In my internship at SA Power Networks I was part of the Substation Asset Engineering Team. A major part of what we do is taking care of everything inside the fence of a substation - this encompasses everything from the transformers, circuit breakers and even the non-electrical parts like the buildings. The main project I was involved with was an investigation into transformers. A certain family of transformers had experienced several of the same mode of failure. The projects’ goal was to investigate these failures and try to predict which ones were at risk of failing next, to better inform decisions like maintenance, replacement and investment. The ones I looked at were power transformers that stepped down voltage to power feeders. This project is important because transformers are an essential, necessary part of the electricity network, and without them customers would lose power. Throughout the project, the method of investigation evolved as we found out more information. Fault current modelling, reading outage reports, and collecting historical fault data were all done to get a history of each transformer’s service life. I researched into the construction, operation and design of transformers to get a better understanding of the failure mode. One challenge was the sheer amount of data this investigation required, given the quantity of them in service and the duration they had been in service. Some of the data required were not of high quality, like faults from a couple of decades ago when sensors and data acquisition systems were not as common or advanced as they are today. The project gave me a better appreciation into why and how decisions like prioritising certain maintenance jobs in a schedule are made. Power transformers, like other parts of the electricity network, have a great cost, so any decision such as replacement should be made with confidence, and the data to back up that decision, to make the most effective use of the budget. It also made me realise that work done now could have strong impacts on the future, even looking 10+ years ahead. I had several site visits which included me looking at different types of power transformers. The people around me in my team I found to be extremely knowledgeable, with strong practical experience, and were always willing to give me a hand. Overall, I had a great experience during this internship, learning a lot and getting to contribute to meaningful work, so I am keen for a future within the power industry.