Multi-point fiber optic sensors for real-time monitoring of the temperature distribution on transformer cores

In this work, a low-cost multipoint fiber optic sensor system for real-time monitoring of the temperature distribution on transformer cores was demonstrated. The temperature sensors are based on multi-mode random air hole fibers infiltrated with CdSe/ZnS quantum dots. Quantum dots resided in multi-mode random-hole core regions can be optically excited by guided UV light with extremely high quantum efficiency. The photoluminescence intensity dependence on the ambient temperatures were used to gauge the local operational temperature of transformer under strong magnetic fields. Multiple point temperature sensing systems were developed by bundling quantum dots infiltrated random air hole fibers together. Using a low-cost UV diode laser as a light source and a CCD camera as detector, hundreds of fiber sensors can be interrogated at low cost. This multi-point fiber sensor system, which is free from electromagnetic interference, was used to monitor temperature fluctuation of transformer from the room temperature up to 96 degrees C with better than 1 degrees C accuracy. The proposed fiber optic sensing scheme could overcome the shortcomings of traditional electric sensors and provide a versatile and low-cost approach to map the temperature distribution of electric power systems such as transformers operated in strong electromagnetic fields.