Highly Sensitive Plasmonic Sensor for Moisture Detection in Transformer Oil Using Silver-Coated D-Shaped Optical Fiber

Transformer oil plays a critical role in maintaining the insulation and cooling functions of power transformers. However, its performance is significantly affected by moisture contamination, which reduces dielectric strength, accelerates material degradation, and increases the risk of catastrophic failures. This study presents a highly sensitive and cost-effective optical sensing device based on a D-shaped optical fiber coated with silver nanoparticles (Ag-NPs) to detect moisture levels in transformer oil. The sensor makes use of plasmonic homes of Ag-NPs to expand sensitivity and affords real-time moisture detection with a decrease detection restriction of 15 ppm. Fabrication of the sensor became carried out through electron beam evaporation, and its overall performance was optimized the usage of advanced simulations, inclusive of finite detail evaluation and the Drude model. Experimental effects confirmed a sturdy correlation between moisture degrees and transmitted strength changes, demonstrating a sensitivity of 0.4097 dB/ppm. Comparisons with conventional strategies, which include Karl Fischer titration and capacitance sensors, suggest that the proposed sensor gives superior accuracy, quicker reaction times, and lower fabrication charges. These findings underscore the capability of this sensor for enhancing transformer protection strategies and stopping operational failures.