Dynamic Calculation Of Ballast Resistance Based On Transmission Theory Of Track Circuit

Track circuit is the key part of signal transmission and train occupancy detection,which plays an important role in the stability of train control system.ZPW-2000 A track circuit has the advantages of safety,reliability and stability,which is widely used in China’s railway lines.As the main factor that affects the stability of track circuit,the resistance of track bed is easy to be affected by many factors such as material and environment,so it shows the characteristics of dynamic change.If the resistance of track bed is too low,the track circuit will not work normally,which will affect the efficiency of railway transportation and even cause safety accidents.The existing measurement methods can not meet the dynamic calculation of ballast resistance,so it is of great significance to study the dynamic calculation method for ballast resistance of ZPW-2000 A track circuit.Based on the transmission theory of track circuit and the method of mixed programming of MATLAB and QT software,a simulation calculation system of ballast resistance is designed in this paper.The main research of this paper is as follows:(1)Based on the research on the composition and working principle of ZPW-2000 A track circuit system,according to the basic principle and structure of each equipment in the transmission channel,combined with the theory of two port network and uniform transmission line,the transmission model and parameter selection method of each equipment in the system are established.Through the actual parameter measurement,the track circuit system simulation is established,and the accuracy of the simulation method is verified by comparing the actual test data,and the influence law of the ballast resistance on the track circuit is analyzed comprehensively.(2)The rail surface current data set is obtained by measuring the rail surface current several times with the rail surface current measuring device.The outliers are eliminated by K-means clustering and lof algorithm,and the average value of the rest data is calculated to get the accurate current measurement value of each point on the rail surface.According to the test data,this method can eliminate the outliers in the data set accurately.On the basis of accurate simulation model,according to the corresponding relationship between rail surface current and ballast resistance,the model parameters that need to be optimized are determined by analyzing the influence of SVM algorithm model parameters on regression accuracy.PSO algorithm is used to automatically optimize the parameters in SVM.The best combination of parameters is input into SVM model,PSO-SVM model is established,and the actual ballast resistance value is obtained by regression fitting.The results of regression prediction of test samples show that the method can accurately calculate the resistance of ballast bed.(3)Based on the simulation and regression calculation of track bed resistance,combined with the advantages of QT creator and MATLAB,a track bed resistance simulation calculation system for non insulated track circuit is developed by using the mixed programming method.The test results show that the system can realize the simulation calculation of track bed resistance.Finally,the system is encapsulated as an executable file to realize the portability of the system.