PMR Science Chapter 8 Generation of Electricity

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PMR Science Chapter 8 Generation of Electricity

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PMR Science Chapter 8 Generation of Electricity

  1. 1. Generation of ElectricityCHAPTER 8
  2. 2. Generator Electrical energy is produced by using a generator in the power station. Also called : Alternator or dynamo. Generators convert mechanical energy into electrical energy.
  3. 3. Thermal Generator
  4. 4. National ElectricalFossil fuel Grid Energy Network Heat Generator Consumers energy Steam Steam turbine
  5. 5. Hydroelectric Power Plant
  6. 6. Supply Chain of Water High High Water Potential Reservoir Position Energy High PassGenerator Rotation Kinetic through Energy TurbinesNational Grid ConsumersNetwork
  7. 7. Hydroelectric Generator
  8. 8. Hydroelectric Generator
  9. 9. Hydroelectric Generator
  10. 10. Diesel Generator
  11. 11. Diesel GeneratorDiesel Rotation Generator Small Small Town / Village Current
  12. 12. Diesel generator
  13. 13. Gas Turbine Generator
  14. 14. Gas turbine generator Compressor Air Gas chamber Mix with • Filter Natural gas • CompressGas expand CO2 + H2O Ignited by Combustion produced Spark Plugs chamber Rotation Generator Electrical National Grid energy Network
  15. 15. Nuclear Power Plant
  16. 16. Nuclear Power Plant Uranium Nuclear Nuclear Heat energyPlutonium reactor fission RotateGenerator Steam Boiler turbinesElectrical National Grid Consumers energy Network
  17. 17. Nuclear Power Plant
  18. 18. Alternative energy
  19. 19. Wind Turbine Generator
  20. 20. Cogeneration of energy
  21. 21. Transformers Function: To increase or decrease the voltage of an alternating current Alternating current flows in two direction  From the source of electricity  Back to the source of electricity  Generated by generators
  22. 22. Transformers are used to change the voltage ofalternating current.A basic transformer consists of two sets ofinsulated coil windings on opposite sides of a softcoil.The core is constructed of many layers of thiniron called laminations.
  23. 23. Structure of transformer More coils – Higher voltage - Brighter light bulb
  24. 24. b. The primary coil is the wire coil thatconnected to the input voltage.c. The secondary coil is the wire coil thatconnected to the electrical load ( outputvoltage).
  25. 25. The output voltage produced in the secondary coil depends ona. the input voltageb. The number of turns of the primary coil andsecondary coil.
  26. 26. Step up Transformer
  27. 27. Step Up Transformer
  28. 28. Step down Transformer
  29. 29. Calculation
  30. 30. Electricity Transmission andDistribution System
  31. 31. Electricity Transmission and Distribution SystemPower station Transformer Switch zone National Grid station (132 000 V) Network (11 000V) (132 000 V) (132 000 V) (275 kV) (500kV) Substation • City (416 V) Substation Main substation • House (240 V) (11 000 V) (33 000 V)
  32. 32. Electricity Transmission and Distribution System
  33. 33. Transmission over a long distance High voltage Low current Reduce power loss
  34. 34. Electricity Transmission andDistribution System
  35. 35. Electricity Transmission andDistribution System
  36. 36. Location of Transformer Step Up Transformer  Nearby Power Station  Before being distributed to National Grid Network Step down Transformer  Main substation  Branch substation  Heavy industries – 33kV  Small industries – 11 kV  City & Commercial – 450V  Residential area – 240V
  37. 37. Electricity Transmission andDistribution System
  38. 38. Electrical Supply and WiringSystems at Home
  39. 39. Electrical Supply and WiringSystems at Home Main fuse Electric meter Main Switch Lighting and Circuit Fuse boxpower circuits breaker
  40. 40. Wiring System at Home  Live Wire (Brown)  Neutral Wire (Blue)  240V Live Wire Electrical Appliances Neutral Wire
  41. 41. Earth Wire  Safety device  Direct excess current to an underground copper plate
  42. 42. Electric Meter and Main Fuse  Electric meter measures the amount of current supplied to the house  Main fuse – melt when excessive current flows through  Break down circuit  Safety device
  43. 43. Main Switch and Circuit Breaker Controls the electric  Cuts off the flow of energy from the mains electric current under supply to the abnormal condition appliances.  Short circuit of leakages
  44. 44. Distribution Lines of Electricity Single Phase Three phase Residential Energy fromLow Voltage High Voltage Industrial Area Area (240V) Substations
  45. 45. 3-pin Plug
  46. 46. 2-pin Plug
  47. 47. Electric power  Measure of the amount of electrical energy used per unit time  Unit: Watt  1 Watt = 1 Joule per second
  48. 48. Oven = 800 WattVoltage supplied = 240VCurrent = ?
  49. 49. Cost of ElectricityCost of Electricity = kW x Hour x Price per unit
  50. 50. Fuse and Earth Wire
  51. 51. Rating : 1A, 2A, 5A, 10A, 13A FuseGets heated up and meltsWhen the current flowingthrough it is higher than its rating
  52. 52. Determination of Fuse RatingVoltage Power Current Fuse Rating240V 120W240V 600W
  53. 53. Fuse Prevents current exceeding its rating from flowing through the cable and wires in the household circuits.
  54. 54. Earth Wire  Low resistance  Connects the metal casings of electrical appliances  Directly to the ground.

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