Aprimoramento da estimativa de parâmetros que caracterizam linhas de transmissão aéreas.

Abstract

Accurate transmission line models must take the phenomenon of propagation of waves into account including the effects of the distributed nature and the frequency - dependence of the line parameters. In the available EMTP (Electromagnetic Transients Program) models, the line is completely represented by a propagation function A((o) and an impedance Zc(co) or admitance Yc(&). These parameters are approximated by rational functions so that a(i) and zc(t) or yc(t) are easily obtained. In this work, a brief review of transmission lines models is presented and some alternatives to approximate the parameters A(d)) and Zc(co) in a accurate and efficient way are proposed. It is shown that the used method is suitable to fit rational functions with real or complex poles and zeroes. Time domain simulations are carried out using data from the fitted functions in connection with a recently developed transmission line model proposed in the literature and not yet available in EMTP type programs.