Analysis of Core Losses in a Three-Phase Distribution Transformer Under Reverse Power Flow Using the Finite Element Method

Photovoltaic generation is rapidly expanding, especially in small-scale residential and commercial installations, also known as distributed photovoltaic generation. An important aspect of this energy source is its intermittent generation. Power can only be injected into the grid when the solar panels are exposed to sunlight. Thus, a novel power flow pattern has emerged within the grid, in which excess generation results in a reverse power flow, that goes through the transformer towards high voltage. To attain a deeper comprehension of this phenomenon’s impact on the distribution transformer, particularly in relation to its core losses, this study develops a methodology that includes the analysis of balanced reverse power flow scenarios. Additionally, a simulation model is developed using the Finite Element Method in Ansys Electronics® software, and the results are analyzed. Based on this analysis, it can be concluded that reverse power flow increases core losses in the transformer compared to conventional power flow, although this effect is highly dependent on the equipment characteristics.