Cálculo de tensão induzida por descarga atmosférica: : implementação da teoria de Rusck no EMTP

Abstract

This work deals with the implementation of the Rusck's theory of the lightning induced voltage on distribution lines in the Electromagnetic Transients Program - EMTP. The EMTP is one of the most powerful and used computer programs for electromagnetic transient's simulation in power systems. The transmission line models implemented in this program used for studies of electromagnetic transients in power systems are not adequate to analyze directly voltages. The Rusck's theory developed by Sune Rusck in 1957 was used to evaluate the induced voltage effects. Although others have been developed to simulate lightning induced voltages on lines and equipment, the Rusck's theory, with in the approximations originally conceived, predict the same results compared with others theories and UFMG team has been used extensively. According to this theory, it is possible to obtain an analytical expression describing the lightning induced vooltage at a point of an infinite homogeneous line. Finite lines with simple discontinuities can be considered if the theory is slightly modified. Then, to implemented this theory is necessary to dicretize the line un segments and to put current sources along the transmission line. The results obtained are compared with a phase-neutral electrical line, reduced scale model and measurements on an experimental distribution line during nearby rocket triggered lightning flashes to validate the results obtained with EMTP-RUSCK methodology. The present research developed a new engineering tool to study induced overvoltages caused by lightning discharge nearby, coupling with the EMTP.