Distribution and safety of electricity

Question 1

What is AC: Alternating Current?

Answer 1

Current that flows backwards and forwards

Question 2

What is DC: Direct Current?

Answer 2

Current that flows in the same direction all the time

Question 3

Tell me the whole National Grid set up

About 5 things it goes through i guess?

Answer 3

1. Power station
2. Step-up transformer
3. National Grid System
4. Step-down transformers
5. 240v to your home or something
   volts in ur home like electricity OR SOMETHING

Question 4

What do network of pylons do?

Answer 4

Supports electrical cables needed to carry electricity around

Question 5

What are large transformers used for?

Answer 5

• Step-up/down voltages

* Used in the National Grid

Question 6

3 advantages and disadvantages of overhead wires :v

Answer 6

Advantages:
· Easy to be fixed
· Cheap
· Easy to see

Disadvantages:
· Can be hit by flying vehicles
· Dangerous
· Ruined scenery

Question 7

3 advantages and 2 (¬.¬) disadvantages of underground wires >:(

Answer 7

Advantages:
· Safer
· More space on surface
· Keep natural beauty

Disadvantages:
· Hard to repair and build
· Expensive

Question 8

Why is it important that the National Grid is able to respond quickly to changes in electricity demand?

Answer 8

A blackout may occur or powercut

Question 9

2 situations the National Grid power company would need to alter the amount of power available to the Grid?

Answer 9

· Winter time

· East Enders????

Question 10

Whats the base load in a graph meant to show?

Answer 10

The amount of power power stations need

Question 11

How does the national grid meet the rise in demand?

right before transformer page

Answer 11

Hydroelectric dams are opened

Question 12

What does a step-up transformer do?

Answer 12

Increase the voltage but decrease the current

Question 13

What does a step-down transformer do?

Answer 13

Decrease the voltage but increase the current

Question 14

Why is it important that the national grid must have transformers?

Answer 14

Increased current distributes extreme heat on the wires therefore voltage increases. Additionally, voltage is stepped down so it’s safer for use when it arrives to homes

Question 15

The page u are left seen on the book, is literally about calculations
And I mean:
· Electrical energy and power
· Units of electricity
· Cost of electricity
· Payback time

Just look over them on the book

Answer 15

Yes, Thanks :)

Question 16

If current flows in only one direction it’s called..?

Answer 16

Direct current

Question 17

If current constantly changes direction is is called…?

Answer 17

Alternating current

Question 18

Make sure u look at that DC and AC current page

Answer 18

I suppose, but I mean I might forget

Question 19

What are the 3 main wires that run through your house as part of the ring main circuit?

Answer 19

· Live wire (brown)
· Neutral wire (blue)
· Earth wire (green and yellow)

Definitions are going to be separated

Question 20

What does the live wire (brown) do?

Answer 20

· Brings in the alternating current/voltage

· Always connected to fuse or mcb (switch that turns off everything in the house sometimes)

Question 21

What does the neutral wire (blue) do?

Answer 21

· Takes the current out of your home

Question 22

What does the earth wire (green and yellow) do?

Answer 22

· Used for safety
· Stops you from getting electrocuted
· Takes electricity into the ground

Question 23

What does a fuse do?

Answer 23

· A fault in an appliance can cause the current to be too great leading wire to overheat and possibly cause fire
· Fuse designed to melt if current through circuit is too high, thereby breaking the circuit
· Fuse should be higher than normal working current

Question 24

What current does wire melt?

Answer 24

1.56

Idk it’s in booklet

Question 25

Read earth wire page

Answer 25

FF FFFFFFine

Question 26

What do miniature circuit breakers (mcb’s) do?

Answer 26

· Protect the device from high currents
· Use an electromagnet, activates if too high a current flows
· Magnet attracts a switch, breaking the electrical circuit
· Faster than fuses cuz they can be reset
· Acts faster than fuses cuz more sensitive

Question 27

What doe residual current circuit breakers (rccd’s) do?

Answer 27

· Protect the user from electrocution
· Use an electromagnet to detect difference between live and neutral wires’ current (I assume)
· If there’s a difference in current between live and neutral wires, electromagnet activates breaking the circuit