Comparison of the Methods of Calculation of Measurements Standardization on the Outdoor Photovoltaic Modules

Abstract

To compare the performance of PV modules, it was required to translate the measured I-V characteristics, to use certain standard conditions. The International Electrotechnical Committee (IEC) has defined the standard test condition (STC) for PV modules with 1000 W/m 2 irradiance with AM 1.5 and 25°C module temperature. The IEC has also published some standard correction procedures (contained in IEC 60891) to translate irradiance and temperature values between different. IEC 60891 defines a procedure which helps to translate the measured I-V characteristics photovoltaic devices at standard test condition (STC). The IEC 60891 translation procedures can be applied only for the 20% variation in the irradiance, the irradiance should not be below 800 W/m 2 for translation at STC but also for limit temperatures (35 ° VS). In our study we will use crystal technology and the temperature measurements carried out at the study site show temperatures varying from 55°C to 65°C. Data from tests in the wild has been converted to standard test conditions (STC) using four methods proposed by AJ Anderson and G. Blaesser, the combination method and the equations from international standard IEC 60891. These methods are compared using data from one year and the correlation between the measured data and the standardized data. The results demonstrated that the combination method has good precision in the STC conversion of the performance of the PV module under different climatic and technological conditions. Then, based on the investigation results of the conversion equations, these translation methods are distinguished by the type of solar cell technology and the field of application. There is a difference between in situ and natural tests, attributed to various factors but mainly to the mismatch between the spectral responses of the PV module and the reference solar cell. The combination method uses irradiance data and temperature and performance parameters under STC conditions of PV modules to predict the maximum output power. Therefore, it is essential to provide reliable weather data before designing photovoltaic power systems.

Comparative of IEC 60891 and Other Procedures for Temperature and Irradiance Corrections to Measured I–V Characteristics of Photovoltaic Devices

“…The approach presented by Dia et al [40] is also named the "combination method", because it uses (Equation ( 21)) to correct I SC and the simple expression (Equation ( 17)) to correct V OC .…”