Input to the grid from Inverter

System

Hello....I just purchased a new Whisper 200 and it will be set for 48 volt operation. I have a SW4048 Trace inverter that I have had since 1995 and as you know....The inverter converts the 48 volts to 120 volts AC and my question is: Is 120 volts AC ok for Grid tie systems or does it have to be 220? Is there a simple schematic available that shows the hookup from the Wind Generator to the Grid?....

BB.

Re: Input to the grid from Inverter

You can take a look here (Xantrex Site):

http://www.xantrex.com/web/id/18/learn.asp

What makes the magic for anything (wind/solar/battery) to grid connection is

1) Must be legal for your location
2) Usually (in the US) you would need a signed off building permit
3) You need the OK from the Utility Company to connect your specific Grid Tie system at your address to the mains
4) Usually, you will need a licensed electrician to do/sign off on the work
5) You need a specific inverter (or Grid Tie Interface module) that syncs with the Utility Mains, and can accept the power (wind/solar/battery) power for conversion to the grid.

For your application, if you are happy with the SW4048, there may still be available that "Xantrex - SW Series GTI Grid Tie Interface"... I don't know anything about it and it appears to have dissappeared from Xantrex's site--so I don't know if it is still available/recommended for use.

Using the Xantrex Grid Tie Interface (GTI), the SW II inverter converts energy from multiple renewable energy sources, such as solar, wind, and microhydro, into AC power, selling power you don't use back to the utility. Software/hardware revision 4.2 or higher is required to connect the SW4024, SW4048, or SW5548 to the GTI.

Regarding the 120 vs 240 VAC for grid tie connection... Either will work, but it might get a bit more dicey in terms of actual connections and NEC requirements...

Somebody else here can give you the specifics from NEC, but basically, if you have, say a 120 amp main line into your home, then you are allowed up to ~20% (?) of the panel's capacity (in amps) to be generated power for sale back to the grid.

So, for example, the 120 amp panel would max out at 24 amps at either 120 or 240 vac... At 120vac, 80% (NEC) of 24 amps or 19.2 amps would only be about 2,300 Watts. Whereas at 240 volts, the power allowed would be over 4,600 Watts.

I am not the expert here on code compliance--but having to resize your panels (if under the allowed rating) would be an issue--as well as the fact that the wire would have to be able to handle twice the current at 120 VAC (for the same amount of power).

In the case of the Whisper 200--its maximum power output is ~1,000 watts--so unless you have other energy supply sources (solar panels), you would not need to dump all 4,000 watts onto the grid at one time (assuming the SW40xx and GTI are programmable for amount of power exported to grid).

-Bill

System2

Re: Input to the grid from Inverter

Lonnie,

If you would--will you describe to us the components of your R.E. system?

crewzer

Re: Input to the grid from Inverter

Check the owner's manual... there are some "old" versions of the SW inverter that include a utility interactive (grid-tie) mode.

See page 83 here: http://www.xantrex.com/web/id/938/docserve.asp

HTH,
Jim / crewzer

System2

Re: Input to the grid from Inverter

Hey Lonnie

NOt to rain on your parade but wind only might not be the best grid tie-in.

I have an off-grid hybrid system using an H 80 (earlier version of what you have) PV, Genset and 4048 inverter. My power results for the last 2 years, in a pretty good wind harvesting location are between 660-700 Kw hours for each year. For me, that's 25% or so of household consumption at 7.5Kwh per day. If you're grid tied (or still on it) and your daily's are 20kw or more per day, that's worth about 3 weeks of grid power. There's lots of nebulous advertising regarding using wind to "lower your electric bill", some of it questionable. The fine print sometimes gives average wind speeds you'd find only on the glaciers of Antartica!

My suggestion is if you're going to go to the expense and commitment of putting up a wind turbine only, just use it to charge your batteries (got batteries?) and have a grand UPS for power outs, or some other arrangement. Our experience here has shown we'd have little to back feed the grid with and only in the summer (PV) and a few weeks in the spring and fall (wind).

If i misunderstood your arrangement, please to forgive. Hope whatever you build works out.

Cheers

System2

Re: Input to the grid from Inverter

Lonnie,

I would presume that you already have--or plan on installing a 48V battery configuration to go with that 4048 and 48 volt turbine. I don't see how it would work otherwise. That inverter requires a battery, as opposed to the AC/DC/AC inverters like the Windy Boy or Grid Tek, which do not. Those inverters, by the way, require high voltage turbines.

In the case of the Whisper 200, the battery is necessary to hold the turbine voltage down. If you refer to your inverter set-up parameters, you will see that the inverter accepts voltage in some pretty narrow confines--which that turbine would exceed pretty quickly.

Another thing to consider is the daily charging of the battery system...bulk, absorb, float--so, hopefully you have--or envision another charging source, or you'd run the risk of degrading the batteries over time.

Those of us that run SW series inverters already know that you can "sell" energy based upon specific times during the day--or, after system voltage reaches a pre-determined point. 120V is fine.