Investigation of Accuracy of various STC Correction Procedures for I-V Characteristics of PV Modules Measured at Different Temperature and Irradiances
Yogeswara Rao Golive1, Hemant K. Singh1, Anil Kottantharayil1, Narendra Shiradkar1, Juzer Vasi1, Paul Ndione2, Dean Levi2
1National Centre for Photovoltaic Research and Education, Indian Institute of Technology Bombay, Mumbai, India
/2National Renewable Energy Laboratory, Golden, CO, United States

This paper presents a simulation study to estimate the accuracy of various STC correction procedures as a function of irradiance and temperature in field. The normalized errors in maximum power (Pmax) in STC correction for the IEC 60891 procedure 1, Modified IEC 60891 procedure 1 and Standard Irradiance and Desired Temperature (SIDT) procedures were compared at various irradiances and temperatures. Also, the most accurate method to predict I-V characteristics of modules based on single diode model was identified by comparing eight different methods.  The IEC 60891 procedure 1 was found to have least normalized error, however it is not always suitable in field as it requires I-V data at various temperatures and irradiances. .  Out of the remaining two procedures Modified IEC 60891 1 procedure is having lowest normalized error compared to SIDT in the range of temperature (50 0C to 75 0C) and irradiance (700 W/m2 to 1000 W/m2) which are typically encountered in outdoor measurements. The experimental validation of simulation results is being performed using the TempCoSpot system at NREL

Area: Sub-Area 5.7: Performance Testing and Standards