Comprehensive Fault Diagnosis Of Jointless Track Circuit Based On Simulated Annealing Algorithm

As the main technological equipment of railway transit enterprises, railway signal system is irreplaceable for ensuring the traffic safety, increasing the transportation efficiency and transmitting the traffic information. Jointless track circuit has already been widely applied in Chinese railway signal system. In this case, compensation capacitor and ballast resistor can be two important electrical parameters which play a critical part in ensuring the effective transmission of signals. When malfunctions and fluctuations are respectively occured on compensation capacitors and ballast resistors, the phenomena of “red-light-strap” and “code-missing” may appear to cause a negative effect in traffic safety and effective transportation. Thus, it is extremely necessary to generate the fault diagnosis on compensation capacitors and ballast resistors. This thesis took the resonance typed jointless track circuit as the research object and the shunt current data as the analysis object, the fault information of compensation capacitor and ballast resistor can be extracted to reach the fault diagnosis.Firstly, the shunt state model of jointless track circuit has been built. During the construction of this model, the recent study is to make the ballast resistor be equivalent to a uniform parameter. However, in reality, the ballast layer can be easily contaminated by sand, powder and budgust. And the trains' emergency brake will lead to the non-homogeneous of ballast. Thus, it is unrealistic to treat the ballast resistors as a homogeneous parameter. From what is mentioned above, this method implemented that through dividing the ballast section, the ballast value can be piecewise equaled with the boundary of compensation capacitor.Then, through mathematical modeling and analyzing the model with uniform transmission line theory and two port network, the transmission function of the shunt current amplitude envelope can be calculated. Through setting the basic electrical parameters and transmission functions, the shunt current amplitude envelope under the situations of ballast fluctuation and capacitor fault can be simulated to achieve the regulations among compensateion capacitor ballast resistor, and the current amplitude envelope.Finally, based on the regulations above, the complex fault diagnosis of jointless track circuit with the SA was raised. During this process, using compensation capacitor to divide the envelope line, the target function can be constructed by each section of the envelope line. Taking the compensation capacitor and ballast resistor as the decision variable, from the sending end to the receiving end,the SA was applied to all the target functions to obtain the optimum solution of the decision variable in order to achieve the minimum target function.During the solution, the results of each calculation will be saved and treated as the known variable for the next target function. When all the optimum solutions are calculated, the diagnosis can be finished.The method raised in this thesis can not only test the faults on multiple capacitors accurately, but also reflect the fluctuation situation of ballast resistors. Compared with the genetic algorithm, SA algorithm covered the advantages of high detection accuracy, low time consuming and strong practicability.