Frequency analysis of grounding systems

Abstract

As it is known, an effective grounding system must exist in any substation to ensure adequate safety for people and to protect the installation. The objective of a grounding system is to provide a way to ground for currents generated by some fault or disturbance. The circulation of these currents in the ground produces voltages between different points of the earth that may be dangerous for people. In this work, a methodology to analyze the behavior of grounding systems fed by harmonic currents is proposed. The model is based on the electric circuit theory approach, and it is solved by means of conventional analysis techniques. Multiple cases were studied and compared with other methods and high agreement was obtained for frequencies up to 1 MHz. Although the problem is treated in the frequency domain, the response for currents of any other shape (e.g. lightning) is obtained by means of the Fourier transform technique.