Search results for "Earthing"
showing 5 items of 35 documents
Results of the research on global earthing systems: A contribution to the problem of their identification
2013
The paper presents a study on the factors that can have influence on the rise of a Global Earthing System. The first part of the work deals with: - the definition of proximity, interconnection and quasi-equipotential; - the influence of the presence of HV/MV stations on the dangerous voltages and on the permissible voltage limits; - the dependence of the hazardous condition for persons on the different kind of fault; - the effects on safety of the coexistence of HV, MV and LV systems. In the second part, starting from the discussion on the themes above-mentioned and on the results of the studies, measurement campaigns and simulations on interconnected earthing systems done in the last fifte…
Earthing System's Design in presence of non-uniform soil
2007
The Authors propose a practical approach for facing the problem of the design of the earthing systems in two-layer soils. The approach is based on the calculation of an equivalent resistivity of the non-uniform soil through which the designer can treat this one as it was uniform. The purpose of the Authors is to provide an innovative simple method and some easy-to-use graphs for an easy earthing systems’ design in two-layer soils.
Earth resistance measurements in urban contexts: Problems and possible solutions
2017
Both EN 50522 and IEEE Std. 81 propose the Fall of Potential Method (FPM) to carry out the measurement of the resistance to earth of an Earthing System (ES). However, in urban areas, the recommended distances between the ES and auxiliary electrodes are not easy to respect, due to the presence of buildings and tarmac. Moreover, unknown buried metallic parts, as well as the interconnection among the ESs made by the Distributor System Operator, could modify the earth potential profile of the area, affecting the measurement results. In this paper, the issues that could affect the measurement result if FPM is used in an urban context are presented. A parametric analysis, carried out with Comsol …
Considering safety issues in minimum losses reconfiguration for MV distribution networks
2009
This paper offers a new perspective over the traditional problem of the multiobjective optimal reconfiguration of electrical distribution systems in regular working state. The issue is indeed here formulated including also safety issues. Indeed, dimensioning the earth electrodes of their own secondary substations, distribution companies take into account the probable future configurations of the network due to transformations of overhead lines into cable lines or realization of new lines. On the contrary, they do not consider that, during normal working conditions. the structure of the network can be modified for long periods as a consequence of reconfiguration manoeuvres, with differences …
A study of the behaviour of earth electrodes connected together in resonant earthed neutral systems
2005
Inside urban areas the earth electrodes of the MV/lv substations are often electrically connected together so as to form a single extended earthing system. The advantages of the realization of an extended earthing system are the reduction of the current that each substation earth electrode injects in the soil during the fault and a better uniformity of the voltages to earth inside the urban area. In previous works, models for the study of extended earthing systems have been proposed. These models were valid for the case of single-line-to earth fault in isolated neutral MV networks. In this paper, the extended earthing system is analyzed in the case of a resonant earthed neutral MV network. …