PMR Science Chapter 8 Generation of Electricity
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This document discusses how electricity is generated and distributed. It explains that generators in power stations convert mechanical energy (from steam, water, gas, or nuclear power) into electrical energy. The electricity is then stepped up to high voltages for transmission over power lines before being stepped down for distribution to homes and businesses. Transformers are used to adjust voltages for transmission and distribution. The document also provides an overview of how electricity is distributed to homes and wired within a home for safe use.
PMR Science Chapter 8 Generation of Electricity
- 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.
- 4. National Electrical Fossil fuel Grid Energy Network Heat Generator Consumers energy Steam Steam turbine
- 6. Supply Chain of Water High High Water Potential Reservoir Position Energy High Pass Generator Rotation Kinetic through Energy Turbines National Grid Consumers Network
- 10. Diesel Generator
- 11. Diesel Generator Diesel Rotation Generator Small Small Town / Village Current
- 12. Diesel generator
- 15. Gas turbine generator Compressor Air Gas chamber Mix with • Filter Natural gas • Compress Gas expand CO2 + H2O Ignited by Combustion produced Spark Plugs chamber Rotation Generator Electrical National Grid energy Network
- 17. Nuclear Power Plant Uranium Nuclear Nuclear Heat energy Plutonium reactor fission Rotate Generator Steam Boiler turbines Electrical National Grid Consumers energy Network
- 22. 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
- 23. Transformers are used to change the voltage of alternating current. A basic transformer consists of two sets of insulated coil windings on opposite sides of a soft coil. The core is constructed of many layers of thin iron called laminations.
- 24. Structure of transformer More coils – Higher voltage - Brighter light bulb
- 25. b. The primary coil is the wire coil that connected to the input voltage. c. The secondary coil is the wire coil that connected to the electrical load ( output voltage).
- 26. The output voltage produced in the secondary coil depends on a. the input voltage b. The number of turns of the primary coil and secondary coil.
- 30. Calculation
- 31. Electricity Transmission and Distribution System
- 32. Electricity Transmission and Distribution System Power 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)
- 33. Electricity Transmission and Distribution System
- 34. Transmission over a long distance High voltage Low current Reduce power loss
- 35. Electricity Transmission and Distribution System
- 36. Electricity Transmission and Distribution System
- 37. 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
- 38. Electricity Transmission and Distribution System
- 39. Electrical Supply and Wiring Systems at Home
- 40. Electrical Supply and Wiring Systems at Home Main fuse Electric meter Main Switch Lighting and Circuit Fuse box power circuits breaker
- 41. Wiring System at Home Live Wire (Brown) Neutral Wire (Blue) 240V Live Wire Electrical Appliances Neutral Wire
- 42. Earth Wire Safety device Direct excess current to an underground copper plate
- 43. 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
- 44. 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
- 45. Distribution Lines of Electricity Single Phase Three phase Residential Energy from Low Voltage High Voltage Industrial Area Area (240V) Substations
- 48. 3-pin Plug
- 50. 2-pin Plug
- 51. Electric power Measure of the amount of electrical energy used per unit time Unit: Watt 1 Watt = 1 Joule per second
- 52. Oven = 800 Watt Voltage supplied = 240V Current = ?
- 53. Cost of Electricity Cost of Electricity = kW x Hour x Price per unit
- 54. Fuse and Earth Wire
- 55. Rating : 1A, 2A, 5A, 10A, 13A Fuse Gets heated up and melts When the current flowing through it is higher than its rating
- 56. Determination of Fuse Rating Voltage Power Current Fuse Rating 240V 120W 240V 600W
- 57. Fuse Prevents current exceeding its rating from flowing through the cable and wires in the household circuits.
- 58. Earth Wire Low resistance Connects the metal casings of electrical appliances Directly to the ground.