Influences of Damping Resistances on Transient Simulations in Transmission Lines

Abstract

Abstract-Simulations of electromagnetic transients in transmission lines can be carried out using simple circuit model. In the case of applications of simple circuit models based on π circuits, there are problems mainly caused by numeric oscillations. The lumped-parameter π equivalent model can be used with some advantages. The numeric integration method applied to the simulations of electromagnetic transients is the trapezoidal rule. If this numeric method is associated with the π equivalent model, results obtained from the simulations are distorted by Gibbs' oscillations or numeric ones. The introduction of damping resistance parallel to the series RL branch of the π equivalent model can mitigate Gibbs' oscillations in obtained results. Voltage peaks caused by these oscillations can also be decreased. So, in this paper, the combined influences of the introduction of damping resistance, the number of π circuits and the time step are investigated searching for minimizing Gibbs' oscillations and the voltage peaks in electromagnetic transient simulations. For this, transient simulations are exhaustively carried out for determining the highest voltage peaks, ranges of damping resistances and other parameters of the model, which minimize these voltage peaks caused by Gibbs' oscillations.

Application of Numeric Routine for Simulating Transients in Power Line Communication (PLC) Systems

“…The proposed modification initially involves adding damping resistors (R D ) in all π circuits [11,17]. These resistors are introduced in parallel with the elements in a series of the π circuits (elements representing the longitudinal parameters of transmission lines or waveguides) [28]. However, in spite of decreasing the effects of numerical oscillations considerably, the incorporation of damping resistances in each circuit of the cascade increases the computational time to perform the analyses and simulations of electromagnetic phenomena propagation.…”

“…In other cases, the different structures of π circuits, with and without damping resistance, are applied alternately in the composition of the cascade used to represent transmission lines or waveguides for analysis and simulations of transient electromagnetic phenomena propagation [29][30][31][32]. If the damping resistances are not applied in each π circuit of the cascade that represents the waveguides or the transmission lines, the numerical simulation can be numerically unstable [28][29][30][31][32]. The results of several simulations that will be used to compare and determine which structure is adequate to reduce Gibbs' oscillations without compromising the computational time will be presented.…”