Finally fiber optic sensing of power transformer “Hotspots” is paying off

For nearly 25 years innovative transformer manufacturers, utilities and research organizations such as EPRI have been experimentally installing fiber optic temperature probes in the windings of power transformers. Their quest was motivated by the desire to directly measure the actual winding temperature. These large transformers lose valuable lifetime when the winding temperature exceeds a critical maximum value, even for a few hours during short-term overloads. During this lengthy experimental period the technology started with fragile laboratory equipment, and the inability of transformer designers to accurately identify the location of the hottest-spots in the windings. Today the technology has developed into a mature set of equipment that is hardened to perform in the harsh environment of power apparatus. The equipment is reliable and designers are able to precisely identify hot spot locations in the windings.