Field experiences with ageing electrical assets in power plants

Electrical assets in power plants, like generators, high-voltage motors, power transformers, power cables, as well as switchgear and their accessories, are all exposed to a variety of environmental and operational stress factors throughout their service life. These stress factors cause ageing and degradation in electrical insulation over time, which can eventually lead to the assets early and unexpected failure. In this paper the operating experience and lessons learned from failure of such aged electrical assets in thermal power plants are discussed. In addition to conducting root-cause analysis related to equipment and system failures, equipment failure investigation are done with a comprehensive understanding of the equipment, experience in its use, knowledge of operation and maintenance practices. The study refers to the present state of condition monitoring in power plants, and problems being faced in carrying out predictive maintenance based on condition monitoring data. Given the above problems, smart condition monitoring techniques are recommended to provide the necessary guidance and the requirements for plant implementation in both the existing fleet and the next generation of thermal power plants.