Study Of On-line Method For Ballast Resistance Measurement In Jointless Track Circuit

As an important parameter of track circuit, ballast resistance plays a direct bearing on the quality of track circuit signal transmission and significantly affects the normal operation of track circuit, thus greatly influences the efficiency and safety of train operation. However, there is no excellent method for ballast resistance measurement of jointless track circuit prensently. Therefore, the research on method for ballast resistance measurement has a great practical significance and value. Based on the analysis of the influence of ballast resistance on amplitude envelop of induced voltage in cab signal (AEIVCS), an on-line method for ballast resistance measurement with train running data is proposed in the paper. The major work of this paper is as follows.1. Based on the transmission line theory, the model of AEIVCS is established. The influence of the factors such as compensation capacitor, the ballast resistance, the signal level of the transmitter, the shunt resistance and train speed on AEIVCS is systematically analyzed through the simulation of AEIVCS.2. L-M and SVM algorithm based qualitative analysis of ballast resistance is proposed. The cubic spline interpolation is adopted to eliminate the influence of train speed on AEIVCS. On the basis of influence analysis of ballast resistance, AEIVCS regression model is provided and verified. Then, the feature extraction method based on L-M algorithm for ballast resistance and the classification of ballast resistance based on SVM is proposed. Experimental results show that the qualitative method proposed in this chapter for ballast resistance analysis is effective for track circuits with the same carrier frequency.3. Based on the qualitative analysis method in the last chapter, the quantitative analysis method for ballast resistance in jointless track circuit is proposed. The relationship between parameters of equivalent model of AEIVCS and parameters of track circuit is reached through parameter identification of the equivalent model. Then, the mathematical model for fast estimation of ballast resistance is provided and the quantitative analysis of ballast reisistance is realized. Experimental results show that the method proposed in this chapter can makes a good eastamtion and performs correctly and effectively.4. Through the feasibility analysis of the application of the proposed on-line monitoring method in cab signal system, the overall design and scheme of the application is proposed. And functional design of on-line monitoring module is performed to implement the online estimation and remote monitoring function depending on the on-board recorder of cab signal. Experiments show that the online monitoring method for ballast resistance has a good performance on estimation. Finally, the modified method is proposed to adapt to the case with compensation capacitor fault and the applicability of the method proposed in the paper is improved greatly.