If
% Power loss = Power * Resistance / Voltage Squared
then when would % power loss = 100%? In the given example,
100% = 120W * 10 Ohm / V^2
when V = sqrt(1200V)
Hmm, that doesn't sound right. 100% power loss means no power gets to the destination, right? Does that mean no electrons will reach your house in this scenario?
Here's another one. Another poster said
P = I ^2 * R
so as the current through the transmission line increases, so does the power dissipated by the transmisstion line.
but P = V^2 / R
so the same could be said about voltage.
What is actually happening is that there are two resistances connected in series: the resistance of the transmission line (R1) and the resistance of the load (R2) (your laptop or whatever). If both resistances are equal then both dissipate the same amount of power, but if one is larger than the other, then the largest resistance will dissipate proportionally more power (I.e. R1=1ohm, R2=9ohm then R2 dissipates 90% of the power.) So the load should have as high a resistance as possible in order to get as much of the available power as possible. But if the load has a high resistance then a high voltage will be required in order to push electrons through the load.
The first equation could have been corrected by taking into account the difference between power into the system (from the power plant) and power used by the load (your laptop).
For another confusing read, check out http://en.wikipedia.org/wiki/War_of_Currents
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If % Power loss = Power * Resistance / Voltage Squared then when would % power loss = 100%? In the given example, 100% = 120W * 10 Ohm / V^2 when V = sqrt(1200V) Hmm, that doesn't sound right. 100% power loss means no power gets to the destination, right? Does that mean no electrons will reach your house in this scenario? Here's another one. Another poster said P = I ^2 * R so as the current through the transmission line increases, so does the power dissipated by the transmisstion line. but P = V^2 / R so the same could be said about voltage. What is actually happening is that there are two resistances connected in series: the resistance of the transmission line (R1) and the resistance of the load (R2) (your laptop or whatever). If both resistances are equal then both dissipate the same amount of power, but if one is larger than the other, then the largest resistance will dissipate proportionally more power (I.e. R1=1ohm, R2=9ohm then R2 dissipates 90% of the power.) So the load should have as high a resistance as possible in order to get as much of the available power as possible. But if the load has a high resistance then a high voltage will be required in order to push electrons through the load. The first equation could have been corrected by taking into account the difference between power into the system (from the power plant) and power used by the load (your laptop). For another confusing read, check out http://en.wikipedia.org/wiki/War_of_Currents