Main Generator and Auxiliaries Flashcards
The Main Generator and its supports systems are the main link between the nuclear reactor and the high voltage transmission lines.
Volts? Hetz? RPM?
-Produces 22,000 Volts at 60 Hertz
-1800Rpm
-Power is delivered to the 230KV transmission system
-Most of our in-plant loads are normally off the 22kv systems via the Unit Aux Transformer
(Supplies the 4kV Buses 2 and 4)
Major Components of the Main Generator?
- Generator itself
- Generator Gas System (Hydrogen)
- H2 Seal Oil System
- Excitation System (Exciter) (Voltage Regulator)
Flow of energy
- Nuclear Energy (Reactor)
- Thermal Energy (Reactor and S/Gs)
- Mechanical Energy (Turbine)
- Electrical Energy (Main Generator)
Main Generator purpose?
-Converts energy from the reactor to electricity
Hydrogen system pupose?
-Cools the main generator
Seal Oil System purpose?
- Provides oil to seal the rotor ends of the main generator, preventing H2 leakage.
Excitation system purpose?
Control Power supply?
- Excites the main generator AC field on the rotor
- 125VDC station battery (DP-A)
Generator is cooled by Hydrogen, why? where does the heat absorbed by the H go?
- Hydrogen is unutilized because of its heat transfer ability and low molecular weight, which results in lower windage losses. (friction)
- Heat is transferred to Service Water by 4 heat exchangers located within the generator casing.
What does the Generator Gas system do?
- Provides a means for putting H2 in or taking H2 out of the generator using CO2 as a scavenging medium.
- Maintains the gas pressure in the generator at 71-75psig.
Seal oil pumps power supplies?
- Air side- MCC-4
- Air side backup MCC-C
- Hydrogen side MCC-3
- Seal Oil Backup pump MCC-20 (Lube oil reservoir)
FCV-4421
Pressure regulator valve
- Maintains Air side seal oil ~12psi above H2 pressure.(MIN 3psi)
- H2 is normally at about 71-75psi
FCV-4420
Backup reagulator valve
- Auto opens when air side pressure drops to 8psi above hydrogen pressure.
- Allows oil from either the main turbine shaft oil pump, or the Seal oil backup pump(AC)(Top of lube oil reservoir)
Air side backup pump (DC) turns on when?
-Oil pressure at the seal drops to 5psi above hydrogen pressure.
Seal oil back up pump auto starts when?
-8psig bearing oil pressure, supplies with turning gear pump
FCV-4423 and 4422
Pressure equalizing valve (Hydrogen side)
-Maintains the H2 side seal oil pressure equal to the pressure of the air side seal oil pressure. (Both on the seal oil skid)
Defoaming tanks, what do they do? and location?
- Defoaming tanks is what the Hydrogen side seal oil drains to before returning to the seal oil skid.
- They help remove hydrogen entrapped in the oil.
- located on the bottom side of the generator on both ends.
H2 side seal oil tank
Location, too high, too low
- Located on seal oil skid
- Too high a level, float valve opens and oil is drained to suction of air side pump
- Too low, a float valve opens and oil is delivered to tank from discharge of air side pump
Seal oil temperature should be maintained between what temperatures? Also the air side and hydrogen side oil tempts should be maintained within?
- 100-120F
- Within 2F of each other
Important pressures for seal oil skid:
12psig, 8psig, 5psig
- 12psig- The pressure maintained above H2 pressure by the air side oil pump (or DC backup pump) (Normal)
- 8psig- Seal oil pressure maintained above H2 pressure by Turbine Lube Oil system
- 5psig- Auto Start of the DC air seal oil backup pump
