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Introduction to Hydro Power 15 April 2009 Monterey Institute for International Studies PowerPoint Presentation
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Introduction to Hydro Power 15 April 2009 Monterey Institute for International Studies

Introduction to Hydro Power 15 April 2009 Monterey Institute for International Studies

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Introduction to Hydro Power 15 April 2009 Monterey Institute for International Studies

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  1. Introduction toHydro Power 15 April 2009 Monterey Institute for International Studies Chris Greacen chris@palangthai.org

  2. Outline • Solar, wind, hydro – brief comparison • Hydro system overview • Some examples from Thailand and elsewhere • Site assessment • Head • Flow • Penstock length • Transmission line length • Civil works • Mechanical • Electrical

  3. Sun, Wind, & Water

  4. Micro-hydropower overview Source: Inversin, A. R. (1986). Micro-Hydropower Sourcebook.

  5. Thai Potential: 1000s of projects - 700 MW (?) Mae Kam Pong, Chiang Mai DEDE + community 40 kW $130,000 cost Sell electricity to PEA – $13,000 per year

  6. Huai Krating, Tak Power: 3 kW Head: 35 meter Flow: 20 liters/second Cost: <$6,000 (turbine - $700 baht)

  7. Kre Khi village, Tak Province 1 kW for school, clinic, church Cost: <$3,500 (turbine $250) Head: 10 meters Flow: 15 lit/sec

  8. Mae Klang Luang, Chaing Mai 200 watts $120 (turbine: $90) Installed: 2007 Head: 1.7 meters

  9. Micro-hydroelectricity: Estimating the energy available Power = 5 x height x flow height meters liters per second Watts Image Source: Inversin, A. R. (1986). Micro-Hydropower Sourcebook.

  10. Measuring height drop (head) • Site level • Pressure gauge

  11. Sight level method

  12. Hose & Pressure Gauge • Accurate and simple method. • Bubbles in hose cause errors. • Gauge must have suitable scale and be calibrated. • Use hose a measuring tape for penstock length. • Feet head = PSI x 2.31 H1

  13. Measuring Flow • Bucket Method • Float Method design flow = 50% of dry-season flow

  14. Bucket Method

  15. Float Method Flow = area x average stream velocity

  16. Civil Works – some golden rules • Think floods, landslides • Think dry-season. • Try to remove sediment • Maximize head, minimize penstock • “wire is cheaper than pipe” Image source: Inversin, A. R. (1986). Micro-Hydropower Sourcebook.

  17. Source: Inversin, A. R. (1986). Micro-Hydropower Sourcebook.

  18. Weir A Sluice allows sediment removal.

  19. Silt Basin Trash Rack Intake Head Race Penstock Weir Locating the Weir & Intake

  20. Intake directly to penstock If spring run-off sediment is not severe, the penstock may lead directly from the weir. Screened Intake Weir Penstock

  21. Side intake

  22. Trash rack: keeps the big stuff out

  23. Screens Screen mesh-size should be half the nozzle diameter. A self-cleaning screen design is best. The screen area must be relatively large. Screen Head Race Penstock Silt Basin

  24. Source: Inversin, A. R. (1986). Micro-Hydropower Sourcebook.

  25. Power Canal (Head Race) It may be less expensive to run low pressure pipe or a channel to a short penstock. Head Race 6” Penstock 4” Penstock

  26. Forebay (Silt basin) • Located before penstock • Large cross-sectional area, volume  Water velocity reduced  sediment (heavier than water but easily entrained in flow) has opportunity to drop out.

  27. Source: Inversin, A. R. (1986). Micro-Hydropower Sourcebook.

  28. Penstocks A vent prevents vacuum collapse of the penstock. Valves that close slowly prevent water hammer. Anchor block – prevents penstock from moving Vent Valve Pressure Gauge Valve Penstock Anchor Block

  29. Penstock diameter Hazen-Williams friction loss equation: headloss friction (meters) =(10.674*(F/1000)^1.85)/(CoefFlow^1.85*D^4.87)*L Where: F = flow (liters/sec) CoefFlow = 150 for PVC D = penstock diameter (mm)

  30. Penstock materials Poly vinyl chloride (PVC) Polyethylene (PE) Aluminium Steel

  31. Anchor and Thrust Blocks

  32. Source: Inversin, A. R. (1986). Micro-Hydropower Sourcebook.

  33. Locating the Powerhouse • Power house must be above flood height. • Locate powerhouse on inside of stream bends. • Use natural features for protection.

  34. Micro-hydro technology Centrifugal pump Pelton Turgo Crossflow Kaplan

  35. Turbine application http://www.tycoflowcontrol.com.au/pumping/welcome_to_pumping_and_irrigation/home4/hydro_turbines/turbine_selection (April 18, 2003)

  36. Efficiency and Flow 100% Pelton and Turgo Crossflow Propeller 50% Efficiency Francis 0% 0 0.2 0.4 0.6 0.8 1.0 Fraction of Maximum Flow

  37. Generators • Permanent magnet • Wound rotor synchronous • Induction (Asynchronous)

  38. Permanent Magnet Generator • Rotor has permanent magnets • Advantages • No brushes • Efficient • Disadvantages • Generally limited in size to several kW • field not adjustable (except ESD) • Some do AC • Some do AC and rectify to DC • Some do both

  39. Adjustable permanent magnet generator

  40. DC Alternator (automotive) • Produces rectified alternating current. • Readily available. • Easy to service. • Brushes need replacing. • A rheostat controls excitation.

  41. DC Alternator (automotive) • May be rewound for lower rpm at low head. • The field may need a battery boost to start. • Use high voltage ac output with a step-down transformer and rectifier for long transmission distance.

  42. (wound rotor) Synchronous Generator • Used in many all stand-alone applications. • Single phase up to 10 kW. • 3-phase up to >100,000 kW • Advantage: • Industrial standard • Frequency and voltage regulation • Disadvantage • Wound rotor – not tolerant to overspeed • Harder to connect to grid

  43. (wound rotor) Synchronous Generator • Most large machines use field coils to generate the magnetic field. • Rotating magnetic field induces alternating current in stator windings. Rectifier Stator Output Winding Exciter Field Winding Rotor Field Winding Exciter Winding AVR