A solution to transient failures of HVI track circuits caused by inrush interference based on wavelet analysis

A track circuit never reporting block failure means a track section is reported as vacant to a railway control system, even if it is occupied by a train. This is a wrong side failure which may cause an accident. A high-voltage impulse (HVI) track circuit based on the fast Fourier transform is currently in use in China to solve this problem, but it has been observed that when used in electric railway systems large inrush currents can lead to another track circuit failure mode, which is referred to as a transient reporting block (TRB) in this paper. The root causes and impact of TRB track circuit failures are analyzed and a solution to the TRB failure mode based on wavelet analysis is proposed. Computer simulations and onsite experiments are carried out and the results show that the proposed approach can accurately extract the feature frequency and then effectively avoid the TRB failure, even if the HVI track signal is disturbed by a significant inrush of traction-return current.