Power Transformer Design Implementation for Large-Scale Solar Power Plant Grid Integration

South Africa is currently facing shortage of electricity, as the national utility is forced to implement routine load shedding stages. To tackle this problem, the country has planned to boost its electricity infrastructure through the systematic development of renewable energy independent power projects to provide additional capacity for the national grid. In this study, the design of a 60 MVA 88/33 kV YNd1 power transformer is implemented for a solar photovoltaic (PV) plant. The power transformer is designed and tested at SGB-SMIT POWER MATLA. The transformer is designed using an in-house transformer design system (TDS) to predict the performance. The transformer is then manufactured, tested and successfully installed on site. The factory acceptance tests (FAT) on thermal and short-circuit, as well as conducted no-load, load and short-circuit impedance tests confirmed the transformer specifications and suitability for the proposed project. The specified impedance is 11 % which is the same as the measured impedance, the former is over by 0.2 % to cater for internal production tolerances that have been experienced over the years.