1 / 67

S u st aina b le Ene r gy

S u st aina b le Ene r gy S y st em s - Lecture 4: Electrical Power Plants, Electric Power , and Loads. D r . Carl Elks Departme n t of E lect r i c al and Compu t er Engine eri ng. Back to the Future. Alexander G. Bell.

owen-strong
Download Presentation

S u st aina b le Ene r gy

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. SustainableEnergy Systems - Lecture 4: Electrical Power Plants, Electric Power , and Loads Dr.Carl Elks Department ofElectricalandComputerEngineering

  2. Back to the Future Alexander G. Bell If Alexander Graham Bell were somehow transported to the 21st century, he would not begin to recognize the components of modern telephony – cell phones, texting, digital modulation, 4G, cell towers, PDAs, etc. – while Nickolas Tesla one of the grid’s key early architects, were zapped back to life, he would be totally familiar with the grid today. Power transformers, synchronous generators, AC, relays, switches were the major components of the grid in 1910 – as they are today. Our century-old power grid is the largest interconnected machine on Earth. It is the Ultimate Cyber- Physical System. Nickolas Tesla

  3. The Grid – It Lives In the Now The Grid is constantly adjusting generation to match demand – 24/7 • The US electric consists of more than 9,200 electric generating units with more than 1,000 GW of generating capacity connected to more than 300,000 miles of transmission lines (DOE 2011a).

  4. What isa PowerPlant? • A powerplantcomprisesof severalgeneratingunits. • Eachgeneratingunitisanintegratedsystem which consistsof severalequipmentsthatare usedinenergyconversionprocess. • Typically,generatingunitscompriseof: • Generator • TurbineorPrime Mover • Boiler,pump,coolingtower(in case ofhighpressureand • hightemperaturesteammedium) 8/19/2012

  5. HowElectricityisGenerated by conventional Methods • Electricity isgeneratedfromother energyformsto electricitythroughthe energyconversion process. • Themostcommonconversion processtogenerate electricityistoconvertmechanicalenergyusinga generator. • Thisprocessis called“Electromagneticinduction”. You learned about this from Dr. Beans lecture… • Themechanicalenergycomesfromturningtheturbine • (primemover). PrimeMover- Turbine Generator 8/19/2012

  6. EnergyConversionProcess • Typical mediumtomove the turbineishigh pressureand hightemperaturesteam. • Thesteamiscreatedfrom boiling water ina closedloop systemtoreduce impuritiesthat may affectthe turbine efficiency. • Thesource ofheat dependson fueltypes. • Heat energyis usuallymeasuredin ‘BritishThermal Unit’or ‘BTU’. Medium: High Pressure HighTempsteamOr,air Fossil-fuel (coal/NG), Nuclear, Biomass, Geothermal, Solarthermal PrimeMover-Turbine Generator Byproduct 8/19/2012

  7. ThermalPowerPlants:Operation • Sourceoffuel:coal,oilornaturalgas. • Step1: Burnthefuel toheatwater. • Step2:High temperature/highpressure steam OR air passestheturbinethatconnectstothegenerator. • Step3:Electricityisgenerated by electromagnetic Induction.Theby-productintheprocessishightemperature steam. • Electricity outputcanbe controlledby adjustingthefuelto boilwaterandgenerate steam. • Pro: Cheaptooperate,dispatchablemakesit flexibleto operate. • Con:Emission,pollution, Co2, GHG – emerging regulation for GHG. 8/19/2012 20

  8. TypesofTurbines • Steamturbines (ST) • Usesteamtoturnthe turbine • Gasturbines (GT) • Use hotairtoturnthe turbine • Combinedcyclegas turbines (CCGT) Rolls Royce’sgasturbine GE’s steam turbine 8/19/2012

  9. SteamTurbine(ST) 8/19/2012

  10. GasTurbine(GT) – Top Section Exhausted high temperature air 8/19/2012

  11. CombinedCycleGasTurbine (CCGT) 8/19/2012

  12. Coal-FiredPowerPlant Cleancoal technology, “Gasification” 8/19/2012

  13. NaturalGas/OilPowerPlant Fuel-switchingcanbe doneincase of emergency 8/19/2012

  14. HydroPowerPlants 30

  15. HydroPowerPlants:Operation • Step1:Releasethewatertoturntheturbine • Step2:Electricityisgenerated. • Electricityoutputcanbecontrolledby adjustingthevalve. • Pro:Cheap,clean,fastresponse. • Con:Difficulttoplantheoperation. 8/19/2012

  16. TheThreeGorges DaminXiling,Hubei World’slargesthydroelectricpower plantInstalledcapacity:22,500MW 32mainturbine,each with700MWcapacityplustwo50MWgenerators. 8/19/2012

  17. WindPowerPlants 8/19/2012

  18. WindTurbine:Operation Pro:Clean,freeenergy (no fuelcost) Con: High maintenancecost,cannot bedispatched unless you have storage capacity.. 8/19/2012

  19. WindPowerCurve Wind powercurve is output characteristicof windturbine. Ideal windpowercurve Actualwindpowercurve Windstatistics 8/19/2012

  20. FuelCellPowerPlants 400kWinstallation onGoogle’s main campus Dr.K.R.Sridhar,Bloomfounder andChiefExecutive Officer Missionstatement:“BloomEnergyhasdevelopedasimplerwaytopower datacenters andmissioncriticalfacilities.” Currentcustomers:Google, ebay,AT&T,walmart,FedEx,CocaCola,Adobe,etc… 8/19/2012

  21. FuelCellPowerPlants:Operation Pro:Highefficiency usinglessfuel(hydrogenorhydrocarbon,oxygen), producewater, heat,small emission. Con: Comparativelyexpensive,stillinresearchdevelopment 8/19/2012

  22. Performance Characteristics Summary – Electrical Efficiency rarely exceeds 35% for steam turbines. CHP operations – Where the heat is used for work inside the plant Increases efficiency of the turbine.

  23. Combined Heat and Power (CHP) or Co-Generation • Combined heat and power (CHP) and cogeneration are terms used interchangeably to denote the simultaneous generation of power (electricity) and usable thermal energy (heat) in a single, integrated system. • A CHP plant derives its efficiency, and hence lower costs, by recovering and utilizing the heat produced as a by-product of the electricity generation process that would normally be wasted to the environment. • The overall fuel efficiency of typical CHP installations are typically around 60%-70% as compared to 40% for conventional steam turbine only plants. • HOWEVER, the high efficiency of the plant is only valid if you use the HEAT. See next slide…

  24. Efficiency as function Power/heat ratio Typical Power Plant P/H operating Point. 70% Electrical 30% heat – Overall Efficiency is 47%

  25. AvailableTechnologies Conventionaltechnologies Renewabletechnologies Medium-highvoltagelevel Medium-highvoltage level Distributedtechnologies Low-mediumvoltagelevel 8/19/2012

  26. Use of Water in Power Generation • Fresh water is a valuable resource in most parts of the world. Where it is at all scarce, public opinion supports government policies, supported by common sense, to minimize the waste of it. • Most if not all conventionally generated power plants use thermal power (turbines of some type as the prime mover). Steam turbines are prevalent even in combined cycle plants. • Water is directly used in Hydro power generation • How much water is used for Thermal Power generation?

  27. Relationship Between Water and Energy

  28. Relationship Between Water and Energy • The use of water is significant • 59 billion gallons of seawater and 136 billion • gallons of freshwater per day (Hutson et al., • 2004). • NOTE: The power production • does not consume all of this water, it uses it for • Steam make up, cooling, etc… • Some of the water is released back • to the source as discharge This 39% is now 41% (2012) and represents the total water used By Power Plants (Coal, Nat Gas, Nuclear, CHP, Biomas, geothermal).

  29. Water use by Technology

  30. Projected Water Use

  31. Fundamentals of Electrical Generation: AC, PF, and 3-phase 8/19/2012

  32. Electrical Power: Conventional Generation This “stuff” is what we want to characterize and tie in with Dr. Bean’s lectures

  33. Outline • Fundamentalsofelectricpower • ACVoltage/Current • Power factor • Three-phasesystem

  34. A Sinusoidal Current- What comes out of the wall socket

  35. VoltageandCurrent Function • VandI insteady state aresinusoidalfunctions • with constant frequency 25 ∏/2 20 15 10 ∏/4 vt20co2 s60t  2  5 0 it5co260t s -5  -10 4  -15 -20 -25 -1/120 0 1/120 1/60 t

  36. RootMeanSquare Value RMSvaluefor a square function, RMSvaluefor a sinusoidalfunction,

  37. EffectivePhasor Representation • Define: V VmcostV  V m 2 aseffectivePhasorrepresentationin polar form Vm • SinceV , wecanwrite,V costV  m V rms V rms 2 • RectangularrepresentationofaPhasoris, VrmscosV jsinV VrmsV • This helps to addandsubtractphasors.

  38. Ideal Resistor

  39. Ideal Capacitor

  40. Ideal Conductor  10

  41. Instantaneouspower Powerfactor Complex/apparentpower Powerfactor correction COMPLEX POWER 10/6/2010

  42. InstantaneousPower vt it 2VcostV  2IcostI • Let pt= instantpowerat t absorbedby the network • Then,ptvtit • VIcosV Icos2tV I

  43. InstantaneousPowerPlot 100 ptvtit 80 60 40  it5cos260t 4  20   0 vt20cos260t   2 -20 -1/120 0 1/120 1/60 t

  44. AveragePower • Averagepoweroverone period, • T P1ptdt T 0 0 cos2tV Idt 1T 1T 1 VmImcosV Idt   T 0 2 T 0 1 V I VmIm cosV I   cos m m V I 2 VIcosV I 2 2 AfractionofthemagnitudeofVI (inrmsvalue)iscalled‘powerfactor’.

  45. PowerFactor • Powerfactorisdefinedas • PFcos • PFisalwayspositive andis between0and1!! • Terminology: I V V -Ф +Ф I Powerfactoris lagging. Powerfactoris leading.

  46. PowerFactor Angle  2 4 4 • Thephaseangle differences • betweenVandIiscalled • ‘power factorangle’: • 25 • V I 20 15 10   it5cos260t  5  4 0 -5 -10 vt20co260t s  -15 -20 2  -25 -1/120 0 1/120 1/60 t

  47. Complex/ApparentPower • Definecomplex(apparent)power(VA), • SVI* SVI* VI VIcosjVIsin V I • Thus,S=P+jQ.

  48. UndesirablePowerFactor • Undesirabletohave non-zeroreactivepower, Q, • (PF≠ 1). • Q causest-linelosseswhentransmitting power backandforthbetweenloadandgeneration. • Transformersrated inkVA, high current • magnitudeincreasethe loadingof transformer. • PF helpstoavoidadditionaltransformer capacity. 20

  49. Analogies for Reactive Power Not Useful – Unless you like foam Useful Energy Boat

  50. LoadDescription A: • A: Aloaddraws20kWat 0.707PFlagging • B: Aloadabsorbs40kW • and5kVar • C:A loadabsorbs 42.4264kVAat0.707PF • leading 45° 20kW B: 5kVar 40kW 30kW -45° C: 30kVar

More Related