Power generation/ distribution
• The electricity power system: – Generation – Transmission – Distribution
330 kV or 132 kV
33 kV to 110 kV
6.6 kV to 22 kV
230 V & 400 V
Power generation/ distribution
Generation 23 kV AC
Transmission 330 or 500
kV AC
Transmission Substation 132 kV AC
Distribution 132 kV AC
Distribution Substation
33 kV Distribution
33 kV AC
Zone Substation 11 kV AC
Customers
500/ 330 kV 132 kV 33 kV 11 kV - Aluminium smelters
- Distribution companies - Major users such as steel plants
- Medium sized industry - RailCorp
- Small sized industry - Homes (via 11 kV/ 415 V transformers
Power generation/ distribution • Generation:
– Thermal: • Usually achieved by a fuel heating water to
produce steam to drive a turbogenerator • Fuel can include:
– Solar * – Geothermal * – Nuclear – Biogas (agricultural waste, manure, municipal
waste, plant material, sewage, green waste or food waste) *
– Natural gas or coal seam gas – Coal (black or brown)
* Renewable
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Power generation/ distribution
• Generation: – Sustainable:
• Solar thermal • Solar voltaic • Wind turbines • Tidal turbines
Power generation/ distribution • Transmission:
– Voltage transformed to extra high and ultra high voltages for transmission across long distances
– Transmission energy losses are lower at higher voltages (P = I2R)
– Extra High Voltage (EHV) > 300 kV – Ultra High Voltage (UHV) > 800 kV – Energy is transmitted as AC or DC:
• AC for distances up to around 500 km • DC for distances greater than 500 km (usually greater
than 1000 km) or for submarine cable transmission or asynchronous connections
Power generation/ distribution • Transmission:
– Large power generators feed into the transmission system (330 and 500 kV in NSW and Victoria)
– Energy is transmitted over transmission lines – Voltage is transformed down to sub-transmission
and distribution voltages for local distribution (132 kV in NSW) at transmission substations
Power generation/ distribution
• Transmission tower components: – Insulators and insulator strings
Ceramic
Glass
Power generation/ distribution
• Transmission tower components: – Insulators and insulator strings
Insulator String
Modern Long-rod Insulator
Power generation/ distribution • Transmission tower
components: – Conductors & conductor bundles
Aluminium Conductor Steel-Reinforced (ACSR)
All Aluminium Conductor (AAC)
500 kV Conductor Bundle
Power generation/ distribution • Transmission substation:
330 kV Feeders
Circuit Breakers
330/ 132 kV Transformers
330 kV Busbar 132 kV Busbar
132 kV Feeders
Power generation/ distribution • Protection systems:
– Billions of dollars of plant in the NSW power systems
– Assets must be protected against damage from: • Environmental stresses such as lightning, wind, trees,
fire, snow • Component failure • Man induced failures such as diggers, crains
Power generation/ distribution • Protection systems:
– The simplest protection against overload or over current is the fuse
– Fuses are used in distribution systems, domestic premises and appliances
– They are also used to protect high voltage equipment such as transformers and motors
Power generation/ distribution • Protection systems:
– Earth leakage (such as a residual current device, RCD)
– Earth fault – Overload – Inverse time overcurrent – Instantaneous overcurrent
– These protection schemes normally operate a
circuit breaker
Power generation/ distribution • The future power system?
– Energy technology? – Role of the power system