Modeling And Simulation Of Shunt Current Under The Circumstances Of One Or Two Compensation Capacitors Failure

Track circuit is a circuit comprisedby the rail line and rail insulation.It is used to check the integrity of train and its occupation automatically and continuously.As an important component of track circuit equipment,The compensation capacitorcan effectively improve the transmission characteristics of the track circuit and extend its transmission distance.The compensation capacitor played an irreplaceable role in protecting the safe operation of trains transportation.Itsfailure will directly affect the transmission of the track circuit signal and the operation of the train control system and reducing the efficiency of the train operation.There would be only a little voltage drop of track circuit if only one compensation capacitor did not work,and this will not cause a "red track".Because of this,not like other obvious malfunction,the malfunction of compensation capacitor is not easy to find.Besides,if there is already a compensation capacitor failure,in the previous methods,we go to the railway to check he compensation capacitor one by one.It took a lot of time and labors.The fault diagnosis and maintenance methods like this surely cannot meet theneeds of the development of railway transport in China.According to a literature search,there is not much paper which take two compensation capacitors failure into account about the simulation of track circuit.Based onTransmission-line theory and Two-port network theory,the Track circuit is considered as acascade,which compose by a series of four-terminal networks.And the paper establish anequivalent Circuit model of the track circuit,the most important,this paper derived a mathematical expressionof theShunt current of ZPW-2000 track circuit under the circumstance of one or two compensation capacitors failure.And in this paper a friendly system of Shut Current Simulation base on MATLAB GUI was built which can simulateShunt Current curve of track circuit with one or two compensation capacitors failure.Since the phenomenon of electromagnetic between capacitorenvelope antennas and track circuit,the STM devices can detect induction voltage envelope of cab signal(IVECS),surely the IVECS has a Direct relationship with the Shunt current.The compensation capacitor' s good or not canaffect the shunt current curve and the IVECSdirectly.This study of shunt current Simulation also does a great help to the diagnosis and locationof compensation capacitor faulty.Based on the simulation results of the shunt current,it is obvious that the first compensation capacitoris the most important for improving the transmission function of track circuit.This can guide the maintenance work of the compensation capacitors.For example,the maintenance cycle of the first compensation capacitor should be shortened.At the end of this paper,Combined with the actual situation,the interference of induction voltage envelope of cab signal collected by the STM is analyzed and summarized.It explained the reason why there is difference between the real IVECS and the ideal one.At last,the effect of the compensation capacitor can be enhanced by a set of filter processing which is based on Moving Average Filtering,so that it can be easy to observe and analyze by the data reader.