HT instruments MPP300 - Manual (Page 26)

MPP300
EN - 24
9. APPENDIX – THEORETICAL OUTLINE
9.1. 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 (see MASTER
instrument settings):
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 (see user manual
of the MASTER instrument) 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 (see user’s
manual of MASTER instrument).
 The maximum performance point (PRp) of the system
The highest performance (maximum value of PRp) is detected according with previous
relationships.