Influence of the frequency-dependent characteristics of soil permittivity on the impulse performance of grounding electrode

In the analysis of impulse characteristics, the accuracy of the calculation results depends largely on the soil electrical parameters. However, existing calculation methods simplify or ignore the influence of the frequency-dependent characteristics of soil permittivity on impulse performance. On the basis of the dielectric spectrum measurement results of typical soil, a finite element model that considers the frequency-dependent characteristics of soil permittivity is developed in this paper. The influence of the frequency-dependent characteristics of soil permittivity on impulse performance is analyzed systematically. Results indicate that a significant difference exists when the permittivity is constant. The transient grounding impedance value is highly influenced by the impulse current waveforms and the amplitude of the impulse current. (c) 2015 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.