PF Correction Savings???

[StephenSDH]

I have a customer who had a company (http://www.correctioncontrols.com/) come to their plant and claim they can reduce their KW consumption by over 6%. According to my customer they actually hooked up equipment to a machine to show him it works(I have a feeling it was just KVA reducing instead of KW reduction) There are NO incentives/fines by the power company for bad PF. My understanding of power factor correction is that it will only save you money on line losses(I^2R), and you generally do it because of fines, reduce equipment size, or reduce voltage drop. From my calculations the customer might be lucky to save 1 percent on their electric bill if the whole plant was PF corrected at the inductive loads. The company doesn't come out and say the are installing capacitors on the equipment they call them "SR Control System". I believe it is just capacitors with some magic beans tossed in. I have the feeling it is a Fly-by-night company. Before I put my foot in my mouth by telling the customer this, I wanted to check to see if anyone can vouch for a dramatic KW reduction by clipping a power correction device to to a load. Below are my calculations of a sample KVA reduction savings. Thanks ahead of time!

-Steve

Generic 3 Phase Power Savings Calculator

Voltage 480 V
Conductor Impedance 0.0265 ohm/1000ft (500 MCM)
Sets of Conductors 2 Sets (Common for 800A Service)
Feeder Distance 500 feet
Conductor Resistance 0.006625 3 Sets of 500MCM Copper
Power Factor 0.75
Current 600 A


Apparent Power 498.24 KVA
Real Power 373.68 KW
Reactive Power 329.55 KVAR

Current 600 A
Real Current 450 A
Reactive Current 396.8 A

Power Loss(I^2*R*3Ph) 7.155 KW (@ Noncorrected PF)
Power Loss(I(real)^2*R*3Ph) 4.0246875 KW (@ PF == 1)
Maximum Power Savings 3.1303125 KW
Percentage Power Savings 0.84% Percentage Savings

 

[charlie b]

Feel free to tell your customer every reason you told us. There are many similar products out there that make similar claims, and none are true. None are lies, mind you, because the statements are very carefully and cleverly worded. But if a facility does not pay a premium for having a low power factor, then power factor correction will not save them money. Also, power factor correction can have, at best, a second order impact on KW usage. Any statement to the contrary goes against the laws of physics.

 

[StephenSDH]

Thanks

Thanks

Thanks Charlie B I didn't see how this would be feasible. I don't know how people can make a career out of stuff like this. Must be hard to sleep at night.

Anyone else with thoughts please let me know.

Thanks, Steve

 

[Besoeker]

Totally agree with Stephens calculations and Charlie's comment.
Another scam, I think.
Maybe not as outrageous as some.

 

[Jraef]

Your link has an error in it, they use .net instead of .com

From reading their limited information, they seem to be adding a non-saturable reactor to the caps, essentially making a crude line filter, similar to what you see in some Power Line Conditioners. They then go on to claim that because they are reducing harmonics, THAT is where the reduction in kW is coming from. So in a way, there is a tiny tiny kernel of truth to that statement (as there usually is in these kinds of websites).

BUT, being that they cannot possibly know what your system harmonics are to start with, adding an un-tuned filter has questionable value even from that standpoint. These guys are, in my opinion, just stepping up the rhetoric game a little over the capacitor only guys. The net benefit, beyond a little line conditioning, is still questionable at best, misleading at face value and bordering on fraudulent at worst (although I will not make that a definitive statement, because they probably have better lawyers).

In other words, the fishy smell you noticed is still coming from some old fish, but they have piled some fresh fish on top..

 

[weressl]

I have a customer who had a company (http://www.correctioncontrols.com/) come to their plant and claim they can reduce their KW consumption by over 6%. According to my customer they actually hooked up equipment to a machine to show him it works(I have a feeling it was just KVA reducing instead of KW reduction) There are NO incentives/fines by the power company for bad PF. My understanding of power factor correction is that it will only save you money on line losses(I^2R), and you generally do it because of fines, reduce equipment size, or reduce voltage drop. From my calculations the customer might be lucky to save 1 percent on their electric bill if the whole plant was PF corrected at the inductive loads. The company doesn't come out and say the are installing capacitors on the equipment they call them "SR Control System". I believe it is just capacitors with some magic beans tossed in. I have the feeling it is a Fly-by-night company. Before I put my foot in my mouth by telling the customer this, I wanted to check to see if anyone can vouch for a dramatic KW reduction by clipping a power correction device to to a load. Below are my calculations of a sample KVA reduction savings. Thanks ahead of time!

-Steve

Generic 3 Phase Power Savings Calculator

Voltage 480 V
Conductor Impedance 0.0265 ohm/1000ft (500 MCM)
Sets of Conductors 2 Sets (Common for 800A Service)
Feeder Distance 500 feet
Conductor Resistance 0.006625 3 Sets of 500MCM Copper
Power Factor 0.75
Current 600 A


Apparent Power 498.24 KVA
Real Power 373.68 KW
Reactive Power 329.55 KVAR

Current 600 A
Real Current 450 A
Reactive Current 396.8 A

Power Loss(I^2*R*3Ph) 7.155 KW (@ Noncorrected PF)
Power Loss(I(real)^2*R*3Ph) 4.0246875 KW (@ PF == 1)
Maximum Power Savings 3.1303125 KW
Percentage Power Savings 0.84% Percentage Savings

To sum it up: there are Statistics, there are Damned Lies and there are Electric Power Saving Devices.