Abstract
Grounding systems are essential parts of substations and power generation stations. The evaluation of transferred potentials from an active grounding system to other passive ones or to any near conductors is an important aspect to be considered, because transferred potentials may cause serious and fatal events. Moreover, it is an intrinsic issue of the Smart Grid where the ground systems of the power and ICT systems could be close to each other. Therefore, the estimation of the transferred potential is necessary at grounding system design stage for people safety and electric components safeguard. Numerical methods are the best choice to perform a truthful estimation, especially when large and complex grounding systems have to be designed. However, this task is complicated by the “unbounded” nature of the electromagnetic field and by the presence of components of extremely different size in the analysis domain. In this paper, an efficient hybrid finite element method is applied for the accurate and fast computation of transferred earth potentials from grounding systems. Moreover, the small dimensions of the components in the analysis domain are taken into account by the use of one-dimensional finite elements inserted in the tetrahedral mesh. It is worth mentioning the additional advantage of obtaining the electric potential on the earth surface without any post-processing operation.
Highlights
Grounding systems (GSs) are very important components of electric systems in substations and power plants, as well as in any civil, commercial, and industrial building, because they are essential for human safety [1] and equipment safeguard [2].IEEE Standard 80 and IEC 479-1 establish the body current limits to be met when designing a GS [3].Such limits involve permissible touch-and-step voltages [4], which must be accurately evaluated.The presence of passive GSs, over ground metallic elements, as well as underground ones, in the vicinity of an active GS induces a modification of the electromagnetic field due to the active GS, as well as transferred potentials (TPs) that, in turn, may cause safety issues
This section firstly presents a simple example to verify the accuracy for numerical solution, great distance, the boundary ΓT is constituted by two detached surfaces
This section firstly presents a simple example to verify the accuracy for numerical solution, the computation of TP from an active GS to a near passive one, the problem of TP from a GS
Summary
Grounding systems (GSs) are very important components of electric systems in substations and power plants, as well as in any civil, commercial, and industrial building, because they are essential for human safety [1] and equipment safeguard [2]. When the problem exhibits open boundaries, as in the case of a GS analysis, these methods imply very poor accuracy to computational cost ratios since the discretization of a large domain is necessary in order to obtain acceptable results [29,30] These drawbacks are exacerbated when evaluating the TPs due to the very wide analysis domain to be considered. The hybrid FEM-DBCI numerical method combines the benefits of the FEM and boundary integral methods It has been used for evaluating the GS behavior [17] without considering TPs. in Reference [17] it was presented as an accurate approach to properly consider both the conductivity and the size of each conductor of a GS. It has been combined in this work with the aforesaid hybrid numerical method
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
