Study On On-Line Estimation Method Of Compensation Capacitor In Jointless Track Circuit

As one of the key subsystems of the train operation control system,the main function of the jointless track circuit is to realize the train occupation and integrity inspection,and cooperate with the track circuit reader to complete the information transmission between the train and the ground.In order to equalize the high inductive reactance characteristics of frequency shifted track circuit signal transmission in rail line,the way of equal interval parallel compensation capacitor on track line is usually adopted.The compensation capacitor has the characteristics of large quantity,wide distribution and high failure rate.The decrease of capacitance and disconnection are the main failure forms,and the result will affect the railway traffic safety and transportation efficiency.In order to meet the development needs of "condition based maintenance" of compensation capacitance and make up for the shortcomings of existing fault maintenance and planned maintenance,this paper proposes a capacitance estimation algorithm of compensation capacitance of jointless track circuit based on the actual data of remote monitoring.The main research work is as follows:1.The feasibility of realizing the estimation of compensation capacitance based on the remote monitoring data of locomotive signal is analyzed.Based on the transmission line theory,the transmission process of locomotive signal remote monitoring data is modeled and the influencing factors are analyzed.The feasibility of estimating the compensation capacitance based on remote monitoring data is analyzed from the data source level,model matching level and influence law level.2.An estimation method of compensation capacitance based on remote monitoring data of locomotive signal is proposed.Firstly,the remote monitoring data are denoised based on empirical mode decomposition,normalized and interpolated based on cubic spline method.Secondly,a method based on linear fitting is proposed to estimate the envelope of broken line.Then,based on the transmission line theory,the short-circuit current amplitude ratio at the left and right half of the compensation unit length of the compensation capacitor and the short-circuit current amplitude ratio at the compensation capacitor and the length of a compensation unit at the receiving side are deduced respectively.On this basis,a fitting normal envelope based on quadratic function is proposed.Finally,according to the correlation between the ratio of the area between the fault envelope and the broken envelope and the area between the normal envelope and the broken envelope and the capacitance of the compensation capacitance,a capacitance estimation function is constructed,and the capacitance of the compensation capacitance is calculated based on this function.3.Based on the actual data and simulation data,the function and performance of the compensation capacitance estimation algorithm are verified,and the influence of the main parameters of JTC on the capacitance estimation algorithm is analyzed respectively.Experiments show that the proposed method has high accuracy,fast detection speed and strong robustness,and the change of ballast resistance and shunt resistance has no obvious impact on the algorithm.4.Based on the locomotive signal remote monitoring platform and QT programming language,the software of compensation capacitance estimation system for jointless track circuit is designed and implemented.According to the field application requirements,the interface design and function design of the software are carried out,and the functional modules are verified.