A.B. Hopkins Generating StationElectric Generator System

August 1 2014Test Bank of Questions Unit 2 HPA

Test Bank of Questions

Electric Generator System
HOPKINS REPOWERING PROJECT
UNIT HP2A

1.TH-HOP-16Electric Generator System

What is the purpose of the exciter?

  1. Controls final generator voltage
  2. Boosts voltage between the HP/IP and LP turbines
  3. Starts the generator
  4. Synchronizes the generator to the step-up transformer

2.TH-HOP-16Electric Generator System

How is hydrogen removed from the hydrogen-cooled generator?

  1. Released to the atmosphere
  2. Purged using carbon dioxide
  3. Purged using instrument air
  4. Flushed out with water

3.TH-HOP-16Electric Generator System

Where are the field windings located?

  1. Exciter
  2. Stator
  3. Rotor
  4. Permanent Magnet Generator

4.TH-HOP-16Electric Generator System

What is the armature also called?

  1. Field windings
  2. HRSG
  3. Rotor
  4. Stator

5.TH-HOP-16Electric Generator System

What is one advantage of hydrogen cooling over air cooling?

  1. Windage and ventilation losses are reduced because of the low density of hydrogen gas
  2. An increase in output per unit of active material due to high density of hydrogen gas
  3. Life of insulation on stator winding is increased because of lower thermal conductivity
  4. Maintenance expense is reduced because hydrogen is an oxidizing agent

6.TH-HOP-16Electric Generator System

How is the electro-magnetic field for the generator formed?

  1. AC current is passed through the rotor windings
  2. AC current is passed through the stator windings
  3. DC current is passed through the rotor windings
  4. DC current is passed through the stator windings

7.TH-HOP-16Electric Generator System

What connects the steam turbine generator to the step-up transformers?

  1. Isolated phase bus
  2. Exciter
  3. Stator coil
  4. Run transformer

8.TH-HOP-16Electric Generator System

How is generator output voltage controlled?

  1. Regulating the general protective relays
  2. Regulating the turbine rotor
  3. Regulating the isolated phases
  4. Regulating strength of the main generator field

9.TH-HOP-16Electric Generator System

What happen when the generator field breaker is closed?

  1. Output voltage drops to zero
  2. Voltage is transferred to the manual control panel
  3. Voltage automatically rises to the preset no-load voltage
  4. Voltage automatically rises from no-load to full-load

10.TH-HOP-16Electric Generator System

Where is the permanent magnetic generator located?

  1. Turbine end of the generator
  2. Outboard end of the exciter shaft
  3. Inside the stator wrapper
  4. Inside the rotor casing

11.TH-HOP-16Electric Generator System

What is the purpose of the seal oil system?

  1. Prevents hydrogen from leading from the generator
  2. Provides lubrication to the bearing seals
  3. Removes hydrogen safely from the generator
  4. Prevents air from coming in contact with CO2

12.TH-HOP-16Electric Generator System

What is one function of the generator gas system?

  1. Generates hydrogen and carbon dioxide used in the generator
  2. Safely supplies and removes hydrogen from the hydrogen-cooled generator
  3. Regulates CO2 content of cooling hydrogen
  4. Converts liquid hydrogen to gas

13.TH-HOP-16Electric Generator System

What are the safe purity levels for hydrogen in the hydrogen-cooled generator?

  1. Below 4.1% and above 74.2%
  2. Above 74.2% only
  3. Between 4.1% and 72.4%
  4. 100% only

14.TH-HOP-16Electric Generator System

Which of the following is NOT a protection provided by the voltage regulator circuits?

  1. Over-excitation protection and maximum excitation limiter
  2. Minimum excitation limiter
  3. Volts per Hertz protection and volts per Hertz limiter
  4. Amps per Hertz limiter

15.TH-HOP-16Electric Generator System

Where is the hydrogen stored at the plant?

  1. Under the ammonia tanks
  2. On the turbine deck
  3. In the hydrogen building
  4. Behind the hydrogen control panel on the pump room floor

16.TH-HOP-16Electric Generator System

In the last step of manual synchronization of the generator, you adjust the regulating valves until the associated pressure gauges read what?

  1. ± 2" H2O
  2. 5 psi
  3. 12 psi above hydrogen pressure
  4. 95% purity

17.TH-HOP-16Electric Generator System

During synchronization, the synchroscope is placed on the bus to be synchronized. Which bus is that?

  1. Isolated phase bus
  2. North or south pole bus
  3. East or west bus
  4. Minimum excitation limiter

18.TH-HOP-16Electric Generator System

When the generator is taken out of service for a short term (less than three months), what is done with the turbine?

  1. Connected to the backup generator
  2. Purged with air
  3. Shut down
  4. Left on the turning gear

19.TH-HOP-16Electric Generator System

What should be done when the generator is shut down for a long duration?

  1. Operate the turning gear and lube oil system continuously
  2. Operate the seal oil and generator gas systems several hours each month
  3. Operate the turning gear and lube oil system several hours each month
  4. Disconnect the generator shaft from the turbine

20.TH-HOP-16Electric Generator System

What does the rotor act as?

  1. Large electromagnet
  2. Container for the stator
  3. Mechanical power supply for the turbine
  4. Static starter for the generator

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