Grounding system models for electric current impulse

Abstract

In this paper, two electrical models that simulate grounding system responses to current impulses with inductive or capacitive characteristics are presented. The models were elaborated from the analysis of voltage–current curves obtained from field tests. The characteristic curve of the relation between measured voltage and applied current (V×I) was used to identify the electric circuit model elements. In order to evaluate the proposed models, two grounding system configurations applied in electrical system and an additional configuration presented in the literature were used as case study. For each configuration, two models were evaluated: the proposed model and a literature model. The results of the proposed and literature model were evaluated and compared using calculated error statistics over time. The proposed model application resulted in values of total effective error lower than 5% in all analyzed cases, with equivalent error index values regarding the literature model and, in some cases, even smaller. The proposed model has more advantages in comparison to the literature model, since it has fewer and only linear elements. Due to the presentation of a simple and reliable configuration, the proposed circuits can be coupled, with greater ease and flexibility, to transient analysis programs and in insulation coordination studies.