Main Generation Flashcards
How does Main Generator system produce power & where does it go when it does produce ?
.Mechanical power to electrical power
.provide power to switchyard
.provide power to non-class systems
.provide power to excitation system(DC voltage induced to rotor)
What is the sequence of components in Main Generating system include ?
.Main Generator
.Isolated phase busses
.Main transformer bank (24kv->525kv)
.Tie Lines to switchyard
.Unit Aux. Transformer(24kv->13.8kv)
Major components of Main Generator ?
.Generator casing
.Stator
.Rotor
.Collector
What is included in the Generating casing?
.Stator Frame
.End Shields
.Excitation Dome
.Lower Frame Extension
What is inside the Stator frame & what does it do for cooling ?
.Stator Windings
.Stator Core
.Rotor
.Provides multiple paths for cooling Hydrogen Gas
What do End Shields do?
Used to support weight of rotor and contain Hydrogen gas inside the casing by using shaft seals
Where is the Excitation Dome ? And what does it contain?
Mounted on stator frame, containing Hydrogen Tubes and Coolers
How does power exit the generator casing?
Through the high voltage bushings mounted in the lower frame extension.
What cools High Voltage bushings in Lower Frame Extension ?
Stator Cooling Water (CE)
What is purpose of Stator ?
Generate voltage and current supply to main transformer & Unit Aux. Transformer (via isophase bus)
What is the Stator Core?
Contains insulated slots for armature bars to go through
What is the stator made of?
3 separate insulated copper bars wrapped in a ring through a laminated core.
What cools the stator windings?
Stator Cooling Water (CE)
What is the purpose of rotor ??
Produces magnetic flux to cut armature windings, creating voltage & current
How does the rotor operate ?
Windings are held together by retaining rings & DC voltage is induced to create magnetic field
What cools Field Windings on Rotor ?
Hydrogen gas flowing over bars through casing by fans installed on each end of generator
What is purpose of the Collector?
Applies DC voltage to rotor inducing rotating magnetic field
How is DC power induced into rotor ?
By slip rings & carbon brushes, through collectors carbon brushes to rotor slip rings
How is the Collector cooled ?
By mounted fan circulating air in Collector housing & through cooler with Normal chilled water
What’re isophase buses used for ?
Conducts power from Main Generator to Main Transformer & Aux. Transformer
How do isophase busses operate ?
The 3 phases from generator are isolated from each other. Insulated conductor in water/dust tight enclosure
What cools the Isophase busses ?
Forced air from Isophase Bus Duct Cooling System (CE)
How many bushings are there & what’re they called on Main Transformer?
High voltage bushing->switch yard (525kv)
Low Voltage Bushing->primary windings (24kv)
Neutral Bushing ->grounded
What’re the primary and secondary windings for in main transformer?
.Primary is 24kv from generator
.Secondary is 525kv out transformer to the switchyard
What cools the air,THAT cools the Isophase busses ?
Turbine cooling water
What does main transformer bank consist?
Three Oil Filled, Single phase Transformers
What are manually operated disconnects for ?
For isolation of the Motor Operated Disconnect for maintenance
Where are the primary windings connected to on main transformer ?
Directly connects Main Transformer to Main Generator (via Isophase bus)
What’re the breakers used for on the output breakers in the SRP switchyard ?
For synchronization to the grid and protection of equipment
What is the Constant Oil Pressure System do for the transformers ?
Maintains atmospheric pressure on oil and seals it from atmosphere
What is the Dehydrating Breather for & how do you know when to change it ?
Uses silica gel to remove moisture from air going into bladder & turns from orange to green when ready to be changed
How does Liquid Level Detector work?
Factory calibrated at 25C=77F , gauge will adjust when temp. fluctuates. High & Low levels will alarm control room
What does a Mechanical Pressure relief device do?
Spring loaded valve that relieves pressure when it gets to high in COPS reservoir
How do you know if Mechanical Pressure relief device popped open ?
Yellow or red flag up or oil is around transformer
What does the Electronic Temperature Monitor do for the transformers?
Monitors winding temps. & controls operation of cooling fan banks
How and when, will the Sudden Fault Pressure Monitor trip the Main Transformer ?
It will trip when 2/3 of the sensors sense a pressure surge
What is in the control panel for on the Main Transformer ?
Alarm annunciators, switches for cooling banks and cabinet heaters
What does the Motor Operated Disconnect Switch allow ?
Allows Main Generator to be isolated from grid for maintenance ; allows for generators breakers to be closed and still keep generator offline
What do the Main Generator breakers provide?
Ability to synchronize, connect, and disconnect power from grid ;Uses electrical protection trips for faults for Main Generator or power grid
Where are motor operated disconnects operated from?
Usually control room, but may be operated locally
Where are Main Generators breakers operated from ?
Control room
When disconnect Generator from Grid what must be done prior ?
.Reactor reduced to 20% power
.transfer power from S01&S02
—>S03&S04
.reactor & turbine trip which causes a reverse power,which trips 525kv breakers
Where is motor operated disconnect located ?
SRP switchyard
What maintained pressure of oil in Unit Aux. Transformer & how many windings does it have ?
A nitrogen blanket prevents oxygen and air and it’s maintained by nitrogen cylinder; one primary winding of 24kv, two secondary windings of 13.8kv
What kind of bushings are used on Unit Aux. Transformer ?
Two oil filled neutral bushings for grounding
Where are isolation points for the Unit Aux. Transformer ?
Primary windings directly connected to transformer; secondary windings connected to S01& S02 buses
What’re two phases of cooling for Unit Aux. Transformer ?
Setpoint is 70C , NO oil pumps
Phase 1:Natural Circ. Of oil
Natural Circ. Of air
Phase 2: Natural Circ.of oil
Forced air with all fans running
Describe sequence events for main generator sequence startup ?
Bring turbine up to speed,flash field by applying voltage to rotor, energizes main transformer first stage cooling fans and oil pumps
Describe what would happen on a loss of Main Generation system ?
Load rejection , fast bus transfer will happen if Main Generator trips
How does Excitation system (MB) interface with MA system ?
Provides DC voltage to the rotor for field excitation & provides trip signals to Generator trip logic
How does 13.8kv(NA) system interface with Generator system (MA)?
MA system provides power to NA system & NA system provides interlocks for MA system for “coast down trip”
What does 480vac (NG) system interface with MA system ?
NG system provides power to cooling fans of Main Transformer
Where do space heaters for MA system receive there operating power from ?
480 Non class-MCC via 120vac distribution panel
How does control power (NK) interface with MA system ?
Control power(NK) goes to main transformer and Unit Aux. Transformer Annunciator panel & control cabinets
How does Generator Hydrogen (GH) interface with MA system ?
System provides hydrogen to generator casing for cooling of rotor windings and maintains its purity
How does Lube Oil system interface with Generation system (MA)?
Provides lubrication/lift to rotor bearings & sends vibration signals to MA system
How does Main turbine interface with Main Generator (MA)system ?
.provides mechanical power to generator rotor
.send valve position signals to generator trip logic
.generator system sends signals to turbine grip logic
How does reactor coolant(RC) system interface with Generation system (MA) ?
MA system provides interlocks to RC system for RCP trip logic during “coast down trip “
How does 120VAC (NN) interface with MA system ?
NN provides instrument power to MA system control cabinets
How does OffSite power (NO) interface with MA system ?
Provides contact interlocks to MA system generator protection “coast down “ logic & offsite power of NA system provides power signals to MA system for billing metering
How does uninterruptible power (NQ) interface with MA system ?
Main generator TVMS cabinet & digital fault recorder receive power from NQ system
How does normal lighting(QA) interface with MA system ?
Sub synchronous resonance relay cabinets, receive operating power from plant QA system
How does In plant communications (QF) interface with MA system ?
Provides communication link between recorder data acquisition unit of each unit the master station and satellite synchronized clock
How does SRP 525kv switchyard interface with MA system ?
Ma system provides power to switchyard & contact interlocks to 525kv switchyard (reactor trip & generator trip )
How does Turbine Cooling water interface with MA system ?
TC cools hydrogen in main generator via hydrogen coolers in excitation dome
How does HVAC(HS) system interface with MA system ?
Provides cooling to sun synchronous resonance room that houses Main Generation control cabinets via Air Handling Unit
How will MA system respond to a loss of NK system ?
If reactor or turbine trip the MA output breakers will not trip and will need to be opened manually by control room
How will MA system react on loss of MB system ?
Main Generator will trip due to loss of excitation in rotor
How will MA system react on loss of stator cooling and Isophase bus duct cooling ?
Loss of stator cooling will trip generator
.Loss of bus duct cooling will force generator loading to be reduced due to high current
How will loss of Generator Hydrogen affect MA system ?
Will cause Main Generator load to be reduced.
How does a drop test work for Generator Hydrogen ?
See how much hydrogen pressure drops in 24 hour period
How will MA system react on loss of Lube oil system ?
Turbine trip, which will trip main Generator
How will MA system react on Turbine trip ?
Main generator trip
How will MA system be affected in loss of seal oil system ?
Requires the Generator to be unloaded and depressurized
How will MA system be affected on loss of Turbine Cooling Water (TC) ?
.Result in load reduction, possible Generator trip
.TC cools hydrogen coolers, isophase bus duct coolers, stator cooling water, lube oil system
What does excitation and regulation(MB) system do for MA system ?
It supplies excitation power to generator & controls output voltage from startup to rated power; regulates voltage at generator terminals at a setpoint based on requirements of grid or control room
How does main generator initially provided magnetic field rotation to rotor for startup ?
From a non class MCC
What’re the major equipment of excitation system ?
.power potential transformers
.Power conversion room (PCR)
.MARK Vle Balance of plant control system
.hvac& fire protection
What’re the power potential transformers for ?
Transforms 24kv from generator to 1050VAC for us by excitation system
What cools power potential transformers ?
Natural oil circulation and natural air circulation by the fins
What does Mark Vle Balance of Plant Control Module do ?
Monitor and controls all parameters of main generator field excitation
What happens if power is lost to main fan for the power bridge cooling fans ?
A automatic bus transfer will take place and take power to the second fan
What rooms are in the power conversion room ?
Control room , power room , air conditioning room
What will happen if you use radio in PCR room while cabinet is open ?
Interfere with components by radio frequency
What’re the two fire protection systems they’re used in PCR ?
VESDA fire detection-sends trouble alarm to control room
STAT-X fire suppression- PCR has canisters for suppression & must be dispersed manually by operator or fire department
What does power room contain ?
Excitation and regulation equipment, bridge rectifiers, cooling fans, AC cabinet from secondary windings of power potential transformer(1050VAC, DC cabinet out to rotor field windings
What does the air conditioning room in PCR house ?
HVAC units, current potential transformers, distribution panel
How do PCR HVAC fans operate normally ?
One hvac unit is running with two back ups, units alternate operating time
What do the high voltage bushing connect to, to transmit the electricity to the main transformers, auxiliary transformers, and excitation and regulation system
They connect by the isophase buses
