Pulsed amperometric detection of furan compounds in transformer oil Original Research Article

The failure of high voltage transformers can result in significant cost and supply implications to both power supplier and consumer alike and in extreme cases may result in explosion, serious injury or death. Transformer failure can be predicted by measuring furanics present in the oil, produced by the thermolytic breakdown of cellulosidic insulators. Failing units can have furanic levels of up to 10 μg ml−1. The use of pulsed amperometric detection (PAD) to measure furanics in transformer oils in real time is reported here. Oils were examined by pre-extraction or direct suspension in aqueous measurement solution or by solubilisation and direct PAD measurement in organic solvents. Linear relationships between PAD response and furanic concentration was found for 2-furaldehyde and furfuryl alcohol (F-OH) across the range of 0–10 μg ml−1, with PAD proving most sensitive to the latter compound. PAD was performed directly in the organic phase in t-butanol with 0.1 M tetramethyl ammonium hydroxide, with aged oils containing >2 μg ml−1 of 2-furaldehyde yielding data within close agreement (<9%) of a standard chromatographic method. The simplicity and rapidity of this method offers the power transmission industry a means of monitoring furanic levels in transformers in real time, thereby reducing the risk of uncontrolled transformer failure.