Investigations on the Performance of Grounding Device with Spike Rods (GDSR) with the Effects of Soil Resistivity and Configurations

Abstract

<jats:p>In a recently published work, the characteristics of a new grounding device with spike rods (GDSR) with various arrangements of ground electrodes under high magnitude impulse currents (up to 16 kA), was investigated. In an earlier study, the ground electrodes were installed in low resistivity test media, with resistance at steady state (Rdc) values ranging from 11 Ω to 75 Ω. In practice, various soil resistivity, ranging from a few Ohm-metres to several kiloOhm-metres, have been reported in the standards. It is, therefore, necessary to investigate the characteristics of GDSR with different arrangements of ground electrodes in various soil resistivities under high impulse currents. In this present paper, six configurations of ground electrodes are used, installed at three different sites and subjected to high impulse conditions. Impulse test data of all the grounding systems are analyzed. The Finite Element Method (FEM) is used to compute the electric field values of the ground electrodes achieved. It is found that the highest electric field occurs in the presence of electrodes with the highest Rdc, soil resistivity and current magnitudes. This new data would be useful in bolstering the performance of GDSR in various types of soil resistivities, electrode arrangements and current magnitudes, which may allow for optimum design of grounding systems.</jats:p>

Influence of Lightning Current Parameters and Earthing System Designs on Tower Footing Impedance of 500 kV Lines

“…When developing a TL, tower footing resistance is one of the important parameters to be considered. The outcome of the improvement in the TFR depends on many factors, including the earth structure and soil resistivity, among others [15][16][17][18][19]. The arrangement of the earthing design usually has a relationship with the form of the configuration or tower footing.…”

Impulse Characteristics of Ground Electrodes in Low Resistivity Soil

“…Along with these parameters of impedances, current rise and discharged times have also been analyzed and presented for various electrode's configurations and impulse polarity [6][7][8][9]. Current rise time is defined as the time taken for the current to reach its peak value, while the current discharged time is the time taken for the current to discharge to ground.…”

“…Current rise time is defined as the time taken for the current to reach its peak value, while the current discharged time is the time taken for the current to discharge to ground. It was discussed in the field experimental work [4,7,10] that the current rise times are an indication of the presence of inductive effect in the ground electrode, and were studied for a range of configurations, soil resistivity and stress. Harid et al [4] found that the longer the vertical rods and horizontal electrodes, the slower the current rise times were.…”

“…Another main parameter that has not been well addressed in analyzing the soil characterisation particularly by laboratory approach is the current discharged times. In the recent years, several studies measured the current discharged times by field measurements under the influences of soil resistivity, ground electrode's configurations and impulse polarity field [6][7][8][9]. Ref.…”

“…The current discharged times are also found to be dependent on the voltage/current magnitudes, where faster current discharged times are seen at higher voltage/current magnitudes in their studies. Abdul Ali et al [7] observed that the current discharged times are faster/lower for larger ground electrode's configurations, hence its steady state resistance values, R DC , indicating an effective grounding system for large ground electrodes.…”