Due to the high mineral contents of additives and enhancement materials (EMs), EMs have become popular in treating soil, which expectedly improves the electrical characteristics of soil. Much of the published work on the effectiveness of EMs is based on investigations at low magnitudes of voltage, current and frequency; however, the study of these EMs under high-impulse conditions has not been widely addressed. In this work, the experimental results of a small-mesh ground electrode without EMs and treated with EMs, where the latter was poured with a controlled amount of water, are presented. The impulse impedance was expected to change appreciably due to the ionic conduction in soil and the use of EMs with a high water content; however, the impulse impedance was found to be weak and dependent on the water content, and the inductive effect was found to be significant at the voltage and current decay times. This indicates that, even though EMs and highly wetted soil can reduce the soil resistivity and relative resistance value, special attention has to be given to the impulse characteristics of the ground electrodes, particularly at tail/decay times.

Regarding the installation of grounding systems, it is not common for the installation site to be re-located due to high soil resistivity. Enhancement materials have been widely used for their known advantages, including their ability to reduce the resistivity of soil. Although some studies have been conducted on the characterization of EMs under AC of various frequencies, limited studies can be found on their performance when mixed with various percentages of water content (WC) and soil. In this work, sand mixed with controlled percentages of enhancement materials (EM 1, EM 2 and EM 3) and controlled amounts of water content was placed on a parallel plate and tested under AC of various frequencies to obtain the resistivity and permittivity. It was found that dry sand–EM mixtures can be represented by an R-C parallel circuit, while wet sand–EM mixtures can be represented by a nonlinear R. These new test data providing the soil resistivity and permittivity of various sand–EM mixtures are important in selecting suitable EMs to be used in grounding systems.

This paper investigates the steady-state resistance (RDC) of copper tape electrodes across eight configurations. The study evaluates both field measurements and simulations using CDEGS at two distinct sites with varying soil characteristics. It emphasizes the impact of electrode size, installation sequence, and soil disturbance caused by sequential installations. Specifically, the results reveal that the first configuration, which maintained a 100% tape-to-trench ratio with no disturbance, yielded computed values within the measured range at both sites. Subsequent configurations demonstrated varying degrees of soil disturbance, affecting RDC values, particularly in high-resistivity conditions. At the low-resistivity Site 1, as the tape-to-trench ratio increased, discrepancies between measured and computed RDC values decreased, highlighting a strong dependency on electrode size and soil cohesion after backfilling. In contrast, at the high-resistivity Site 2, RDC values remained relatively stable with increasing tape-to-trench ratio, likely due to lower soil cohesion and higher air void presence. These findings underscore the importance of considering soil disturbance effects in computational models to enhance the accuracy of RDC predictions and optimize grounding performance.

Many studies have demonstrated that a reduction in ground impedance value occurs under high-impulse current magnitudes, due to the ionisation process in soil. The degree of the ionisation process was found to be influenced by several factors, such as soil resistivity, the ground electrode’s configuration/size, impulse polarity, voltage/current magnitudes and impulse polarity, while in several publications, there was no clear influence of these factors on the ionisation process in soil. Given the uncertainty in the characterisations of grounding systems under high-impulse conditions, it can be difficult to relate the impulse characteristics to the design of grounding systems. This, however, may be possible to achieve if adequate data is obtained, with more tests and analytical studies being performed. Furthermore, as the use of enhancement materials (EMs) has been shown to reduce ground resistance values, the relevant data, which have been found to be limited, are the impulse characteristics of EMs. The effectiveness of these EMs is mostly presented at low-voltage and low-frequency currents, and so far, there is limited available data on their performance with various water contents (WCs) subjected to high-impulse currents. This paper aims to provide the impulse characteristics of soil mixed with various EMs and WCs. Three types of EM were used, and the initial results show that the performance of EMA has an advantage over the others, due to having the lowest Z_imp, current rise and discharge times, and breakdown voltage and times in comparison to other EMs tested in this work.