ABB PRO-33.0-TL Series - Photovoltaic array and inverter compatibility

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 Techn ical da ta 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 Tech nical d ata 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.