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Frequency Characteristics and Transient Response of Transmission Lines with Longitudinally Varying Ambient Temperature

Mohamed Mostafa Saied


This paper addresses the steady state, the frequency characteristics and the transient response of
power lines in the presence of longitudinally varying ambient temperature. This variation will
lead to location-dependent line circuit parameters and to a changing equivalent circuit. The
derived models, which are based on the exact long line theory, can incorporate the impact of the
different patterns of the temperature distribution in terms of location and magnitude. Several
case studies of the resulting non-uniform lines are investigated. The results include the steadystate
response at any frequency, the transient voltage and current distributions and the line’s
input impedance under various loading conditions.
Keywords: Ambient temperature, distributed parameter circuits, frequency characteristics, line
modeling, non-uniform lines, power transmission lines, steady state, transients

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