Earth Grid Design for 400KV Neiuwehoop Substation Using CDEGS Platform

Abstract

The earth grid design for substations is pivotal for substation design, particularly in high resistivity soil where resistance on the lowest layer is greater than the upper gradation soil. In this paper, a 400kV Neiuwehoop substation earth grid design is presented using Current Distribution Electromagnetic Field Grounding Soil Structure Analysis Software (CDEGS) platform. The four-electrode Wenner method is used to determine the soil resistivity distribution. For an estimated single-phase system fault current of 40kA at 0.5second, the touch potential design of $0 \Omega$ and the foot resistance of $0.5\mathrm{k} \Omega$ are determined. The step potential of 262.6V and touch potential of 186.5V is found. The ground potential rise of 15.942kV relatively correlates with the calculated as well as measurements obtained.