Análise de perdas e aquecimento em enrolamentos de transformadores para sistemas fotovoltaicos sob ação de harmônicas: uma abordagem numérica axissimétrica e experimental

• Ano de defesa: 2025
• Autor(a) principal: Perin, João Pedro Pranke
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Santa Maria; Brasil; UFSM; Programa de Pós-Graduação em Engenharia Elétrica; Centro de Tecnologia
• Palavras-chave em Português: Transformadores; Harmônicas de corrente; Geração fotovoltaica; Simulação numérica; Transformers; Current harmonics; Photovoltaic generation; Numerical simulation; CNPQ::ENGENHARIAS::ENGENHARIA ELETRICA
• Link de acesso: http://repositorio.ufsm.br/handle/1/36720

Power transformers connected to photovoltaic power plants operate as step-up devices, enabling the dispatch of the generated energy to the transmission system. However, the presence of inverters in these systems can introduce high-order harmonics, whose interaction with the grid may result in resonances that affect transformer performance, especially in terms of losses and heating. This work presents a numerical and experimental investigation on the impact of current harmonics on power losses and temperature rise in windings of transformers subjected to a typical harmonic spectrum found in photovoltaic plants. The numerical analysis is conducted through coupled Finite Element Method simulations, considering both magnetic and thermal effects, with a focus on the windings and the electrostatic shield of a 9.1 MVA transformer applied to photovoltaic systems. In parallel, an experimental study was carried out using a 10 kVA single-phase distribution transformer subjected to the same harmonic spectrum. The results show that winding losses increase approximately quadratically with the harmonic order, highlighting the impact of harmonic distortion on the magnetic performance of the equipment. However, the resulting temperature rises, under typical operating conditions, were not significant enough to individually represent a direct threat to the service life of the analyzed transformers. Therefore, this study suggests that the impact of harmonics on temperature may not be the main factor associated with the observed reduction in service life of transformers connected to photovoltaic inverter systems. The adopted methodology, which combines numerical analysis with experimental validation, proved effective and can be applied to different transformer configurations and harmonic spectra, contributing to a deeper understanding of the behavior of these devices in harmonic-distorted environments.