This project is concerned with the development of techniques to identify transformers at risk of catastrophic failure due to the presence of corrosive compounds in the insulating oil. Work will concentrate on further development of techniques to measure corrosive sulphur content in the oil with the aim of producing an on-line data acquisition system that will allow the changes in copper concentration and sulphur concentration to be measured in real-time on in-service plant. The ultimate aim being to develop prognostic tools that can be widely applied to electrical transmission networks to reduce the risk of unplanned outages.