Xantrex Technology GT 2.5-DE - Manual (Page 26)

Installation
2–6 975-0253-01-01
Voltage and MPPT Requirements
MPPT operational
window The MPPT software maximizes the output energy of solar arrays as long as the
operating voltage is within the MPPT operational window. Ensure that the PV
array used in the system operates within the MPPT operational window.
Effects of array voltages outside of the MPPT operational window are shown in
Table 2-1.
Voltage
requirements The maximum power point voltage of a string connected to the GT Inverter should
be a minimum of 195 Vdc. If it is less than 195 Vdc, the inverter will continue to
operate, but it will regulate the PV voltage to 195 V. Because the array will not be
operating at its maximum power point, this may result in lower than expected
energy harvest.
Maximum PV
Power The solar array should be sized such that its maximum power output does not
exceed the limits of the MPPT operational window (195 to 550 Vdc). See
“Guidelines for Matching PV Array Size to Xantrex Grid Tie Solar Inverter
Input”.
The array voltage should never exceed 600 V
OC
(open circuit voltage) under any
thermal condition.
Likewise, ensure that the Isc (short circuit current) rating of the array at any
temperature does not exceed the short circuit current rating of the inverter.
Table 2-1 MPPT Operational Window
Voltage Effect of Array Voltage Inverter Mode
< 195 Vdc Operating voltage will be shifted to 195 Vdc;
the array will not be at its maximum power
point Low power
195 to 550 Vdc Maximum harvest of solar energy MPPT window
550 to 600 Vdc Will not allow maximum harvest of solar
energy Power derating
> 600 Will shut down and may cause damage to the
inverter; stops selling surplus energy Shutdown