Presence Of Nearby Buildings Research Articles

Lightning Performance of Overhead Power Distribution Lines in Urban Areas

Buildings nearby urban overhead power lines are expected to reduce the number of direct strikes to the line conductors and also to attenuate the lightning electromagnetic pulse (LEMP) radiated by indirect lightning strokes. The statistical method described in IEEE Std. 1410 for the lightning performance assessment, as the other methods available in the literature, includes only the former effect. In order to take into account also the latter effect, in this paper, the LEMP attenuation due to the buildings is represented by means of specific weighting functions applied to the LEMP analytical expressions valid for open terrain. For both the cases of ideal and lossy ground, the parameters of the weighting functions are identified through the least-square minimization of the differences with the results provided by a finite-element method model that is assumed as reference for the configurations analyzed. The weighting functions can be used for lightning return stroke current waveform and distances between the line and the stroke location different from those used for their identification with reasonable accuracy. Finally, this paper compares the lightning performances of a power line evaluated with and without the presence of nearby buildings.

Lightning-Induced Voltages in the Presence of Nearby Buildings: FDTD Simulation Versus Small-Scale Experiment

In this paper, we have computed lightning-induced voltages on overhead distribution lines in the presence of nearby buildings using the 3-D finite-difference time-domain method. In the simulations, four-conductor lines with surge arresters and pole transformers are considered. It appears that the presence of nearby buildings causes reduction of lightning induced voltages, as expected. The observed trend is in general agreement with that reported from the small-scale experiment by Piantini et al.

Effects of nearby buildings on lightning induced voltages on overhead power distribution lines

For the case of urban overhead lines, the presence of nearby buildings is expected to affect the overvoltages induced by nearby cloud-to-ground lightning return strokes. So far, this effect has been seldom taken into account in the literature on the subject. The paper presents a 3D FEM model that calculates the lightning electromagnetic pulse (LEMP) taking into account the presence of a building placed in proximity of the LEMP-coupled overhead line. As a first approximation, all the metallic elements are assumed as perfect conductors, as well as the ground plane. The calculated fields are then introduced in the Agrawal et al. coupling model for the calculation of the induced voltages. The results of a sensitivity analysis carried by varying the model and dimensions of the building, its distance to the line and the position of the lightning stroke location are presented and discussed.

A Scale Model for the Study of the LEMP Response of Complex Power Distribution Networks

This paper deals with scale models of power distribution systems for the study of lightning induced voltages on overhead lines. The scale model technique is useful for the investigation of situations which are prohibitively complex to be treated theoretically. For instance, urban distribution networks are usually characterized not only by complex topologies but also by the presence of nearby buildings, whose influence on the lightning induced effects can be successfully evaluated by means of reduced models. The paper first describes the scale model implemented for such a purpose at the University of Sao Paulo, Sao Paulo, Brazil. It then presents a comparison between the experimental data obtained with the scale model and the computer simulations obtained by using the LIOV-EMTP code, a software tool able of calculating lightning-induced electromagnetic transients in distribution systems having complex configurations. Finally, the paper shows an application of the scale model in the evaluation of lightning induced voltages on distribution networks considering the presence of nearby buildings