Symmetry exploitation to reduce impedance evaluations in grounding grids

• Published in: International journal of electrical power & energy systems 2020-12, Vol.123, p.106268, Article 106268
• Main Authors: Vieira, Pedro H.N., Moura, Rodolfo A.R., Schroeder, Marco Aurélio O., Lima, Antonio C.S.
• Format: Article
• Language: English
• Subjects: Electromagnetic analysis; Frequency response; Grounding; Method of moments; Numerical methods; Symmetry
• ISSN: 0142-0615; 1879-3517
• DOI: 10.1016/j.ijepes.2020.106268

•Modeling of several grounding systems including single conductors and symmetrical grounding grids.•Identification of symmetries to improve the evaluation of the impedance matrix of grounding grids without loss of accuracy.•Improvement of numerical efficiency of grounding grid impedance evaluation algorithms.•Enhancements on the transient analysis of grounding grids.•Adequacy of the proposed formulation via comparison with actual grounding system configurations. One main concern on wideband evaluation of grounding systems is the high computational burden related to the determination of the impedance matrices. Traditionally, one has to divide any given conductor in a large number of segments which leads to a rather time consuming procedure. However, there are a number of geometrical symmetries that if exploited can significantly reduce the overall computational time. This work aims at investigating the adequacy of using some existing symmetries to reduce computer burden in the assessment of a wideband grounding system in models based on the Method of Moments. An algorithmic approach is proposed to extend the symmetry exploitation to arbitrarily oriented uniform rectangular grounding systems. Several topologies are used to assess the performance of the proposed approach. According to results, the proposed methodology can be more than 12 times faster than the traditional approach without loss of accuracy because it is not a numerical approximation.