Grounding Analysis in Heterogeneous Soil Models:Application to Underground Substations
Most of the research and development work done until now in earthing analysis is devoted to cases where the soil can be modelled in terms of an homogeneous and isotropic semi-infinite continuous medium, being the soil resistivity an order of magnitude higher than the resistivity of the electrode itself. Furthermore, all formulations of this classical (single-layer) type can be quite easily extended for solving more complex cases in which the soil is stratified in two or more layers of different resistivities. Assuming that the soil is regularized before installing the earthing grid and that the surface is leveled right after (prior to the equipment being assembled and brought into service) this approach is suitable for computing the equivalent resistance and the step and touch voltage in most large electrical overground facilities. This important category includes all step-up and step-down transmission substations, as well as a number of distribution substations indeed. Nevertheless, the current trend in electric power Engineering moves in another direction, due to the growing preference for smaller underground substations as a general rule. This pushes the need for developing new earthing analysis techniques that could be applied to facilities of this kind. In an attempt to do so, we present a mathematical model for earthing analysis in soils with enbedded finite regions of different resistivities. We also present the Boundary Element formulation that we propose for the numerical solution of the resulting equations, which implemention is being considered at present. Finally, we present some preliminary results of the earthing analysis of an underground substation. These results have been obtained by means of an approximated technique which details will be given in forthcoming publications.
grounding analysis earthing analysis underground substations
Ignasi Colominas Jose Paris Xesus Nogueira Fermin Navarrina Manuel Casteleiro
Group of Numerical Methods in Engineering-GMNI Universidade da Coruiia A Coruna, SPAIN
国际会议
三峡
英文
2440-2443
2012-05-18（万方平台首次上网日期，不代表论文的发表时间）