Combined molecularly imprinted polymer and surface plasmon resonance transduction in plastic optical fiber for monitoring oilfilled power transformers

In this work the feasibility of an optical method for an early and high sensitivity detection of chemical agents in oil-filled power transformer is reported. It concerns the assessment of accelerated ageing of transformer insulating systems, primarily constituted of oil, paper and cellulose through an online detection of cellulose degradation by-products. The proposed optical device exploits the Surface Plasmon Resonance (SPR) excitation in a plastic optical fiber (POF) platform. High selectivity is obtained by a joint detection with a Molecularly Imprinted Polymer (MIP) layer, very specific for one of the most significant indicators of the transformer possible failure, furfural, in contact with the SPR active surface. Preliminary results of tests, carried out on calibrated furfural concentration diluted in transformer oil, confirm the feasibility of the proposed optical approach.