ELECTRICAL INSTALLATION

Sub-strand 3.1: Generation, Transmission, and Distribution of Electricity  

1. Methods of Generation of Electrical Energy:
   1. Thermal Power Plants: Burn fossil fuels (coal, natural gas) to produce steam, which drives turbines connected to generators. 

Thermal power plant 

• Hydroelectric Power Plants: Use the kinetic energy of falling water to drive turbines connected to generators. 

Hydroelectric dam 

• Nuclear Power Plants: Use nuclear fission to generate heat, which produces steam to drive turbines connected to generators. 

Nuclear power plant 

• Wind Power Plants: Use wind turbines to convert wind energy into electrical energy. 

Wind turbine farm 

• Solar Power Plants: Use photovoltaic cells to convert sunlight directly into electrical energy. 

Solar power plant 

• Geothermal Power Plants: Use heat from the Earth’s interior to produce steam, which drives turbines connected to generators. 

Geothermal power plant 

• Functions of Components in the Electrical Power Transmission Network:
• Generators: Convert mechanical energy into electrical energy. 

Electrical generator 

• Transformers: Step up voltage for efficient transmission and step down voltage for distribution. 

high voltage transformer 

• Transmission Lines: Carry high-voltage electricity over long distances. 

high voltage transmission towers 

• Substations: Contain transformers, switchgear, and other equipment for voltage transformation and distribution. 

Electrical substation 

• Distribution Lines: Carry lower-voltage electricity to consumers. 

Distribution power lines 

• Circuit Breakers and Switches: Protect the system from faults and allow for isolation of sections. 

Circuit breaker panel 

• 3-Phase 4-Wire Distribution Circuit:
  • A 3-phase 4-wire system provides three phase lines and a neutral line.
  • Used for distributing power to residential and commercial consumers.
  • Phase symmetry ensures balanced loads.
  • Line-to-line voltage is higher than line-to-neutral voltage. 

3-phase 4wire distribution diagram 

• Electric Power Grid Network Model:
  • A power grid is an interconnected network of generation, transmission, and distribution systems.
  • Models can be created using diagrams, simulations, or physical representations.       Models help visualize the flow of electricity and identify critical components. 

simplified power grid diagram 

• Importance of a Grid System:
  • Ensures reliable and continuous power supply.
  • Allows for efficient distribution of electricity over large areas.
  • Enables load balancing and sharing of resources.
  • Supports economic development and industrial growth.
  • Facilitates the integration of renewable energy sources. 

Map showing a countries power grid  Sub-strand 3.2: Equipment at Consumers Intake Point  

1. Identifying Equipment at Consumers Electrical Power Intake Point:
   1. The consumer’s intake point is where the electrical supply from the distribution network enters the building.
   1. Common equipment includes: 
      1. Isolation switch (main switch)
      1. Electricity meter
      1. Circuit breakers (main circuit breaker)
      1. Cartridge fuses
      1. Consumer control unit (distribution board/consumer unit)  Earthing terminal

Electrical meter 

• Functions of Control Equipment:
  • Isolation switch (main switch):
    • Provides a means to completely disconnect the electrical supply for maintenance or emergencies.

Isolation switch 

• Electricity meter:
  • Measures the amount of electrical energy consumed.

Electricity meter 

• Circuit breakers (main circuit breaker):
  • Protect the installation from over-currents and short circuits.

Circuit breaker 

• Cartridge fuses: 

 Provide backup protection against over-currents.

Cartridge fuse 

• Consumer control unit (distribution board/consumer unit): 

 Distributes the electrical supply to individual circuits within the building.  Contains circuit breakers or fuses for each circuit.

Consumer control unit opened 

• Installing Control Equipment in the Correct Sequence:
  • The correct sequence ensures proper protection and operation.
  • Typical sequence: 

o     Isolation switch → Electricity meter → Main circuit breaker/fuses → Consumer control unit.

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