Compensation capacitor fault detection method in jointless track circuit based on Levenberg-Marquardt algorithm and generalized S-transform
基于Levenberg-Marquardt算法和广义S–变换的无绝缘轨道电路补偿电容的故障检测

Transmission-line theory is used to study the impact on the short circuit current in the jointless railway track circuit caused by the faulty compensation capacitor. Levenberg-Marquardt(L-M) algorithm is used to verify the validity and adaptability of the regression model for the short circuit current. According to the operation principle of the cab signal, the envelop of the induced voltage recorded in cab signal represents the short circuit current; its attenuation tendency is removed through piecewise exponential fitting based on L-M algorithm. Secondly, Generalized S-transform(GST) is used to compute the instantaneous frequency. Finally, based on the instantaneous frequency, location of the faulty capacitor is determined. Experiment shows that due to the high time-frequency resolution of GST, the faulty capacitor is accurately located. Because the data used are drawn from the cab signal, this method shortens the detection interval, reacts more promptly and with lower cost and less impact on railway transportation than other current methods.