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International Journal of Renewable, Green, and Sustainable Energy

Open Access Peer Review International
Open Access

IMPACT OF PHOTOVOLTAIC-INDUCED HARMONICS ON DISTRIBUTION TRANSFORMER HOTSPOT TEMPERATURE: AN ELECTRO-THERMAL MODELING APPROACH

DOI https://doi.org/10.55640/
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Dr. Elena Petrova 1 , Dr. Ahmed F. El-Sayed 1 ,
4 Power Systems and Renewable Energy Research Lab, Moscow Power Engineering Institute, Moscow, Russia
4 Department of Electrical Power and Machines, Cairo University, Giza, Egypt

Abstract

The increasing integration of photovoltaic (PV) systems into low-voltage distribution networks introduces power quality concerns, particularly due to current and voltage harmonics. These harmonics can lead to increased thermal stress in distribution transformers, potentially reducing their operational lifespan. This study presents an electro-thermal modeling approach to evaluate the impact of PV-induced harmonics on the hotspot temperature of oil-immersed distribution transformers. A detailed harmonic load profile was developed based on real PV generation data and inverter characteristics. The model couples electrical harmonic analysis with thermal simulation using IEEE and IEC transformer thermal models. Results indicate that the presence of high-order harmonics, especially during peak PV output hours, can cause a hotspot temperature rise of up to 8–12 °C compared to harmonic-free operation. This elevated temperature can accelerate insulation aging and compromise transformer reliability. The study highlights the need for harmonic mitigation strategies in PV-rich grids and supports transformer design optimization for harmonic resilience.

Keywords

Photovoltaic systems, harmonics, distribution transformer

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