Grade 9 Science - Week 8: Electricity Generation, Transmission, and Distribution

Introduction

• Welcome to the last lesson of Quarter 4 in Grade 9 Science.
• Topic: Electricity generation, transmission, and distribution.
• Learning Objective: Explain how electrical energy is generated, transmitted, and distributed.

Importance of Electricity

• Vital to modern life and industries.
• Used in homes for appliances, gadgets, lights, etc.

Electricity Generation

• Sources: Electricity is generated from various sources such as running water, wind, sunlight, nuclear reactions, and burning fossil fuels.
• Power Plants: Facilities where electricity is generated.
  • Example: Geothermal power plant uses Earth's heat.
  • Requires high temperatures (300°F - 700°F).
  • Process involves drilling wells, using steam/hot water to drive turbines, and cycling water back.

Generation and Magnetism

• Generation is achieved by turning large turbines connected to a generator.
• Electromagnetic Induction: Interaction between a changing magnetic field and a conductor to produce electric current.
  • Discovered by Michael Faraday.

Transmission and Distribution

• Transmission:
  • After generation, electricity flows through step-up transformers.
  • Voltage increased up to 756kV for long-distance travel.
• Distribution:
  • Goes through substations; voltage reduced by step-down transformers (13kV to 2kV).
  • Further reduction in pole transformers (240V to 120V).
  • Delivered to homes via service boxes and electric meters.

Consumption Calculation

• Factors:
  • Amount of electrical power consumed.
  • Duration of usage.
• Formula:
  • Energy (E) = Power (P) × Time (T)
  • E measured in kilowatt-hours.
• Sample Problem:
  • 250W refrigerator for 8 hours.
  • Conversion: 250W = 0.25kW.
  • Energy = 0.25kW × 8 hours = 2 kWh.
  • Cost = Energy × Cost per kWh.
  • Example given: 16.64 pesos.

Key Concepts

• Power Plant: Facility for electricity generation.
• Generator: Converts mechanical energy to electrical energy.
• Transmission Lines: Carry high voltage electricity over distances.
• Distribution Lines: Deliver lower voltage electricity.
• Basic Equipment:
  • Turbine: Rotating shaft with blades.
  • Generator: Converts mechanical to electrical energy.
  • Transformer: Adjusts voltage levels.
• Power Loss: Occurs due to resistance in wires during transmission.

Conclusion

• Summarized lesson on electricity generation, transmission, and distribution.
• Encourage engagement with the channel for more content.
• Acknowledgements and shout-outs to students and supporters.