Research on the transformer oil-based nanofluids (NFs) has been raised expeditiously over the past decade. Although, there is discrepancy in the stated results and inadequate understanding of the mechanisms of improvement of dielectric nanofluids, these nanofluids have emerged as a potential substitute of mineral oils as insulating and heat removal fluids for high voltage equipment. The transfo...

The winding hot-spot temperature is one of the most critical parameters that affect the useful life of the power transformers. The winding hot-spot temperature can be calculated as function of the top-oil temperature that can estimated by using the ambient temperature and transformer loading measured data. This paper proposes the estimation of the top-oil temperature by using a method based on ...

A method was developed to analyze the distribution of sulfur compounds in model sulfur compounds by potentiometric titration, and applied to analyze hydrotreated transformer base oil. Model thioethers were oxidized to corresponding sulfoxides by tetrabutylammonium periodate and sodium metaperiodate, respectively, and the sulfoxides were titrated by perchloric acid titrant in acetic anhydride. T...

The measurement of oil-paper insulation systems in the frequency domain provides novel diagnostic methods for quality control of materials and highvoltage power transformers. The first task is to measure and to analyse the dielectric behaviour of oil-paper insulation systems and their dependency on material quality, moisture content and ageing products in oil, paper and pressboard. Furthermore,...

Development and modifications are described that expand the application of an immunoassay from the detection of Kanechlors (Japanese technical PCBs mixtures) to the detection of Aroclors (U. S. technical PCB mixtures, used in Korea) in contaminated Korean transformer oil. The first necessary modification was the development of a new antibody with a reactivity profile favorable for Aroclors. The...

Conjugate heat transfer problem of a disc winding in a power transformer is studied using commercial CFD software. The study is done for oil flow, temperature distribution, hot spot location and temperature of the winding, for three different cases: first, no oil leakage past the top washer; second, partial leakage due to a 2 mm gap between the top oil guiding washer and cylindrical pressboard;...

Reliability of electrical energy networks depends on quality and availability of electrical equipment like power transformers. Local failures inside their insulation may lead to catastrophic breakdowns. To prevent destroying events power transformers are e.g. tested on partial discharge (PD) activity. As testing is just snapshot information about transformers condition, permanent online monitor...

A potential degrader of paraffinic and aromatic hydrocarbons was isolated from oil-contaminated soil from steel plant effluent area in Burnpur, India. The strain was investigated for degradation of waste lubricants (waste engine oil and waste transformer oil) that often contain EPA (Environmental Protection Agency, USA) classified priority pollutants and was identified as Ochrobactrum sp. C1 by...

An overview of the research and developments into new transformer design, undertaken in the Department of Electrical and Computer Engineering, University of Canterbury, is presented. Initially, single phase, 50 Hz, l1/0.23kV pole mount distribution transformers were fitted with either silicon or amorphous steel cores. The transformer tanks were filled with either standard transformer oil or liq...