Typical Errors On I-V Curves And Troubleshooting - HT I-V600 User Manual

11.2.

TYPICAL ERRORS ON I-V CURVES AND TROUBLESHOOTING

Measurement
Good measurement
Low short circuit current
High short circuit current
Low open circuit voltage
Low current ratio Impp/Isc
Event
• The measured curve extrapolated
to STC (blue) and the curve as
declared by the
(black) of the modules match.
• Irradiance
sensor
differently than the string under test
• Reflections on the irradiance sensor
• Wrong
module
configuration of PV system
• Environmental
contaminants
modules (soiling, dirt, snow, debris)
• Far distance obstruction (shading)
• Aging
• Irradiance
sensor
differently than the string under test
• Reflections on the irradiance sensor
• Dirt on the irradiance sensor
• Wrong
module
configuration of PV system
• Irradiance sensor defect
• Low temperature measurement
• Wrong
numbers
selection at configuration of PV
system
• Shorted bypass diodes
• Soiling across modules
• Tapered shades
• Small current mismatch
• Degradation of cell shunt resistance
EN - 76
Troubleshooting
• No error, save data and
move to next string to test
manufacturer
• Orient the irradiance sensor
oriented
properly
• Set the instrument properly
• Clean the modules
selection at
• Remove the obstructions
• Check the modules for
on
blindness, humidity, etc.
• Replace affected modules
• Orient the irradiance sensor
oriented
properly
• Clean the irradiance sensor
• Remove the obstructions
• Check the irradiance sensor
selection at
for blindness, humidity, etc.
• Set the instrument properly
• Replace affected sensor
• Attach
properly
of module
temperature location
• Select the AUTO mode
• Set the instrument properly
• Replace affected modules
• Clean the modules
• Un-shade the modules
• Check that currents match
• Replace affected modules
I-V600
the thermocouple
to a typical