Empirical Models Applied to Distributed Energy Resources—An Analysis in the Light of Regulatory Aspects

Abstract

According to the International Electrotechnical Commission (IEC) 61853 standard, the power rating of photovoltaic (PV) modules must be done on a measurement matrix that broadly covers the ranges of operating conditions encountered in the field. These results are becoming more frequent in recent module datasheets. This paper investigates the effectiveness of applying existing empirical PV performance models while using a matrix with 18 operational records, similar to the 22 that were recommended by IEC 61853, as an alternative to the thousands of records that are conventionally used to determine their coefficients. A review of fifteen empirical models is presented and the procedures for determining their coefficients are discussed. In order to validate them, they were applied to data from fourteen PV modules, which remained installed outdoors for about one year, in three locations with distinct climate types. Although the uncertainties that were obtained with the proposed approach, as compared to the conventional one, are about 1% higher for xSi and CdTe modules, and somewhat higher for mSi and CIGS modules, the total uncertainties were only around 5%, a value that is quite adequate for evaluating module performance. Moreover, these uncertainties were from two to five times smaller than those that were obtained by the method that was recommended by IEC 61853 for this purpose.

Development of a day-ahead solar power forecasting model chain for a 250 MW PV park in India

“…GTI incident on the module and the cell temperature influence efficiency and, consequently, the DC power output. PV module efficiency can be modeled using detailed diode equivalent circuits [32,33] or as empirical functions of incident irradiance and cell temperature [12,[34][35][36][37]. An increase in operating cell temperature beyond 25 °C has a negative impact on the electrical efficiency of PV modules, and the losses can be significant for regions like India [38][39][40].…”

Validation of an outdoor efficiency model for photovoltaic modules

“…Several PV efficiency models have been developed, i.e., Fifty-three models are presented in [5] and twenty-three are presented in [6]. Also in [7], an extensive study on empirical models is presented, which presents the errors comparison among 15 models. Several models are based on the model presented in [8] that defines the efficiency as a function of the temperature of the cell and the irradiance.…”