Abstract:  The fault diagnosis of track circuit is very important for ensuring the normal operation and safety of trains. However, the existing researches on fault diagnosis of track circuit mostly focus on the hard faults diagnosis. And there is a lack of researches on the fault diagnosis methods of track circuit with tolerance. The existence of tolerance makes it difficult to apply related theory of fault diagnosis methods to actual engineering. Aiming at these problems, this paper researches the fault diagnosis of track circuit with tolerance and proposes methods to eliminate the effect of tolerance, based on sensitivity analysis. This paper also proposes the soft faults diagnosis dictionary methods of track circuit with tolerance, based on nodevoltage increments. The simulation experiment shows that the proposed methods can effectively diagnose the soft faults of track circuit with tolerance.

Key words:   track circuit; tolerance; soft fault diagnosis; nodevoltage increments relation function