Download TH-HOP-16GeneratorHopkinsTestQuestions

Test Bank of Questions
Electric Generator System
HOPKINS REPOWERING PROJECT
UNIT HP2A
A.B. Hopkins Generating Station
August 1 2014
Electric Generator System
Test Bank of Questions Unit 2 HPA
1. TH-HOP-16 Electric Generator System
What is the purpose of the exciter?
a.
b.
c.
d.
Controls final generator voltage
Boosts voltage between the HP/IP and LP turbines
Starts the generator
Synchronizes the generator to the step-up transformer
2. TH-HOP-16 Electric Generator System
How is hydrogen removed from the hydrogen-cooled generator?
a.
b.
c.
d.
Released to the atmosphere
Purged using carbon dioxide
Purged using instrument air
Flushed out with water
3. TH-HOP-16 Electric Generator System
Where are the field windings located?
a.
b.
c.
d.
Exciter
Stator
Rotor
Permanent Magnet Generator
4. TH-HOP-16 Electric Generator System
What is the armature also called?
a.
b.
c.
d.
Field windings
HRSG
Rotor
Stator
5. TH-HOP-16 Electric Generator System
What is one advantage of hydrogen cooling over air cooling?
a.
b.
c.
d.
Windage and ventilation losses are reduced because of the low density of hydrogen gas
An increase in output per unit of active material due to high density of hydrogen gas
Life of insulation on stator winding is increased because of lower thermal conductivity
Maintenance expense is reduced because hydrogen is an oxidizing agent
6. TH-HOP-16 Electric Generator System
How is the electro-magnetic field for the generator formed?
Draft
Page 1
A.B. Hopkins Generating Station
August 1 2014
a.
b.
c.
d.
Electric Generator System
Test Bank of Questions Unit 2 HPA
AC current is passed through the rotor windings
AC current is passed through the stator windings
DC current is passed through the rotor windings
DC current is passed through the stator windings
7. TH-HOP-16 Electric Generator System
What connects the steam turbine generator to the step-up transformers?
a.
b.
c.
d.
Isolated phase bus
Exciter
Stator coil
Run transformer
8. TH-HOP-16 Electric Generator System
How is generator output voltage controlled?
a.
b.
c.
d.
Regulating the general protective relays
Regulating the turbine rotor
Regulating the isolated phases
Regulating strength of the main generator field
9. TH-HOP-16 Electric Generator System
What happen when the generator field breaker is closed?
a.
b.
c.
d.
Output voltage drops to zero
Voltage is transferred to the manual control panel
Voltage automatically rises to the preset no-load voltage
Voltage automatically rises from no-load to full-load
10. TH-HOP-16 Electric Generator System
Where is the permanent magnetic generator located?
a.
b.
c.
d.
Turbine end of the generator
Outboard end of the exciter shaft
Inside the stator wrapper
Inside the rotor casing
11. TH-HOP-16 Electric Generator System
What is the purpose of the seal oil system?
a.
b.
c.
d.
Draft
Prevents hydrogen from leading from the generator
Provides lubrication to the bearing seals
Removes hydrogen safely from the generator
Prevents air from coming in contact with CO2
Page 2
A.B. Hopkins Generating Station
August 1 2014
Electric Generator System
Test Bank of Questions Unit 2 HPA
12. TH-HOP-16 Electric Generator System
What is one function of the generator gas system?
a.
b.
c.
d.
Generates hydrogen and carbon dioxide used in the generator
Safely supplies and removes hydrogen from the hydrogen-cooled generator
Regulates CO2 content of cooling hydrogen
Converts liquid hydrogen to gas
13. TH-HOP-16 Electric Generator System
What are the safe purity levels for hydrogen in the hydrogen-cooled generator?
a.
b.
c.
d.
Below 4.1% and above 74.2%
Above 74.2% only
Between 4.1% and 72.4%
100% only
14. TH-HOP-16 Electric Generator System
Which of the following is NOT a protection provided by the voltage regulator circuits?
a.
b.
c.
d.
Over-excitation protection and maximum excitation limiter
Minimum excitation limiter
Volts per Hertz protection and volts per Hertz limiter
Amps per Hertz limiter
15. TH-HOP-16 Electric Generator System
Where is the hydrogen stored at the plant?
a.
b.
c.
d.
Under the ammonia tanks
On the turbine deck
In the hydrogen building
Behind the hydrogen control panel on the pump room floor
16. TH-HOP-16 Electric Generator System
In the last step of manual synchronization of the generator, you adjust the regulating valves
until the associated pressure gauges read what?
a.
b.
c.
d.
± 2" H2O
5 psi
12 psi above hydrogen pressure
95% purity
17. TH-HOP-16 Electric Generator System
Draft
Page 3
A.B. Hopkins Generating Station
August 1 2014
Electric Generator System
Test Bank of Questions Unit 2 HPA
During synchronization, the synchroscope is placed on the bus to be synchronized. Which bus
is that?
a.
b.
c.
d.
Isolated phase bus
North or south pole bus
East or west bus
Minimum excitation limiter
18. TH-HOP-16 Electric Generator System
When the generator is taken out of service for a short term (less than three months), what is
done with the turbine?
a.
b.
c.
d.
Connected to the backup generator
Purged with air
Shut down
Left on the turning gear
19. TH-HOP-16 Electric Generator System
What should be done when the generator is shut down for a long duration?
a.
b.
c.
d.
Operate the turning gear and lube oil system continuously
Operate the seal oil and generator gas systems several hours each month
Operate the turning gear and lube oil system several hours each month
Disconnect the generator shaft from the turbine
20. TH-HOP-16 Electric Generator System
What does the rotor act as?
a.
b.
c.
d.
Draft
Large electromagnet
Container for the stator
Mechanical power supply for the turbine
Static starter for the generator
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