas and distillate
Fuel gas is very flammable and distillate contains benzene
Describe how the LP and HP steam evaporator levels are controlled.
Level is controlled by level control valves. Steam flashes out the top of the drums. Keep the tubes filled with water
State the normal control range for the fallowing LP and HP steam evaporator perimeters.
A. Pressure
B. Level
C. Conductivity
Pressure- 90# and 1550#
Level- LP/HP 0 or -1 inches of water
Conductivity- LP 20-40 HP 40-50
Describe your reaction if you heard a loud hissing noise but couldn’t see any leaks.
Leave the area the same way you entered it. Get a broom stick or inferred camera to locate HP leak.
The gas turbine is at full load and all operations are normal, the LP drum level starts dropping and the level control valve is wide open. State your action to find the problem.
Check the pump suction strainer DP, verify control valve position, check blowdown flow, intermittent blowdown valve stuck open, level transmitter is lying, kick on second pump.
State the function of the following pieces of equipment associated with the HRU duct burners.
Ignition transformer
Flame scanner
Color camera/monitors
Ignition transformers- ignition source
Flame scanners- detects flame
Color cameras/monitors- shows flame status
State the following operating parameters:
High pressure drum PH and phosphate
Low pressure drum conductivity
Boiler feed water PH and dissolved O2
High pressure drum
PH 9.2-9.8
Phosphate 4-6
Low pressure drum
Conductivity- less than 100
Boiler feed water
PH 9.2-9.6
Dissolved O2 less than 10
State the hazard of hydrogen
Explosion
State the hazard of CO2
Suffocation
State why the hydrogen purity in the generator is so important
95-98% purity to ensure a non explosive atmosphere and for more cooling capacity
State the hazards of cross tying any flows in the generator gas supply headed
It’s extremely important that oxygen does not mix with hydrogen. It could cause an explosion
Explain why the seal Oil pressure runs higher than the hydrogen pressure.
It keeps the hydrogen from escaping through the seals at the need of the generator motor
State the reason why it is a good idea to check the hydrogen bank pressure each time you make a round.
To catch a loss of hydrogen pressure early! Swap trailers if necessary
List the three bus identification numbers, generator, and transformer numbers.
Bus 81,82,83
GT 81,82,83
T 81,82,83
State the purpose of the O breaker on each 15kv bus
Tie line breaker that connects the 15kv bus to the transformer
List three hazards involved with the operation of the 15kv switchgear.
Arch flash, shock, electrical explosion
List the ppe required for operating any 15kv switchgear.
Flash suit, hood with shield, safety glasses, flash gloves, boots, hearing protection, leg wraps
How many techs are required when operating any 15kv switchgear?
2
Why is it necessary to call power dispatch before operating any 15kv switchgear?
So he can adjust load and distribute power to each unit
What is the phone number of the power dispatcher
2575
Describe the purpose and operation of each of the fallowing pumps as they pertain to the seal oil system.
Main line oil pump
Aux seal oil pump
Emergency seal oil pump
Main line oil pump- supplies seal oil through the seal oil regulator durning normal operation.
Aux seal oil pump- AC back up pump for seal oil when the turbine is down.
Emergency seal oil pump- DC back up for seal oil when AC pump isn’t working.
Describe the hazards associated with the loss of generator seal oil.
Hydrogen can leak out through the generator seals causing a fire/explosion
State the normal control range for the seal oil differential pressure.
Set diff is 5-10 psi
