An experimental study for efficiency modeling of grid-connected photovoltaic system

ABSTRACT

As a key factor, it is vital to mathematically model the electrical efficiency of photovoltaic (PV) systems. This paper investigates the efficient modeling of a 2.5 kW grid-connected PV system, located in Mahan, Kerman, Iran, with respect to different factors like solar radiation, humidity, dust deposition, temperature, and shading. For this aim, different nonlinear models are considered and a curve-fitting approach is used to optimally determine the unknown parameters. Over the case study, simulation results show that when the dust deposition is not included in the modeling (solar radiation, ambient temperature, cell temperature, humidity, and shading as inputs), the third-degree polynomial model leads to more accurate result than the other models. By use of the third-degree polynomial model, the value of root mean square error (RMSE) for train and test data sets is obtained 0.0123 and 0.0109, respectively. In this case, the average RMSE value is 0.0116. On the other hand, when dust impact is included in the modeling (solar radiation, ambient temperature, humidity, and number of dusty days as inputs), the accuracy of the exponential model is more than the other ones. In this case, the value of RMSE for both train and test data sets is obtained 0.0018. Sensitivity analysis shows that the system efficiency depends mainly on the radiation, cell temperature, and dust and less on the humidity.

KEYWORDS:

• Photovoltaic efficiency
• mathematical modeling
• environmental factors
• shading
• dust deposition

Acknowledgements

Authors would like to thank North-Kerman Electricity Distribution Company (NKED) for financial support.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

Date is available on request from the authors.

Additional information

Funding

This work was supported by the North-Kerman Electricity Distribution Company (NKED).

Notes on contributors

Amin Mohammad Rafiei

Amin Mohammad Rafiei is currently working toward the M.S. degree of Electrical Engineering in Graduate University of Advanced Technology, Kerman, Iran. His research interests are photovoltaic modeling and optimization methods.

Alireza Askarzadeh

Alireza Askarzadeh is currently Professor of Electrical Engineering with the Department of Energy in Graduate University of Advanced Technology, Kerman, Iran. His research interests include power system optimization, power system planning and renewable energy systems.