The use of optic fibres for temperature monitoring in power transformers

A knowledge of the hot-spot temperature in a power transformer is a key element for its design and utilisation. It enables manufacturers to refine their design, improve the quality and competitiveness, and users to utilize the full overload capacities of transformers and hence meet requirements of their customers without excessively reducing life expectancy of equipment. Fibre optic technology offers an opportunity for direct hot-spot measurement without any detrimental effects to the dielectric integrity of the transformers. Measuring instruments are available as well as information on successful tests. Field experience is still limited. Here, the author briefly addresses some specific aspects of installation of fibre optic temperature measuring systems in power transformers and summarises some experience gained during the successful installation and testing of such a system in Peebles Power Transformers factory in Edinburgh