On the impact of solar photovoltaic generation on the thermal ageing of transformers

In the last decade, solar photovoltaic energy generation has emerged as one of the leading vanguards of renewable energy source generation in South Africa. The considerable growth in the deployment of solar photovoltaic plants has grabbed the attention of worldwide project developers, investors and stakeholders. In the way indicated, more devised efforts are essential to wield the guarantee that solar photovoltaic plant equipment operate to meet the requirement of solar photovoltaic environment and facilitate the generation of energy as required. One such equipment susceptible to the harmonics and distortion generated by the connected inverters and resonances due to the non-linear loads is the step-up transformer. Harmonics and distortion are well known to introduce additional losses, hotspot temperature rise and reduction of the transformer service life. The rise in hotspot temperature yield abnormal levels of ignitable gases in the step-up transformer oil such that untimely failures may take place. The concentration of this gases suggests partial discharge and excessive heating. Recently reported studies evoke that the designing of solar photovoltaic plant transformers be more robust. This paper intends to contribute additional knowledge towards understanding the adverse effects related to harmonic currents in the step-up transformer for solar photovoltaic application. The winding eddy losses and structural part losses are examined under a harmonic profile to compute the service losses and resultant thermal requirements.