Study of molecular behavior in oxidation of insulating oil using terahertz spectroscopy

Abstract

The stock of aged power equipment is increasing and it is important to clarify the characteristics of deteriorated insulating oil. This paper describes a basic study of molecular behavior in the oxidation of insulating oil by terahertz spectroscopy. The oxidation of insulating oil was modeled by using various compositions of dodecane and 2‐octanol. The terahertz measurements indicated that significant absorption related to hydroxyl groups (‐OH) occurred between 6 and 7 THz. The absorption band was also observed in accelerated aging alkylbenzene, which is used in power equipment as insulating oil and is sensitive to hydrogen bonds. © 2013 Wiley Periodicals, Inc. Electr Eng Jpn, 183(1): 9–15, 2013; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/eej.22335

Industrial Applications of Terahertz Sensing: State of Play

“…Employing THz sensing to detect oxidation products—carbonyl and hydroxyl compounds—in oils is an effective technique, because those compounds are strongly polar and therefore strongly THz absorbing, allowing detection at low concentrations. A number of studies have been performed demonstrating high sensitivity and good discrimination of such measurements (Figure 22) [159,160,161,162,163,164,165]. Contamination by water can also be a cause of oil degradation, especially in engine oils where water is a product of fuel burning, and where sensitive THz detection has been demonstrated [165,166].…”