Improved Fiberoptic Temperature Measurement System for Monitoring Winding Temperatures in Medium and Large Transformers

In work carried out over the past five years, the feasibility of using fiberoptic techniques for measuring winding temperatures in power transformers has been demonstrated. The data have been useful in factory performance testing, in checking thermal modeling assumptions and calculations, and in estimating presently unused transformer capacity. The early studies also identified the need for further probe and instrumentation improvements and installation technique simplifications. This paper describes a fiberoptic system designed specifically to meet these needs and describes a cost-effective approach to installation and utilization which should now make practical the general field instrumenting of medium and large transformers.