Study On Overvoltage Of Rail When The Electric Locomotive Passes Through The Neutral Zone

In recent years,with the continuous development of High-speed,Heavy-Haul and electrification of China’s railway,an increasing number of faults caused by traction current interference appear in railway equipment,which seriously affect the train operation efficiency and even causes harm to personal safety.Many faults are caused by the overvoltage when the train passes through the neutral zone.Therefore,it is of great significance to clarify the generation mechanism of overvoltage when the electric locomotive passes through the neutral zone,to understand the transmission path of overvoltage and to put forward effective solutions.The main work of this paper is as follows:Firstly,different ways of electric locomotive passing through the neutral zone were introduced.Then the advantages and disadvantages of three automatic ways were compared,and the electric process of electric locomotive passing through the neutral zone was analyzed.The cause of the overvoltage between the contact line and rail was finally determined.Secondly,based on Multisim,a complete simulation model of electric locomotive passing through the neutral zone including traction substation,catenary,neutral line,electric locomotive and rail impedance was established.During the simulation process,due to the mutual influence and restriction of over-voltage frequency and the impedance from electric locomotive to traction substation,the genetic algorithm and dichotomy are used to calculate the over-voltage frequency and the impedance from electric locomotive to traction substation,so as to simulate the over-voltage waveform at the contact line and rail.It was found that the amplitude and frequency of overvoltage are related to the time of lectric locomotive passing through the neutral zone,equivalent capacitance and inductance of electric locomotive and leakage conductance of rail.Then,using the simulation model,the method using RC circuit to suppress overvoltage was studied.Through simulation,the ideal RC parameters were determined.Finally,the relevant test points are set up and the on-site test was carried out in the fault section including the neutral zone.Analyze and compare the collected field data,each scene of the electric locomotive passing through the neutral zone are inferred,and the generation mechanism of the over-voltage is clarified.The simulation results were compared with the measured data to verify the correctness of the simulation model.The paper includes 42 pictures,12 tables and 62 references.