Inverters: Grid-tie
Grid-tie, or utility inter-tie, inverters convert DC power from PV modules into AC power to feed into the utility grid. There are two major types of grid-tie inverters: string inverters and low voltage inverters.
String inverters are wired together in series to achieve a higher voltage. These inverters are designed to run at voltages up to 600 VDC. String wiring is faster to install, more efficient and allows the use of smaller gauge wire. DC voltage this high can be very dangerous and life threatening, so string inverters should be installed and serviced by qualified electricians.
A grid-tie PV system uses the utility company, in effect, as its storage battery. When the sun is shining, your electricity comes from the PV array, via the inverter. If the PV array is generating more power than you are using, the excess is sold to the power utility company through your electric meter, by making the meter run backwards. When you need more power than the PV array can supply, the utility makes up the difference. This type of system makes the most sense in most cases where you have utility power, because there are no batteries to maintain or replace. Unfortunately, if the utility power goes down, this type of inverter will go off too, regardless of whether or not the sun is shining.
Fronius IG Inverters
The FRONIUS IG 2000,IG 3000 and IG 2500-LV (low voltage 208V) photovoltaic inverters utilize high frequency architecture to deliver higher reliability and performance while reducing size, weight (26 pounds) and installation cost. The new Fronius IG 4000, IG 4500-LV (low voltage 208V) and IG 5100 grid tied inverters that output up to 5,100 Watts but still weigh only 42 pounds.
FRONIUS IG products can withstand the test of time in harsh environments and heavy use. The FRONIUS IG combines several key design elements to insure operation at a high efficiency under all operating conditions. Fronius employs Active Cooling technology in its FRONIUS IG inverters. They inverters operate reliably at full power, without de-rating, over a wider range of temperatures than competing inverters.
Phase Shift Technology- Unique phase-shift design maximizes switching efficiency. Switching losses are minimized through an innovative process, allowing an even higher efficiency to be maintained.
A wide input voltage range permits the use of modules of every power size and voltage. You can easily fine-tune your system with different wattage modules and string configurations. The voltage window for the entire FRONIUS IG series is 150-500Vdc.
Every FRONIUS IG comes standard with integrated DC and AC disconnects. Both DC and AC electrical connections are made in the convenient installer accessible wiring compartment. Pre-wired DC breaker to a heavy-duty terminal block that accepts up to eight #8 AWG conductors (four input strings). The DC/AC disconnects are UL rated and meet the technical requirements of the National Electric Code for PV systems.
SMA Grid-Tie Inverters
The SMA Sunny Boy is the most successful in connecting PV-plants. For over 20 years, SMA has been developing and manufacturing systems for energy conversion in railway applications and industries. With their experience, SMA is an essential component of your PV plant. SMA components are designed for 20 years of performance. Each unit comes with a 10 year warranty that can be extended to 15 years.
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