Appendix – HT instruments SOLAR I-V User Manual
Page 72
I-V400 - SOLAR I-V
EN - 70
11. APPENDIX
11.1. TESTING PHOTOVOLTAIC SYSTEMS
According to the requirements of the laws in force, the result of the test depends on
settings about Temperature effects compensation and PRp calculations:
Corr.Typ
e
Tcel value
PRp calculation
Guidelin
e
Tmod
Tcel = PV Module Temp. measured
n
STC
p
ca
P
G
G
Rfv
P
PRp
2
CEI
82-25
(Italian
Guideline)
Tamb
or
Tenv
Tcel = PV module Temp. calculated
800
G
20
Tamb
Tcel
p
NOCT
nDC
Tcel = PV Module Temp. measured
n
ca
cel
p
STC
P
P
T
G
G
PRp
25
100
1
- - -
where:
Symbol Description
Meas.
unit
p
G
Irradiance on PV module surface
2
W/m
STC
G
Standard Irradiance = 1000
2
W/m
n
P
Nominal Power = sum of all power module (Pmax )
included in the part of PV plant under test
kW
ca
P
AC Active Power measured
kW
C)
40
Tcel
(if
100
40)
-
(Tcel
-
1
C)
40
Tcel
(if
1
2
Rfv
Thermal Corrective factor
Absolute value of Pmax thermal coefficient
C
%/
NOCT
Normal Operating Cell Temperature (@ 800W/m
2
, 20°C,
AM=1.5, vel. Aria =1m/s).
C
%/
Previous relationship are valid if Irradiance > Min Irraddiance value and the Irradiance
values are “steady”: if IP
1min (Irr max – Irr min) < 20W/m
2
The final OUTCOME can be:
Non-displayable: if the obtained values are inconsistent (e.g. PRp >1.15) or if
irradiation has never reached a steady value > minimum threshold set.
The maximum performance point (PRp) of the system
The highest performance (maximum value of PRp) is detected according with previous
relationships.