Distributed Real-Time Temperature Rise Monitoring of Transformers (Conference Presentation)

Abstract

Real-time temperature mapping that solves local overheating problems is important for obtaining an optimized thermal design for high-efficiency power transformers. Internal temperature monitoring of operating power transformers can also be leveraged for asset monitoring applications targeting at-fault detection enabling condition-based maintenance programs. However, transformers present a variety of challenging sensing environments such as high-levels of electromagnetic interference and limited space for conventional sensing systems in which to operate. Immersion of some power transformers in insulation oils for thermal management during operation and the presence of relatively large and time varying electrical and occasional magnetic fields make sensing technologies requiring electrical wires or active power at sensing locations highly undesirable. In this work, we investigate dynamic thermal response of a standard single-mode optical fiber instrumented on compact transformer cores by using an optical frequency-domain reflectometry scheme. Correlation between conventional temperature sensing methods and fiber-optic sensing results as well as trade-offs between spatial resolution and temperature measurement accuracy is discussed and spatially resolved real-time monitoring of temperatures in energized transformers is demonstrated.