Analysis and Design of a Special Type Power Transformer Used in Solar Power Plants

Due to growing of greenhouse gas emissions and lack of the fossil sources, governments encouraged all scientists and utilities for looking to the alternative energy sources such as solar renewable energy which can help to reduce carbon dioxide emissions. In this respect, Photovoltaic (PV) power plants have become more important in recent years and renewable energy sources integrated into the power system are increasing day by day. Transformers are the main components of electrical grids and are widely used in renewable power plants to transfer the energy they produce to the grid. Accordingly, transformers are one of the most critical equipment of PV plants, and their safe operation and stability in the electrical network are important. This type of transformer is supplied from solar panels through inverters and needs to be customized to work with each system. In this type of transformer, the losses are higher than those for transformers used in electrical power systems supplied by sinusoidal voltage considering existence of different voltage and current harmonics content produced by the inverter. In this study, a special type of PV transformer was designed in accordance with the target performance criteria, taking into account the effects of harmonics, and keeping the transformer losses and temperature rise at a safe level. In this paper also the simulation results are compared with those of experiments test to verify the design procedures.