ABB PRO-33.0-TL Series, Product Manual

Page: 35 / 136

Installation requirements 35
Photovoltaic array and inverter compatibility
Make sure that:
• The PV modules and DC cables are Protection Class II certified (double
insulated).
• The PV modules are not grounded to the DC+ or DC- terminals.
• The PV modules are of the same type and that they have a IEC 61730 Class A
rating.
• The PV strings have an equal configuration for optimized energy output.
• The PV string and array maximum short-circuit currents and open-circuit voltages
for DC inputs match the rated values of the inverter under local ambient
conditions. Refer to
Technical data on page 123 .
• The PV array operating voltage range is in the MPPT voltage range at all ambient
temperatures. Refer to Technical data on page 123 . The string voltage tends to
increase in low ambient temperatures.
• The -SX model is equipped with 15 A string fuses (refer to Technical data on page
123 for fuse types). Make sure that the 15 A string fuses are sufficient and
compatible with the PV array design and installation materials. The nominal
current of the string fuses is defined at 25 °C. Take into account the possible
temperature deviations when you select fuses.

String fuse nominal current rating I
FN
• Read the nominal short-circuit current I
SC
rating from the data sheet of the PV
module.
• Read the maximum allowed series fuse rating or reverse current rating I
R
from the
data sheet of the PV module.
• Define the conductor current carrying capacity I
C
of the used string cable type in
the planned installation conditions.
• The correct nominal current rating I
FN
of the string fuse in the planned installation
conditions:
I
FN
> 1.56 × I
SC
I
FN
≤ I
R
or if I
R
is not specified in module data sheet I
FN
< 2 × I
SC
I
FN
≤ I
C
When you use this formula to select the fuses, take into account the factors that
can cause adjustments to the formula:
•
The thermal derating of the fuse.
• The effective radiation at the installation site.
• The PV module I
sc
temperature dependence at the site.
• The maximum return current of the PV modules.