Xantrex GT5.0-NA-240, Руководство пользователя

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Planning the Installation
975-0334-01-01 2–3
PV Array 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 of the inverter. Ensure
that the open circuit voltage (V
oc
) of the PV array is within the MPPT operational
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.
Voltage
requirements The maximum power point voltage (V
MPP
) of a string connected to the GT
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
oc
is below the lower limit of the MPPT
range, the inverter remains off-line and does not deliver power.
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.
Table 2-1 MPPT Operational Window
Voltage Effect of Array Voltage Inverter Mode
V
oc
< Lower limit of MPPT range Inverter not operating. Off-line
V
MPP
< Lower limit of MPPT range
(V
oc
> Lower limit of MPPT range)
Operating voltage shifts to lower limit of
MPPT range; the array is not at its
maximum power point. On-line (low power)
V
MPP
within MPPT range Maximum harvest of solar energy. On-line (MPPT window)
V
MPP
between upper limit of MPPT range
and absolute maximum V
oc
Does not allow maximum harvest of solar
energy. On-line (power derating)
V
MPP
> absolute maximum V
oc
(or V
oc
> absolute maximum V
oc
)
Inverter stops delivering power and shuts
down. Inverter may be damaged. Off-line (shutdown)
CAUTION: Equipment damage
To prevent damage to the inverter, the array voltage must never exceed 600 V
oc
(open
circuit voltage) under any condition.