Power plants and induistrial plants usually do not have a power factor of 1. Thi

Question

Power plants and induistrial plants usually do not have a power factor of 1. This is due in large to the numerous induction motors, transformers ect... Obviously the closer to 1 one the more effieicnt the process becomes. I have never heard of a large scale power factor of one. Is there any examples, or is achieving that imppossible on large scale? Power plants and induistrial plants usually do not have a power factor of 1. This is due in large to the numerous induction motors, transformers ect... Obviously the closer to 1 one the more effieicnt the process becomes. I have never heard of a large scale power factor of one. Is there any examples, or is achieving that imppossible on large scale?

Explanation / Answer

It's typically just not done. It takes an extrodinary amount of effort to get the power factor up to just 1.00 when it's likely to never happen. Consider the fact that its impossible to just cancel out capacitance and inductance entirely: if your transmitting power along power lines you have the line on a pole hanging above the ground. Air is between them. Ta da! You have a capacitor voltage is entirely along the pole, zero voltage on the ground and an air dielectric; you gain negative complex impedance from that (and it IS true). That means you need inductive reactance at the transmission point to cancel the capactive reactance from transmission itself. Even if the inductance of the wires themselves don't cancel it out, this will easily be enough to draw a "perfect" power factor down to say 0.98 or 0.97. Also consider the fact that the higher the power factor is the greater the costs to transmit the power to the load (the current increases as the power factor goes up). I know that guidelines typically require the power factor to be greater than 0.9 and if you get to 0.95 you'll be fine. There's likely more reasons as to why its difficult to get the power factor to one but consider you have to KEEP it there (these components do not last forever, your capacitor bank will eventually have to be replaced) and in industrial situations you're dealing with transformers, generators, conductors... more difficult circuit elements whose impedance is not as ideal as you'd believe when you're doing introductory circuit analysis. A good question though.

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