Spectrum analysis of transient responses of overhead transmission lines

Accurate modelling of transients in overhead transmission lines requires the use of proper time domain or frequency domain models. The derivation of an optimal frequency for the calculation of line parameters is very significant in time domain modelling. The methodology followed in this paper begins with the analysis of the spectrum of transient responses, in order to calculate the dominant transient response frequency. A thorough investigation on line length, terminations and the type of transient investigates certain empirical rules and clarifies the influence of these factors on transient responses. Results obtained in the time domain, using the proposed dominant frequency, are validated by the corresponding obtained from a frequency domain model. Using a similar procedure in multipath propagation topologies, the influence of the input surge impedance on the dominant transient frequency is investigated, leading to significant remarks.