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028, 029
PV reverse con-
nection fault
1. Check whether the corresponding string is of re-
verse polarity. If so, disconnect the DC switch and
adjust the polarity when the solar radiation is low
and the string current drops below 0.5A.
2. Check whether PV strings connected to the
same MPPT have the same number of PV modules.
If not, take corrective measures.
3. If the alarm persists, contact SUNGROW.
039
Low ISO
resistance
Wait for the inverter to recover. If the fault occurs
frequently:
1. Check whether the insulation resistance protec-
tion value is extremely large through the App, and
ensure that it complies with the local regulations.
2. Check the resistance to ground from the PV
module/cable. Take corrective measures in case of
leading to short circuit or damaged insulation layer.
3. If the cable is normal and the alarm occurs on
rainy days, check it again when the weather turns
fine.
4. If the fault occurs on a cloudy day without rain
but there is stagnant water or vegetation on site,
clear the water and vegetation. If the fault persists,
check it again when the weather turns fine.
5. If the alarm persists, contact SUNGROW.
106
Grounding cable
fault
1. Check whether the AC cable is correctly
connected.
2. Check whether the grounding cable and wire
cores are wrongly insulated.
3. If the alarm persists, contact SUNGROW.
User Manual