Z200 PV Analyzer
User Manual
6
Applications and measurements
Some rudimentary control and assessment of the light reaching the string and individual PV
modules is necessary. I.e. in order to accurately detect and localize ground faults, and discon-
nects in cables and connectors, all the modules in the string under test need to be illuminated
by at least 100
W
m
2
. The most accurate results are obtained when the irradiation level is steady
throughout your measurement. This is also the case if you want to estimate the overall string
series resistance R
S
. When checking the health state of module bypass diodes it is also neces-
sary with ambient sunlight intensity at each module of at least 100
W
m
2
. Please note that testing
the health state of the diodes in a specific PV module in the string, requires blocking the sunlight
from reaching that module. If R
P
of the string or a subset of the string down to individual cells
or modules needs to be measured the sunlight needs again to be blocked from reaching the PV
cells or modules being tested, however this can be achieved by measuring at nighttime (I.e. R
P
of the entire string).
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