78
000871AG-F
5 - Installation
In these versions, you must directly connect the individual strings coming
into the inverter (do not make field switchboards for parallel strings). This
is because the positive side (+)
35
and negative side (-)
34
string fuses,
situated on each input, are not rated to take strings in parallel (array).
This operation can cause damage to the fuse and consequently malfun-
ctioning of the inverter.
The sizing of the string fuses must be made taking into account the 2
following conditions:
1.
The nominal current of the fuse (I
rated
) must not exceed the maximum
rating of the fuse to be used in series on the strings (maximum series
fuse rating), indicated in the technical data of the PV modules in com-
pliance with standard EC 61730-2:
I
rated
< Maximum series fuse rating
2.
The fuse rating (I
rated
) must be determined based on the string current
and on the sizing guidelines provided by the manufacturer to avoid unti-
mely tripping. As a general guideline, based on the photovoltaic modules’
short circuit current (I
sc
), it is possible to calculate the rating of the fuse
with the following formula:
I
rated
> (1.4 ≈ 1.5)*I
sc
Fuses must be chosen among the standard commercially available ra-
tings, 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 mo-
dule
- Thermal derating of the fuse
- Maximum return current of the PV modules installed
FIMER can supply fuse kit:
Code
Description
Quantity
KIT 10 FUSES 15A
Kit of 15A fuses
10
For effective calculation taking real installation conditions into account, refer to the docu-
ments supplied by the protection fuse manufacturer.
Содержание PVS-50-TL
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