Document Type : Research Paper


Department of Electromechanical Engineering, University of Technology, Baghdad, Iraq.


The probable appearance of localized overheating (hot spot) represents one of the main matters for the reliability and safety of c-Si cells. It entails both a risk for the photovoltaic module's lifetime and a decrease in its operational efficiency. Partial shading is the most common cause of a hot spot in a PV system. The main aim of this work is to analyze the hotspot phenomena by I-V curve as well as IR thermography and investigate the impact of partial shading on the hottest cell experimentally to find its effect on the output power. The results show that at normal operating conditions (G=865W/m2 and Ta=39.7°C) the output power is 89.05W; the temperature difference between the hottest and cooled cell was about 6°C. Moreover, the short circuit current and consequently, the maximum output power reduced if only one cell fully or partially shaded. However, when the hottest cell is shaded by 25%, 50%, 75%, and 100% of the shaded area, the power losses were 37.17 %, 50.05%, 48.61%, and 52.86% respectively. Wheals, the hottest cell temperature was 80.6, 99.1, 101.4, and 62.4°C for 25, 50, 75, and 100% of the shading area, the major temperature difference observed at 75% of the shading area.


  • Output power losses of PV module during irradiance transitions were studied.
  • The maximum output power loss of PV module under hot spot was around 52.86%.
  • The temperature difference between the hottest and cooled cell was about 6°C.


[1] M. Z. S. EL-Dein, M. Kazerani, and M. M. A. Salama, ―Optimal photovoltaic array reconfiguration to reduce partial shading losses, ‖ IEEE Trans. Sustain. Energy Vol.4, No.1, pp. 145-153, 2013.
[2] K. Sundareswaran, S. Peddapati and S. Palani, ―MPPT of PV systems under partial shaded conditions through a colony of flashing fireflies,‖ IEEE Trans. on Energy Convers. Vol. 29, No. 2, pp. 463 – 472, 2014.
[3] M. Saadsaoud , H A. Abbasi, S.Kermiche and M.Ouada, ―Study of partial shading effects on photovoltaic arrays with comprehensive simulator for global MPPT control,‖ International Journal of Renewable Energy Research--IJRER Vol.6, No.2, 2016.
[4] S. Wendlandt, A. Drobisch, T. Buseth, S. Krauterand, P. Grunow, ―HOT spot risk analysis on silicon cell modules,‖ 25th European Photovoltaic Solar Energy Conference and Exhibition /5th World Conference on Photovoltaic Energy Conversion, Valencia, Spain. pp. 6-10, 2010
[5] R. Moretón , E. Lorenzo, L. Narvarte, ―Experimental observations on hot-spots and derived acceptance/rejection criteria,‖ Sol. Energy Vol.118, pp. 28-40, 2015.
[6] Satyendra Vishwakarma, ―Study of Partial shading effect on solar module using MATLAB,‖ International Journal of Advanced Research in Electrical, Electronics and Instrumentation Engineering, Vol. 6, No 7, 2017.
[7] W. He, F. Liu, J. Ji, S. Zhang, and H. chen, ―Safety Analysis of solar module under partial shading,‖ Hindawi , International Journal of Photoenergy, Vol. 2015, 2015.
[8] M. C. A. García, W. Herrmann, W. Bohmer, and B. Proisy, ―Thermal and electrical effects caused by outdoor hot-spot testing in associations of photovoltaic cells,‖ Progr. Photovolt., Res. Appl., vol. 11, no. 5, pp. 293–307, 2003.
[9] J. W. Bishop, ―Computer simulation of the effects of electrical mismatches in photovoltaic cell interconnection circuits,‖ Solar Cells, vol. 25, no. 1, pp. 73–79, 1988.
[10] H. Yang, W. Hu, H. Wang, and M. Narayanan, ―Investigation of reverse current for crystalline silicon solar cells—New concept for a test standard about the reverse current,‖ Proc. 35th IEEE Photovolt. Specialists Conf. (PVSC), USA, pp. 002806–002810, 2010.
Ali. H. Numan et al. Engineering and Technology Journal 39 (09) (2021) 1338-1344
[11] Cl. Buerhop , D.Schlegel , M.Niess , C.Vodermayer , R.Weißmann , C.J.Brabec , ― Reliability of IR-imaging of PV-plants under operating conditions,‖ Solar Energy Materials & Solar Cells Solar EnergyMaterials&SolarCells, Vol. 107, pp. 154–164, 2012.
[12] A. M. Salazar, and E. Queen B. Macabebe, ―Hotspots detection in photovoltaic modules using infrared thermography,‖ MATEC Web of Conferences 7 , 2016.
[13] A. Dolara , G. C. Lazaroiu, E. Ogliari ―Efficiency analysis of PV power plants shaded by MV overhead lines, ‖ Int J Energy Environ Eng. Vol. 7 pp. 115-123, 2016.
[14] M. Dhimish ―Fault detection and performance analysis of photovoltaic installations‖, PhD Thesis, University of Huddersfield, 2018.