Installation and Operation Manual Page 95 of 104
(PVI-3.8/4.6-I-OUTD-US Rev.: 1.1)
8 TECHNICAL CHARACTERISTICS
8.1 Input Values
WARNING: The photovoltaic field and system wiring must be configured in
such a way that the PV input voltage is less than the maximum upper limit
independent of the type, the number, and the operating conditions of the
chosen photovoltaic panels.
As panel voltage also depends on working temperature, the number of panels
per string shall be chosen according to the minimum ambient temperature
expected in that special area (see table A).
WARNING: The inverter is provided with a linear output power derating
depending on the input voltage, starting from 470 Vdc (100% output power)
to 520 Vdc (10% output power)
WARNING: The open circuit voltage of the photovoltaic panels is affected
by the ambient temperature (the open circuit voltage increases as the
temperature decreases). Make sure that the minimum temperature estimated
for the installation does not cause the panels to exceed the maximum upper
voltage limit of 520 Vdc. As an example, the following table shows for
typical panels of 36, 48, and 72 cells the maximum voltage of each panel as a
function of the temperature (assuming a rated open circuit voltage of 0.6 Vdc
per cell at 77°F and a temperature coefficient of -0.0041V/°F). The table
shows, therefore, the maximum number of panels that can be connected in
series as a function of the minimum temperature at which the system will
operate. Consult the panel manufacturer for the correct temperature
coefficient of V
oc
, before calculating the maximum voltage of the
photovoltaic array.
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