00:01
In this question, it is about power loss in the transmission lines.
00:04
And we use a transformer to step up the voltage.
00:08
And we want to calculate the line loss when we step up the voltage and the fraction of the input power loss and find out what difficulties encountered if we transmit the power at the generator voltage.
00:22
So to do part a, to find the line loss, and we are given the resistance per unit, is equal to 4 .5 times 10 to the power of negative 4 oms per meter and the line is 400 miles.
00:52
So the resistance is equal to 4 .5 times 10 to the negative 4, multiply with the length, which is 6 .44, times 10 to the power 5 meters.
01:05
And the resistance is 2080 oms.
01:10
Next we calculate the secondary current.
01:14
So we're using ipvp equals to isvs.
01:20
So is, the secondary current is ip times vp over vs.
01:28
So we have, so ipvp is the input power.
01:33
So we have 5 times 10 to the power negative, 10 to the power 6.
01:37
Divide by 500 kilowatts, so the current is 10 ampires and then the power loss, which is the line loss is equal to i .s square r so we have 10 square times 2090 and the power loss is 29 kilowatts.
02:01
So this is the answer for part a then for part b we want to find a fraction loss.
02:09
So the fraction is p loss divided by p input.
02:17
So this is 29 ,000 divided by 5 times 10 to the power of 6...