An Adaptive Chebyshev Approach for Fast Computation of Grounding System Admittance Matrix
The paper proposes an adaptive Chebyshev method for expediting the calculation of grounding system admittance matrix. This facilitates the characterization and the inclusion of the wideband model of the grounding systems into the time-domain electromagnetic transient solvers. In the proposed method, a general electromagnetic approach based on the method of moments (MoM) solution to Maxwell's equations is utilized to obtain the grounding system admittance matrix over the frequency range of interest. Rather than applying the MoM to each distinct frequency obtained from the FFT procedure, the proposed method is utilized to reduce the number of frequency points for which the response of grounding system is calculated. Several simulated case studies are presented to examine the accuracy of the proposed method. It is shown that the selected sampling frequencies are sufficient to generate the exact response of the grounding system over the working frequency interval.