Impedância de Surto de Sistemas Elétricos Constituídos por Múltiplos Condutores Verticais
Keywords: Surge Impedance, Transmission Towers, Jordan’s Formula, Lightning, Neumann’s Integrals
AbstractTransmission towers are an essential component for the functioning of a country’s electrical system. In countries with a large extension of transmission lines and a high incidence of lightning, problems related to the interaction between lines and lightning are quite intense. Thus, it is of fundamental importance to develop models that compute the response of the transmission system when an electromagnetic transient is established. This article aims to present the revised Jordan formula for calculating the surge impedance of a vertical conductor, and its extension to calculate the surge impedance of multiple vertical conductors. Neumann integrals are also applied to calculate the self and mutual surge impedances of vertical conductors. The results of surge impedances, of typical towers of 138 kV transmission lines, from the application of modified Jordan formulas and Neumann integral equations are compared. According to results, for 138 kV transmission towers, the percentage differences are smaller than 1%, proving the accuracy of Jordan’s modified analytical formulas.