Year 1
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What is extra low voltage
24v,12v,1.5v
What is the power equation
P — Ixv
What are the 4 transmission voltages
400kv, 275kv, 132kv, 66kv Overhead lines
What are the 4 distribution voltages
11kv, 400v,230v,33kv
Name 5 renewable energy
Wind, solar, geothermal, water-tidal, biomass
What is periodic time
The time it takes to complete one full cycle
What equation do you use to work out XL (inductive reactance)
2x3.14xfxL(___ Henry’s )
How to work out impedance (z)
Square root of r2 (resistence)+ XL2 (squared)(inductive reactance)
How do you calculate periodic time
Periodic time= 1 — F ( frequency)
What equation would you use to calculate numbers in a transformer question
Np Vp Is — = — =. — Ns Vs Ip
Explain the 4 step process of coal being used to generate electricity in power stations
Burn coal > heat water into steam > pressurise the steam to turn the turbine > turbine will rotate the generator.
How does a transformer work
• Alternating voltage is applied across the primary coil • Which then produces a magnetic field that is continuously changing • This changing magnetic field cuts through the coils of the secondary coil • An alternating voltage is then induced across the secondary coil
Why is it important to make sure each load on 3 phases are balanced
Because if they are not there will be a current flow in the neutral at the supply transformer
Single phase power equation
I x v x p.f
Three phase power equation
Square roots 3 x I x v x p.f
4 x None renewable energy
Oil Nuclear Coal Natural gas
Generator definition
Converts mechanical energy into electrical energy
What is a generation voltage in kv
25kv
Name 2 main losses in a transformer
Iron losses Copper losses
What is copper loss
Energy lost through ‘heat’ generated by current It can be reduced by using good quality copper
What are 2 losses in iron loss
Eddy currents and hysteresis loss
How do you make a transformer as efficient as possible
Need core to reduce leakage flux And use laminated sheet
What are 3 types of cooling system transformer
Gas cooling transformer Air/ fan cooling transformer Oil cooling transformer
Describe the phaser diagram for voltage and current connected to a pure resistence
Voltage and current are the same