ABB PVI-3.0-TL-OUTD-S-US Product Manual page 56

Display Message Causes
E025 Before connecting to the grid, the
Riso Low inverter measures the insulation
Low insulation resistance of the PV array com-
resistance pared to ground. If the insulation
resistance measured by the in-
verter is less than 1 MOhm, the
inverter does not connect to the
grid and shows the "Riso Low" er-
ror. The causes may be:
- Damaged PV panel(s).
- Junction box(es) not properly
sealed, allowing water and /or
damp seepage ;
- Loose connections between
panels allowing humidity leak-
age;
- Poor quality cable junctions;
- Presence of unsuitable (trigger
voltage lower than the character-
istics of the PV array strings) or
damaged overvoltage surge ar-
resters outside the inverter in the
DC section.
- Presence of damp inside the
field panel, if there is one.
E026 Wrong measurement of the ref-
Vref Error erence voltage inside the equip-
Bad internal ment.
reference voltage
E027 Error in the internal measurement
Error Meas V of the grid voltage (imposed by
VGrid Measures regulations) to have a measure-
Fault ment redundancy (2 measure-
ments on the same parameter
carried out by two different cir-
cuits).
E028 Error in the internal measurement
Error Meas F of the grid frequency (imposed by
FGrid Measures regulations) to have a measure-
Fault ment redundancy (2 measure-
ments on the same parameter
carried out by two different cir-
cuits).
Solution
If possible, measure the insulation resistance us-
ing a megohmmeter positioned between the pho-
tovoltaic field (positive terminal short-circuited to
the negative pole) and ground (as described in the
relevant section: "checking the ground insulation of
the PV array"). If the measured value is less than 1
mega ohm, the photovoltaic array must be checked
by a technician/installer to identify and eliminate
the problem If the measured value is greater than
1 mega ohm and the error warning continues to be
present, contact customer service.
(Damp increases leakage and can therefore be the
cause of a reduction in insulation resistance).
Internal error that cannot be checked externally.
If the problem persists (even after switching the
inverter off and then on again), contact customer
service.
This is an error inside the inverter that cannot be
checked externally. If the problem is persistent
(even after switching the inverter off and then on
again), contact customer service.
This is an error inside the inverter that cannot be
checked externally. If the problem is persistent
(even after switching the inverter off and then on
again), contact customer service.
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5 - Troubleshooting