3 phase and Grid tie... what will happend?

[Sunking]

Why dont we see SWER in the rural areas of the lower 48?

Because there is no place in the USA with just 2 customers out away 500 miles away from the city and the general public where power is generated. We don't use public funds to do that, at least for now we are a Republic. If you want to be that much a hermit, you are on your own.

[miket]

So Alaska is not part of the USA?

[Sunking]

OK so I said it wrong. No Place in the lower 48.

.Some where Lower 48 came up and that is what I ran with. Alaska and Australia are the only two places I know of that use SWER. The reason they do has already been discussed.

[miket]

Well ad to that Canada (Saskatchewan), Brazil, New Zealand, Laos, Cambodia, Vietnam, South Africa and soon to be Mozambique.

500 miles is just ridiculous. On average they are way way shorter than that.

[miket]

I bet if you look hard enough you will find many rural places united states that could have saved money and used a swer line instead of a conventional but didnt because of regulatory issues or complete unfamiliarity.

[miket]

Back to the original topic there alre lots of places in europe with 3 phase residential. germany Norway etc. And yes they are adding them into new homes and they sell 3 phase appliances.

[Ernesto1]

utilities dont charge for VARs ?

so do the motors and appliances use more electricity? if you dont have a Correction device ? do they last less?
Thanks for the info!!

Unbalanced does not affect the bill, but you might have overlooked something.

As I said earlier 3-phase is typically used for industrial and commercial users. With those customers they typically have very large motor and non linear loads which results in low power factor. Here in the USA utilities do not charge residential customers for reactive power, only resistive or the real power because in a home you just do not have large reactive loads that a electric utility is concerned about.

However utilities do charge commercial and industrial users for reactive power. The lower the power factor (more reactive), the more the utility charges. The higher the power factor (less reactive), the less they charge. This is why large industrial users have capacitor banks to correct the power factor, it saves them large amounts of cash, and save the utility a lot of generating capacity. In other words the utilities penalize the users for low power factors. Both benefit when the power factor is closer to 1.

To take it one step further, the power factor correction devices you see marketed to residential customers is fraud because the utilities do not charge residential customers for VAR's.

[russ]

Your bill will not change whether you have a power factor correction device in use or not.

The utility would have to generate a small amount less - that is true but you are not billed for it.

References

http://www.nist.gov/pml/quantum/power_121509.cfm

1) http://www.splatco.com/tips/pwrfact/pfarticl.htm

Following the general theme of the thread (or at least part of it) my home has 3 phase power to the main panel inside the house. The heat pump has a 3 phase motor while the other loads are split between the phases. Well pump and system pressure pumps are 3 phase.

[Sunking]

so do the motors and appliances use more electricity?

It is a little technical to go into, but yes motors, inductive, capacitive, and non linear loads use more current than they measure. The extra power is unused and reflected back at the source and burned off as heat on the wiring. In AC volts x amps = VA or Volt amps, not watts as most think. There is a power factor involved and all that means is the voltage and current are not in phase with each other. In inductive circuitcs (motors) voltage leads the current, and in capacitive circuits current leads voltage. The difference in the phase angle is expressed as the Power Factor which is a number of 1 or less where 1 = 0 degree phase shift or a purely resistive circuit.

So watts in an AC circuit = volts x amps x PF, and Apparent power = Volt Amps. So for example lets say you have a refrigerator that you measure using 120 volts x 10 amps at a PF of .8. The VA = 120 volts x 10 amps = 1200 VAR's, and the power = 120 volts x 10 amps x .8 = 960 watts. So in order to run that fridge your generator must produce 1200 VAR's

OK as for residential, utilities do not charge customers for VAR's, only true power used. For commercial and industrial customers they do charge them for VAR's, they charge them a lot of money for it.

[onkelrolle]

Residential 3-phase power

I think the question is what are you talking about?

I am very familiar with European electrical architecturre as I have designed many systems for clients there. Eurpoean electrical systems are no different than what we use in the USA other than the standard residential service is 220-240 single phase service operating at 50 Hz, compared to the USA 240/120 volt single phase service.

That is how every electrical distribution service in the world is constructed. However what you just described for residential service IS NOT 3-PHASE, It is Single Phase just like it is done on every where in the world. The distribution is 3 phase, but for your residential electrical service you are only connected to 1 of the 3 phases via a transformer to step the voltage down from say 13.2 Kv to 220 volts.

So go ahead and take that picture and I will show you what is really happening.

My apologies for perhaps a slightly off-topic interjection. I live in Finland and here, like in some other european countries, the last stage of the distribution network is fed to the consumer as a 3-phase utility. Residential voltage is 230 volts between any phase and the neutral wire and 400 volts between any two phases. Obviously some power companies over here still have a product called 1-phase power but it is rarely used not being that much cheaper. Even then the feeder cable to the building is 3P+N but only one phase is metered.

Best regards, Rolf Möller, authorized electrician

[paulcheung]

It is a little technical to go into, but yes motors, inductive, capacitive, and non linear loads use more current than they measure. The extra power is unused and reflected back at the source and burned off as heat on the wiring. In AC volts x amps = VA or Volt amps, not watts as most think. There is a power factor involved and all that means is the voltage and current are not in phase with each other. In inductive circuitcs (motors) voltage leads the current, and in capacitive circuits current leads voltage. The difference in the phase angle is expressed as the Power Factor which is a number of 1 or less where 1 = 0 degree phase shift or a purely resistive circuit.

So watts in an AC circuit = volts x amps x PF, and Apparent power = Volt Amps. So for example lets say you have a refrigerator that you measure using 120 volts x 10 amps at a PF of .8. The VA = 120 volts x 10 amps = 1200 VAR's, and the power = 120 volts x 10 amps x .8 = 960 watts. So in order to run that fridge your generator must produce 1200 VAR's

OK as for residential, utilities do not charge customers for VAR's, only true power used. For commercial and industrial customers they do charge them for VAR's, they charge them a lot of money for it.

I have a question, I know the utility company don't charge residential customer the bad power factors. but how about off grid system? does the bad power factor equipment affect the amount current draw from the battery bank?

Thank you.

[russ]

Here everything is 3 phase power - my home main panel has a 430 volt (or there abouts) 3 phase feed - power factor is of no consideration for residential.

[Mike90250]

I have a question, I know the utility company don't charge residential customer the bad power factors. but how about off grid system? does the bad power factor equipment affect the amount current draw from the battery bank?

Thank you.

The watts drawn from the battery = watts consumed (+ overhead) BUT, the inverter has to be able to support the poor power factor. So if you have a 1Kw load, with a .6PF, your inverter is required to do the work of 1.6Kw and consumes 1Kw from the battery. When the I & E vectors get out of phase from poor power factor, the inverter has to be the device that keeps it all working.

[Colt45]

Here everything is 3 phase power - my home main panel has a 430 volt (or there abouts) 3 phase feed - power factor is of no consideration for residential.

Wow, in a residence... Why? What do you power at that voltage?
Also PF is a problem in all 3 phase systems, non linear loads cause bad thing to happen. Try loading a generator with 100% reactive loads some time if you want a demo.

[Colt45]

Why not just install a three phase inverter or three single phase units?
You say you have only one phase per floor but that would only have a 115V panel? Most of the time you will have a single phase panel feed with two of the three phase legs to give you 115/230v.

Is there a main 3 phase disconnect for the entire service or did each unit get it's own disconnect? You should have all 4 wires in one place at the service entrance location, put the inverters in that spot. (or run from it)