ELECTRICAL AND GEOTECHNICAL PROPERTIES OF SOILS AROUND ELECTRICAL POWER TRANSFORMERS

¹Odoh, F.E., ¹Asibeluo, U.N. and ^2*Akpokodje, O.I.

¹Department of Electrical Engineering, Delta State University of Science and Technology, Ozoro, NIGERIA

²Department of Civil and Water Resources Engineering, Delta State University of Science and Technology, Ozoro, NIGERIA

*corresponding author: akpokodjeo@gmail.com

ABSTRACT

Geophysical investigation of the soil was embarked upon in this research, to evaluate the effects of power transformer oil spill on the immediate environment. The impact of electrical transformer oil on the soil’s heavy metals content (lead “Pb”, Cadmium “Cd” and zinc “Cd), geotechnical properties (Atterberg limits) and electrical resistivity, were determined using standard procedures. Findings obtained from the laboratory tests signified that the oil significantly increased the soil’s Pb, Zn, Cd content, and the soil’s electrical resistivity. Remarkably, the soil liquid limit “LL”, plasticity index “PI” and plastic limit “PL”, declined in an uneven pattern with an increase in oil pollution rate. In the soil specimens sampled from the vicinities of the transformers, the Cd content ranged from 0.23 – 1.42 mg/kg, Pb content ranged from 21 – 35 mg/kg, and Zn concentration ranged from 17 – 36 mg/kg. It was also observed from the contaminated soil samples that LL values varied from 40.51 – 53.63%, PL values ranged from 19.88 – 23.88%, and the PI values varied between 19.7 and 32.32%; while the control site’s soil had LL, PL and PI values of 59.23%, 25.27% and 28.96% respectively. Regarding soil electrical resistivity, the transformer oil impacted soil samples developed resistivity that varied from 374 Ωm to 877 Ωm; which were higher than the resistivity value of 284 Ωm recorded for the reference point’s soil. The increase in the soil resistivity of the contaminated soil, poses a momentous threat to the transformer’s grounding structure. Results obtained from this research revealed the necessity for regular monitoring of the electrical distribution installations to enhance their working conditions.

Keywords: Electrical installation, health hazards, heavy metals, oil pollution, soil properties.