Fronius String Control 100/12 - Handbuch (Seite 73)

71
EN-US
Criteria for the Proper Selection of String Fuses
General You can give Solar modules extra protection by using string fuses in the String Control 100/
12.
Crucial for the fuse protection of the solar modules is the maximum short circuit current I
sc
of the relevant solar module.
Criteria for the
Proper Selection
of String Fuses The following criteria must be met for each solar module string when using fuse protection:
-
I
N
> 1.8 x I
SC
- I
N
< 2.4 x I
SC
- U
N
>/= max. Input voltage of the inverter used:
Fronius CL 36.0 / 48.0 / 60.0 etc. 600 V DC
Fronius IG Plus / IG Plus V etc. 600 V
- Fuse dimensions: Diameter 10 x 38 mm
I
N
Nominal current rating of the fuse
I
SC
Short circuit current for standard test conditions (STC) according to solar module
data sheet
V
N
Nominal voltage rating of the fuse
Effects of Using
Underrated Fuses With underrated fuses, the nominal current value may be less than the short circuit current
of the solar module.
Effect:
The fuse may trip in intensive lighting conditions.
Fuse recommen-
dations
You should only use the following fuses, which have been tested by Fronius, to ensure
problem-free fuse protection:
-
Littelfuse KLKD fuses
Fronius shall not be liable for any damage or other incidents resulting from the use of other
fuses. Moreover, all warranty claims will be voided.
Application Ex-
ample e.g.: Maximum short circuit current (I
SC
) of the solar module = 5.75 A
According to the criteria for selecting the right string fuses, the fuse must have a nominal
current greater than 1.8 times and less than 2.4-times the short circuit current:
-
5.75 A x 1.8 = 10.35 A
- 5.75 A x 2.4 = 13.8 A
Fuse to be selected from the 'Fuses' table:
KLK D 12 with a nominal current of 12.0 A and a nominal voltage of 600 V AC / DC
NOTE! The nominal current value of the fuse must not exceed the maximum fuse
protection value specified in the solar module manufacturer's datasheet. If a max-
imum fuse protection value is not specified, please request it from the solar mod-
ule manufacturer.
NOTE! Only select fuses whose nominal voltage is higher than or equal to the
max. input voltage of the inverter being used.