Checking Solar Array And Inverter Compatibility; Process For Selecting The String Fuse Nominal Current Rating Ifn; Implementing Short-Circuit And Thermal Overload Protection; Protecting The Inverter And Ac Output Cable From Short-Circuits - ABB PVS300 Product Manual

Checking solar array and inverter compatibility

Check that:
• Solar modules and DC cables used in the system are Protection Class II certified
(double insulated).
• Solar modules used in the system do not require grounding of DC+ or DC-
terminals.
• Solar modules used in the system are all of the same type.
• Solar strings to be connected to the inverter all have an equal configuration.
• Solar string and array maximum short circuit currents and open circuit voltages
match the rated values of the inverter under local ambient conditions.
• Solar array operating voltage range lies between the limits of the maximum power
point tracking (MPPT) voltage range.
• The inverter's standard 12A string fuse rating is adequate and compatible with the
solar array design and installation materials. Change the string fuses to a lower or
higher current rating if necessary to provide adequate system protection and
functionality. See section
Process for selecting the string fuse nominal current rating I
• Define the nominal short circuit current I
relevant solar module.
• Define the maximum allowed series fuse rating or reverse current rating I
the data sheet of the relevant solar module.
• Define the conductor current carrying capacity I
under the planned installation conditions. See section
on page 34.
• Correct fuse current rating under planned installation conditions:
I > 1.56 × I
FN SC
I ≤ I or if I
FN R R
I ≤ I
FN C

Implementing short-circuit and thermal overload protection

Protecting the inverter and AC output cable from short-circuits

The inverter has an integrated automatic AC overcurrent trip function which limits
inverter damage if there is, for example, an AC side short-circuit or other overcurrent
event. Install an external circuit breaker at the distribution board to protect the AC
cable according to local regulations, appropriate AC line voltage and the rated current
of the inverter.
Warning messages
not specified in module data sheet I
Planning the installation 37
on page 95.
rating from the data sheet of the
SC
of the used string cable type
C
Selecting the power cables
< 2 × I
N
FN
from
R
SC