High voltage insulation system monitoring and diagnostics: generators, power transformers

During last decades a variety of different practices having the main intention to assess the expected reliability and remaining life span of large units in the power system have been introduced and implemented. During the first period a so called Timely Based Diagnostics (TBD) with a defined periodicity was practiced. Further on the development and introduction of improved testing and measuring methods and tools brought on the Condition Based Diagnostics (CBD). Finally, the Reliability Oriented Diagnostics (ROD) fostered by appropriate methods and tools is practiced by many utilities. The article depicts the most important testing and measuring procedures reported during the last years and particularly those which were long-term practiced in the Milan Vidmar Electric Power Research Institute contributing to an appropriate and efficient asset management.