Pv Array Voltage And Mppt Requirements - Xantrex GT5.0-NA-240 Owner's Manual

PV Array Voltage and MPPT Requirements

MPPT operational
window
Table 2-1 MPPT Operational Window
Voltage
V < Lower limit of MPPT range
oc
V < Lower limit of MPPT range
MPP
(V > Lower limit of MPPT range)
oc
V within MPPT range
MPP
V between upper limit of MPPT range
MPP
and absolute maximum V
V > absolute maximum V
MPP
(or V > absolute maximum V
oc
Voltage
requirements
975-0334-01-01
WARNING: Shock hazard
Whenever a PV array is exposed to sunlight, a shock hazard exists at the output wires or
exposed terminals. To reduce the risk of shock during installation, cover the array with an
opaque (dark) material before making any connections, and always test for voltage before
touching exposed wiring or devices.
The MPPT software maximizes the output energy of solar arrays as long as the
operating voltage is within the MPPT operational window of the inverter. Ensure
that the open circuit voltage (V
window. See "Input voltage, Maximum Power Point Range" in Appendix A,
"Specifications" for the MPPT operational window of each GT Inverter model.
Effects of array voltages outside of the MPPT operational window are shown in
Table 2-1.
Effect of Array Voltage
Inverter not operating.
Operating voltage shifts to lower limit of
MPPT range; the array is not at its
maximum power point.
Maximum harvest of solar energy.
Does not allow maximum harvest of solar
energy.
oc
Inverter stops delivering power and shuts
oc
down. Inverter may be damaged.
)
oc
The maximum power point voltage (V
Inverter should preferably be above the lower limit of the MPPT range for that
model. If it is below the lower limit of the MPPT range, the inverter continues to
operate, but it regulates the PV voltage to the lower limit of the MPPT range.
Because the array is not operating at its maximum power point, this may result in
lower than expected energy harvest. If V
range, the inverter remains off-line and does not deliver power.
CAUTION: Equipment damage
To prevent damage to the inverter, the array voltage must never exceed 600 V
circuit voltage) under any condition.
) of the PV array is within the MPPT operational
oc
) of a string connected to the GT
MPP
is below the lower limit of the MPPT
oc
Planning the Installation
Inverter Mode
Off-line
On-line (low power)
On-line (MPPT window)
On-line (power derating)
Off-line (shutdown)
(open
oc
2–3