Systems and Components Flashcards
Three Phase Theory
For AC transmission of electricity over longer distances
Why AC
Easier + cheaper for longer distance electricity transfer
Why AC –> DC conversion
reduce power loss
Balanced 3 Phases
All shifted by 120° …But why is this ideal tho???!!
If you had 4 phases would 90° be best???
Why 3 phase
single phase (system?) to provide 3 phases needs 1 wire for each phase and 1 neutral for each f those wires
3 phase need 1 wire for each phase and a common neutral
Star Connection
Components share only one node
Something something…look at lecture slide13
Delta Connection
One component shares the nodes of the other components. Then other shit happens
Delta Connection
One component shares the nodes of the other components. Then other shit happens
No neutral points, so the phase and line voltages are the same. But the stupid root 3 thing comes up again but for current instead
“You make shitty notes, but I feel your pain” - Future Richmond
Line voltage and phase voltage are also a thing…
GOOD LUCK….Haha, nice.
Parts of Power System
Generation
Transmission
Distribution
Benefits of Centralised Grid
- Utilise cheapest way to generate electricity
- Reliable power generation
- Reserved power can still be shared in the system
Frequency change in grid
- Changes because of an imbalance of the consumers and producers
- Lower frequencies indicate a higher number of consumers
- Higher frequencies indicate a larger number of producers
Underground vs Overhead cables
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Why High voltages used for long distance transmission
The percentage power loss is lower at higher voltages
Electrical Generator
- Makes the electricity
* Produces active (normal) power, can also produce/consume reactive power. These combine to make complex power
Bus (Busbar)
• Low impedance connection between multiple electrical components
Transformers (robots in disguise!)
- Used to step the voltage up or down
- Several are often used consecutively to bring the voltage up or down by large amounts e,g. step down from 400 kV to 230 V
Switchgear
read notes
or at least try to pay attention
Substations
Are a thing…
Transmission Cables
Used to transfer electricity over long distances between generators, substations and loads
Load
Anything that consumes active power
One or collective loads
Transmission cables
underground is more reliable/durable but are more expensive because of installation and maintenance
Overhead line
made up of conductors, insulators and supporting structures
ACSR
Type of conductor usually used for power transmission Aluminium Conductor Steel Reinforced
Insulators in transmission
Support and anchor conductors
Insulate tower and ground
Normally ceramics
Modelling
Transmission lines can be modelled using steady state conditions
Magnetic coupling
Happens between any two conductor and something else…
