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11.3.1 Interpreting the measurement results
The parameters measured by the instrument are described below
Parameter
Description
P
max
Maximum Power of the PV module/string measured by the instrument
V
mpp
Voltage at maximum power point
I
mpp
Current at maximum power point
V
oc
Open-Circuit Voltage
I
sc
Short-Circuit Voltage
FF
Fill Factor %
DP
max
Difference between the maximum power measured by the instrument, referred to
STC, and the maximum power declared by the manufacturer, Pnom (@ STC)
DPmaxAvg
Available only for measurements on strings: indicates the DPmax on only one
module. This value ought not to be considered reliable for the test’s purposes.
Result of the measurements
Result
Conditions
Note
OK
Tol
(-)
* P
nom
(P
max
- P
nom
)
Tol
(+)
* P
nom
DEGRADATION NOT
TAKEN INTO ACCOUNT
Tol
(-)
* P
nom1
(P
max
- P
nom
1
)
Tol
(+)
* P
nom1
DEGRADATION TAKEN
INTO ACCOUNT
NO
(requirements not satisfied)
Tol
(-)
* P
nom
(P
max
- P
nom
)
Tol
(+)
* P
nom
DEGRADATION NOT
TAKEN INTO ACCOUNT
Tol
(-)
* P
nom1
(P
max
- P
nom
1
)
Tol
(+)
* P
nom1
DEGRADATION TAKEN
INTO ACCOUNT
Where:
(P
max
- P
nom
)
DP
max
(degradation not taken into account)
(P
max
- P
nom1
)
DP
max
(degradation applied)
Tol
(-)
(%) * P
nom
= Negative tolerance declared by the manufacturer (degradation not taken into account)
Tol
(-)
(%) * P
nom1
= Negative tolerance declared by the manufacturer (degradation taken into account)
Tol
(+)
(%) * P
nom
= Positive tolerance declared by the manufacturer (degradation not taken into account)
Tol
(+)
(%) * P
nom1
= Positive tolerance declared by the manufacturer (degradation taken into account)
DPmax:
