3-ph Net Metering

[Open Neutral]

This is a reverse fork from two threads:


http://forums.mikeholt.com/showthre...phase-transformer-with-swapped-leads-to-meter

http://forums.mikeholt.com/showthread.php/138359-240-120-3ph

So we'll have grid-tie inverter{s} selling back via the Open Delta xfmr bank. Given N dollars, we could split it between all three phases, or put more KW of panels and inverters on the "lighter" phase.

I'm trying to visualize what happens when we have say 3KW of three-phase load, and single-phase grid-tie *excess* of 3KW. Is the meter really stationary?

I suspect it's more complex than just the metering. Don't retail grid-tie contracts pay less in {sell-back} than in consume?

 

[Electric-Light]

I seem to recall buyback being higher than retail rate as an incentive to do home power generation thing.

I don't really know how the accounting works though.

Let's just say buyback is 16c/kWh and purchase is 8c/kWh

Do you use two meters or do you only get paid on the portion that exceeds your usage?

Like if you generated 1,000kWh and you used 800kWh

Do you simply get paid 200kWh @ 16c/kWh or do you get paid 1000kWh @ 16c/kWh and pay 8c/kWh @ 800kWh?

 

[tallgirl]

It depends on the tariff or other contractual arrangement.

I buy at 10.5c and sell at 7.4c. With my former provider it was 14.5c both ways.

 

[Open Neutral]

I'm drifting off-point. Ignoring the price difference for now; does a 3ph wattmeter consider 3X single-phase watts and 1X 3ph watts to be equal?

 

[ggunn]

I'm drifting off-point. Ignoring the price difference for now; does a 3ph wattmeter consider 3X single-phase watts and 1X 3ph watts to be equal?

I would think so. Have you any reason to suspect otherwise?

 

[kingpb]

I would imagine the meter is measuring the current in each phase, using the voltage, and doing the math internally to calculate to total 3ph power.