Diagnostic methods for transformers

In electrical networks are power transformers as interface between different voltage levels of essential importance. Due to the long manufacture process they are one of the most critical and expensive equipment and so this is one of the reasons why condition monitoring becomes more popular. Monitoring systems as basis for diagnostics open the possibility for expanding the operating time, reducing the risk of expensive failures and allows several maintenance strategies. With different monitoring techniques detailed information about the transformer condition can be received and helps to minimize the probability of an unexpected outage. As a traditional monitoring and diagnose techniques for transformer condition is the periodic sample of the transformer oil and to carry out a dissolved gas analysis. This paper gives an overview about different monitoring and diagnostic methods and techniques. With these systems significant parameters are recorded. Based on these measured variables conclusions of the future behaviour of the technical resources can be made. New developments in the area of signal measuring and conditioning, data processing and analysing as well as environmental aspects make a more precise and detailed condition evaluation possible.