Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
War of the currents wikipedia , lookup
Opto-isolator wikipedia , lookup
Power engineering wikipedia , lookup
Stray voltage wikipedia , lookup
Induction motor wikipedia , lookup
Commutator (electric) wikipedia , lookup
Three-phase electric power wikipedia , lookup
History of electric power transmission wikipedia , lookup
Mains electricity wikipedia , lookup
Alternating current wikipedia , lookup
Electric motorsport wikipedia , lookup
General Electric wikipedia , lookup
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 Page 4