Analyses of the Spurious Oscillations in the Lumped Parameters Line Model

The currents and voltages in the multiphase transmission line are described by differential equations that sometimes can be difficult to solve due the mutual coupling and skin effect that have to be considered for accurate results. An alternative consists in using a matrix to decompose the multiphase transmission line in n single-phase systems uncoupled. For evaluating modal voltages and currents, each system will be represented by two models well-known for studies in electromagnetic transients in transmission line. The first model uses the lumped parameters to represent the transmission line and it is developed directly in the time domain. The second model uses the distributed parameters and transforms the differential equations in the time domain to algebraic equations in the frequency domain using Laplace Transform. Once solved them, it can be applied the inverse transformation and the solutions are obtained in the time domain. It can be observed the presence of spurious oscillations in the lumped model simulations. This work will analyze the spurious oscillations in the voltages in the open receiving end using, considering a fixed-length transmission line, represented by different quantities of pi-circuits during energization process.