Citation

El-Harbawi M, Al-Mubaddel F. Sci. Rep. 2020; 10(1): e6295.

Affiliation

Fellow, King Abdullah City for Renewable and Atomic Energy: Energy Research and Innovation Center, (ERIC), Riyadh, 11451, Saudi Arabia.

Copyright

(Copyright © 2020, Nature Publishing Group)

DOI

10.1038/s41598-020-63354-4

PMID

32286453

Abstract

Transformers reduce the voltage from overhead powerlines to voltages acceptable for city/neighbourhood needs. Overheating of transformer cooling fluids presents a serious hazard. In this work, the risk of fires and explosions due to vaporisation of the hydrocarbon components of mineral oil, which is used as a transformer cooling fluid in electrical substations, was investigated. The compositions of new and used mineral oil from an electrical substation in Riyadh were analysed using gas chromatography-mass spectrometry, and C₆ to C₄₁ hydrocarbons were detected. The majority of the components were alkanes, alkenes, or alkynes; some ketone, alcohol, aromatic, and anhydride species were also detected. Approximately 25% of the compounds comprising the new oil sample were alkanes, whereas more than 33% of the used oil sample components were alkanes. The lower and upper flammability limits (LFL and UFL) of the mixtures were found to be 0.88 and 5.75 vol.% for the new oil and 0.47 and 3.05 vol.% for the used oil, respectively. These values were used to construct a flammability diagram. The results indicated that the new and used oil vapour mixtures were not flammable at 25 °C and 1 atm, but would become flammable at 77 and 115 °C.

Language: en