Dielectric properties of sunflower, rapeseed and commonly used mineral oil

• Published in: 2016 17th International Scientific Conference on Electric Power Engineering (EPE) pp. 1 - 4
• Main Authors: Ulrych, Jiri, Mentlik, Vaclav
• Format: Conference Proceeding
• Language: English
• Published: IEEE 01.05.2016
• Subjects: commonly used mineral oil; complex permittivity; conductive component; dielectric spectroscopy; Frequency measurement; Minerals; Permittivity; Permittivity measurement; rapeseed oil; relaxation processes; sunflower oil; Temperature measurement; Vegetable oils
• DOI: 10.1109/EPE.2016.7521753

This paper deals with analyses of chemical structure and real and imaginary parts of complex permittivity of sunflower, rapeseed and commonly used mineral oil. The sunflower and rapeseed oils measured are natural ester molecules with a triacylglycerol structure and have mainly very good fire resistance and biodegradability. The measured commonly used mineral oil is a mixture of hydrocarbons produced from crude oil and belongs to the group of naphthenic oils consisting mainly of cycloalkanes. It is rather inflammable and dangerous for living environment. The measurement was performed by means of the dielectric spectroscopy method. The real and imaginary parts of complex permittivity were analyzed at frequencies from 5 mHz to 0.5 MHz and within the temperature range from -50 °C to 90 °C. The measured spectrums displayed conductive component as well as relaxation processes. The results showed that the measured dielectric properties of the investigated vegetable oils were similar to each other in the evaluated temperature range, but different from the commonly used mineral oil properties. The properties of the commonly used mineral oil were much better than those of the sunflower and rapeseed oils. The research of insulation liquids should aim at searching oils with insulation properties similar to properties of mineral oils and fire resistance and biodegradability similar to vegetable oils.