Citation

Aman, Fazlul (2026) Electrical characterization of soil-enhancement material for grounding systems under AC and impulse conditions. Masters thesis, Multimedia University.

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Abstract

A large part of the reliability and safety of the power networks depends on the grounding systems, where resistivity of the soil and ground electrodes become important aspect of the grounding systems. The sites where high-resistivity soils are predominant, grounding effectiveness is often improved by the use of enhancement materials (EMs). Despite extensive application, the behaviour of soil-EM mixtures to various electrical stresses is not adequately defined especially when subjected to low magnitude alternating currents (AC) and high voltage impulse conditions. This thesis fills such gaps by a thorough laboratory study of the electrical properties of soil-EM mixtures at predetermined proportions of EM and water content (WC). The AC tests (50 Hz-20 kHz) indicated that it was possible to model the dry sand-EM mixtures with a nonlinear resistive-capacitive circuit, where the resistivity would drop significantly with increasing frequency, reaching approximately 1.5 MΩm at 20 kHz. The wet mixtures were found to be mostly resistive with a steady state average resistivity in the range of 1.42-1.49 MΩm. Under high-voltage impulse tests, EM treatments caused significant improvement in the conduction properties, with the resulting impulse impedance (Zimp) decreasing up to 98% from plain sand. This improvement in conduction, however, decreased the breakdown threshold in transient conditions: for carbon-rich materials (EM1 and EM2), this reduction was between 46% and 55% (from 10.6 kV/cm in plain wet sand to around 5.4 kV/cm), and the times to breakdown (tD). In addition, polarity dependent tests showed that the positive impulses tended to have greater Zimp and E50 values compared to the negative impulses. Interestingly, this polarity sensitivity was greatest in low moisture media, but was significantly reduced in highly wetted, EM-rich media, where impedance differences were less than 1%.The results indicate the advantages and limitations of EMs: they, on the one hand, significantly reduce the resistivity of the soil and the resistance of the ground; on the other hand, they reduce the breakdown thresholds in transient conditions. This work will contribute to a better understanding on the conduction and breakdown processes of soil-EM mixtures, and it will provide practical implications on material selection, grounding design, and equivalent circuit modelling in high-voltage protection systems. This finding will also be helpful to ensure that grounding processes are safer and more reliable, especially in high resistivity conditions.

Item Type:	Thesis (Masters)
Additional Information:	Call No.: TK3227 .F39 2026
Uncontrolled Keywords:	Electric currents—Grounding
Subjects:	T Technology > TK Electrical engineering. Electronics Nuclear engineering > TK3001-3521 Distribution or transmission of electric power
Divisions:	Faculty of Artificial Intelligence & Engineering (FAIE)
Depositing User:	Ms Nurul Iqtiani Ahmad
Date Deposited:	05 Oct 2026 01:11
Last Modified:	05 Oct 2026 01:11
URII:	http://shdl.mmu.edu.my/id/eprint/16849

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