Power Factor Correction Devices

[Nobodybusiness]

I did a search on the forum for PFC device but didn't see anything.

A. I have 3 AC units 2 for house and 1 for shop, 1AC is inverter based so not worried about that one.
B, I have a shop with a multitude of large lathes, millwork machines, Welders, Etc.
C. The shop isn't backed up on Solar but none the less would like to consider it for application.

I under that some of the ABB devices do/did just have a calculator and then various Capacitors it would turn on to correct the PF.

Is there benefit for residential Power Factor Correction?
If so is there a off the shelf method that can be implemented.
Not a static 1 Capacitor version but a dynamic one that will calculate and adjust on the fly?

 

[Nobodybusiness]

Anyone?

 

[zanydroid]

Most homes are not billed for bad power factor. Which is good because exporting solar makes power factor worse.

Improving power factor might potentially reduce resistive losses in your wiring and let you push feeders and service conductors harder.

SMA’s commercial inverters have power factor correction controller to use the VAr injection/removal capability of microinverters to neutralize this. This requires compatible inverters and current sensors sprinkled in strategic locations to determine the necessary shift and keep the control loop on track.

 

[Nobodybusiness]

Most homes are not billed for bad power factor. Which is good because exporting solar makes power factor worse.

Improving power factor might potentially reduce resistive losses in your wiring and let you push feeders and service conductors harder.

SMA’s commercial inverters have power factor correction controller to use the VAr injection/removal capability of microinverters to neutralize this. This requires compatible inverters and current sensors sprinkled in strategic locations to determine the necessary shift and keep the control loop on track.

Yea I do not know enough about how residential power is billed but if you are billed on total power used then any reactive power will cause that billing to increase.

I’m just curious because I’m sure my shop has some pretty unbalanced loads.

 

[zanydroid]

Yea I do not know enough about how residential power is billed but if you are billed on total power used then any reactive power will cause that billing to increase.

I think it is active power billing for most residential plans. I believe normal residences have OK power factor even with solar distorting the phasor by deleting so much active power, so it’s probably not worth them implementing power quality charges.

Maybe download the data from your POCO and see how they label it — kVA or kW.

 

[740GLE]

Are you trying to run a shop on an inverter with PV and running into issues with overloads, or low voltage due to VAR demand? Are you searching for problem for a solution?

AFAIK typical PF correction is usually fixed because it’s the simplest and cheapest solution (not the best), the grid usually doesn’t mind if you feed minimal VARs back to the system (negates any magnetizing current VAR demand of the distribution xfrmr).

If you’re looking a a variable VAR device (spinning rotational mass, or static switches device) the complexity and possible maintenance isn’t worth the headaches, let the utility manage VAR flow and maintain voltage.

Until the utilty charges me for the VARs I use I won’t be looking to add any more complexity to my residential wiring, we already have to deal with stupid arc fault breakers that are crazy expensive and have such a short life span.

 

[Nobodybusiness]

Are you trying to run a shop on an inverter with PV and running into issues with overloads, or low voltage due to VAR demand? Are you searching for problem for a solution?

No the shop is totally on Grid unless I upgrade enough to cover it.

I tried running the shop early on but was using more power and I needed to add more panels.
So instead just cut the PV to the shop.

Yes searching for a problem with a solution.
That's why I was asking if it was an issue with Residential power.

I imagine most of my shop is the only place were it would be a problem because of the equipment.

No idea if they even care or know of PF imbalances in residential.

 

[kundip]

I did a search on the forum for PFC device but didn't see anything.

A. I have 3 AC units 2 for house and 1 for shop, 1AC is inverter based so not worried about that one.
B, I have a shop with a multitude of large lathes, millwork machines, Welders, Etc.
C. The shop isn't backed up on Solar but none the less would like to consider it for application.

I under that some of the ABB devices do/did just have a calculator and then various Capacitors it would turn on to correct the PF.

Is there benefit for residential Power Factor Correction?
If so is there a off the shelf method that can be implemented.
Not a static 1 Capacitor version but a dynamic one that will calculate and adjust on the fly?

You have probably watched this:

I did a search on the forum for PFC device but didn't see anything.

A. I have 3 AC units 2 for house and 1 for shop, 1AC is inverter based so not worried about that one.
B, I have a shop with a multitude of large lathes, millwork machines, Welders, Etc.
C. The shop isn't backed up on Solar but none the less would like to consider it for application.

I under that some of the ABB devices do/did just have a calculator and then various Capacitors it would turn on to correct the PF.

Is there benefit for residential Power Factor Correction?
If so is there a off the shelf method that can be implemented.
Not a static 1 Capacitor version but a dynamic one that will calculate and adjust on the fly?

 

[kundip]

I think you are ahead of the game.
These are more a future thing & will be incorporated on all devices by mandation.
The amount of money you are talking about would be very little IMO.
When they are being mass produced they will be minimal cost per device but will have big ramifications for the grid.
It will assist the power companies a great deal & make our supply much better.

 

[DougfromdaUP]

SquareD makes automatic power factor correction devices, check for “Reactivar”
Utility power meters aren’t confused by reactance. They record watts, not va. For commercial they will do both.

 

[Nobodybusiness]

SquareD makes automatic power factor correction devices, check for “Reactivar”
Utility power meters aren’t confused by reactance. They record watts, not va. For commercial they will do both.

Thanks Doug...

 

[Shimmy]

I would avoid power factor correction unless you have a known problem. It can cause a number of unexpected issues if it isn't well matched and if you end up with a resonant frequency issue.

If you see your PF is under 0.6 or your service panel is overloaded then it is worth considering... but usually the utility will do a better job with it if it is needed.

 

[OzSolar]

Yea I do not know enough about how residential power is billed but if you are billed on total power used then any reactive power will cause that billing to increase.

I’m just curious because I’m sure my shop has some pretty unbalanced loads.

AFAIK unbalanced loads have little if anything to do with power factor so that's likely not going to be a problem.

I can't add much other than what has already been mentioned other than-

In my general experience if your power factor was really an issue the utility would be having a talk with you because they would be faced with having to invest in larger equipment in order to supply you. You'd probably be somewhere around Megawatt or larger facility with sizable dedicated pad mount transformer or even a small substation.

A lot of power factor correction devices are magic black boxes that are oversold by startup companies that come and go. Like vertical axis wind turbines that come and go. Hmnn... so do they just alternate? LOL

 

[OzSolar]

Look what YouTube suggested just now! And people try to tell me the big brother isn't watching.

Dave Gordon explains part of what's going on. He is great by way.

 

[Johno1066]

When I was much younger and studying the theory of electricity in the 1960's power factor was mostly a concern of the power suppliers and they stipulated that all high inductive lighting would require power factor correcting capacitors. So basically the supplier of the fluorescent, mercury vapor and sodium lighting had to build capacitors into their inductive chokes. So mostly the inductive loads caused the current to lag the voltage which was corrected by the added capacitance which tends to have the current lead the voltage and so ballance out to a great degree. Never seem to remember ever having a situation where there was a capactive load that needed correction but in those days the transistor was a new fangled device and digital electronics was way in the future and definitely no LED strip lights either. I do notice how the power factor changes with loads on the inverters but as I am running way under the cables current carrying capacity I do not care too much.

 

[740GLE]

AFAIK unbalanced loads have little if anything to do with power factor so that's likely not going to be a problem.

I can't add much other than what has already been mentioned other than-

In my general experience if your power factor was really an issue the utility would be having a talk with you because they would be faced with having to invest in larger equipment in order to supply you. You'd probably be somewhere around Megawatt or larger facility with sizable dedicated pad mount transformer or even a small substation.

A lot of power factor correction devices are magic black boxes that are oversold by startup companies that come and go. Like vertical axis wind turbines that come and go. Hmnn... so do they just alternate? LOL

If he has large 230v loads with poor PF and one leg heavily loaded, he may be running into low voltage issues, if he balanced some of his 120v loads between legs it might help out his voltage issues and avoid needing a service upgrade.

My 200a service is sourced via a 10kva 12kv poletop transformer, shared secondaries with my neighbor, my run is about 150 feet from the xfrmr to my meter socket. If I start having voltage issues and the utility can point to my increases load causing the issues (not one of their connectors or tree rubbing the triplex insulation clean), they can offer me a quote to upgrade my service, 25kva xfrmrs are now the minimum size of installations.

 

[Nobodybusiness]

AFAIK unbalanced loads have little if anything to do with power factor so that's likely not going to be a problem.

Unbalanced as in PF not amperage draw.

IE Having a .5 PF

My amperage draw on each leg is fine.

I just wasn’t sure if it was an issue or not.

I have Mills, Lathes and welders along with a ton of small motors running all the time.

I have 2 VFDs running my Bridgeports.

I have 3x 200 amp panels all fed from the same meter.
Now the 2 house panels are run via solar.

I didn’t know if the POCO was charging me for this imbalance or not or if I should do anything about it.

 

[Johno1066]

That AC theory video puzzles me a little, when the motor load is added to the resistant load his total current falls which puzzles me as low power factor increases the percieved current as more out of phase current is needed to get to the motor current required. A half horse motor will draw 373 watts loaded no mater the power factor although the total current in the conductors may increase and only 373 watts will be metered from the grid or inverter.

 

[OzSolar]

I didn’t know if the POCO was charging me for this imbalance or not or if I should do anything about it.

If they aren't clearly charging you for it then I don't think there are. Generally speaking, if there isn't a line item on your monthly statement dedicated to how much they are charging for how for from unity you are then they aren't in my experience. This sort of stuff tends to be highly regulated and not something that POCO is legally allowed to hide nor is is something they want to get caught hiding.