1. © Oxford University Press 2011 IP1.22.6 The National Grid: Power transmitted The National Grid: Power transmitted

2. © Oxford University Press 2011 IP1.22.6 The National Grid: Power transmitted The power carried by a transmission line is calculated using the following equation: Power (watts) = voltage (volts)  current (amps)

3. © Oxford University Press 2011 IP1.22.6 The National Grid: Power transmitted What is the power carried by a transmission line when the voltage is 230 V and the current is 13 A? Power = voltage  current Power = 230 V  13 A Power = 2990 W Power = 2.99 kW

4. © Oxford University Press 2011 IP1.22.6 The National Grid: Power transmitted What is the power carried by a transmission line when the voltage is 420 V and the current is 20 A? Power = voltage  current Power = 420 V  20 A Power = 8400 W Power = 8.4 kW

5. © Oxford University Press 2011 IP1.22.6 The National Grid: Power transmitted Calculate the voltage if the power is 4.3 kW and the current is 14 A. Power = voltage  current 4.3 kW = voltage  14 A = 307.1 V 4300 W 14 A

6. © Oxford University Press 2011 IP1.22.6 The National Grid: Power transmitted Calculate the current if the power is 3.6 kW and the voltage is 240 V. Power = voltage  current 3.6 kW = 240 V  current = 15 A 3600 W 240 V

7. © Oxford University Press 2011 IP1.22.6 The National Grid: Power transmitted Calculate the current if the power is 5.2 kW and the voltage is 400 V. Power = voltage  current 5.2 kW = 400 V  current = 13 A 5200 W 400 V