EN
66
2. The fuse rating (Irated) must be determined based on the
string current and on the sizing guidelines provided by the
manufacturer to avoid untimely tripping. As a general guideline,
based on the photovoltaic modules’ short circuit current (Isc), it
is possible to calculate the rating of the fuse with the following
formula:
Irated > (1.4 ≈ 1.5)*Isc
Fuses must be chosen among the standard commercially available
ratings, selecting the value that is closest to the obtained result.
The fuse selected with the calculation described previously takes
into consideration derating factors and corrections such as:
• Increase in the effective irradiation of the installation area
• Increase in the Isc on the basis of the high temperature of the
PV module
• Thermal derating of the fuse
• Maximum return current of the PV modules installed
Fimer can supply fuse kits of different values; these kits could be
ordered separately.
NOTE –
D
Refer to
“Kit of recommended spare parts”
paragraph for further information about fuses kit.
NOTE –
D
For effective calculation taking real installation
conditions into account, refer to the documents supplied by
the protection fuse manufacturer.
5.10.2.2 Operations preliminary to the connection of
the PV generator
WARNING –
B
In order to safely perform the preliminary
operations before the connection to the PV generator, the
connection of the ground protection cable
(10)
/
(25)
to the
wiring box is mandatory.
ATTENTION –
A
The installation must be performed by
qualified installers and/or licensed electricians in accordance
with the existing regulations in the country of installation and
in accordance of all safety rules for performing electrical
works. These activity is allowed ONLY with the appropriate
PPE for carrying out this check (overall resistant to electric
arc, dielectric helmet with visor, insulating gloves class 0,
Protective overglove in leather EN420 – EN388, Safety
shoes).
ATTENTION –
A
The reverse polarity can cause severe
damage.
Checking of leakage to ground of the photovoltaic generator:
Measure the voltage present between positive and negative pole
of each string with respect to ground.
If a voltage is measured between an input pole and ground, it
may be that there is a low isolation resistance of the photovoltaic
generator and the installer will have to carry out a check to solve
the problem.
Do not connect the strings if a leakage to ground has been
detected, as the inverter might not connect to the grid.
Refer to
“Verification of ground leakage”
paragraph on
this manual to know how to verify the leakage to ground of the
photovoltaic generator.
Checking of strings voltage:
Measure the voltage present between positive and negative pole
of each string.
If the open circuit voltage of the string is near the maximum value
accepted by the inverter, consider that low ambient temperatures
cause an increase in the string voltage (different according to the
photovoltaic module used). In this case it is necessary to carry
out a check of the sizing of the system and/or a check on the
connections of the modules of the system (e.g.: number of modules
in series higher than the design number).
ATTENTION –
A
Verify that the string voltage is the same in
all the strings that are connecting to the same input channel.
Voltage differences (of the strings connected in parallel)
could reduce performance and unwanted opening of the
fuses.
ATTENTION –
A
Input voltages higher than the maximum
value accepted by the inverter (see technical data table) may
occur the damage of the inverter.
5.10.2.3 Checking the correct polarity of the strings:
• Open the wiring box front cover
(07)
.
NOTE –
D
Only for -S2, -SX2, SY2 versions: Set the wiring
box AC disconnect switch
(09)
to OFF position; otherwise it
will not be possible to open the wiring box cover
(07)
.
• Remove the internal DC Protective shield
(60)
by removing the
two M5 screws.
PVS-100_120-TL_B2_S(X-Y)2
60
