LAUSR

Abstract This paper presents a new approach for detecting the natural frequency of transmission power lines applying S-transform on Transient Recovery Voltage (TRV). TRV usually appears between terminals of a circuit breaker during an isolation of a fault. The TRV phenomenon contains wideband frequency information such as the natural frequency of the system that depends not only on the electrical transmission line characteristics but also on the location of the fault. S-transform was applied to the TRV signal and the energy content in the time-frequency contours was evaluated using Parseval's theorem. This analysis ensures the accurate identification of the natural frequency of the resulting system by locating the maximum relative of the energy content. The case studies studied involved taking actual systems and using frequency-dependent phase models. The experiments were performed to show that the proposed approach can robustly determine the frequency associated with the parameters of the line. Different cases were considered: distances, inception angles, fault resistances, circuit breakers and models of electric arc. The simulation results demonstrate that using S-transform to analyse TRV provides a simple and reliable method for determining the natural frequency and opens a new way for studying the behaviour of protections and faults in power systems.