Research On Distribution And Suppression Measures Of The Reflux Safety Parameters Under The Insulation Damage Of Rail-ground

The emergence of urban rail transit has greatly alleviated the traffic pressure of large and medium-sized cities,however,with the long-term operation of urban rail transit system and geological conditions and other factors,the insulation performance of rail-ground has been greatly weakened,resulting in higher rail potential and stray current leakage problems more prominent,brings great safety hazards to the subway operation.Therefore,the simulation analyzes the static and dynamic distribution law of the rail potential and stray current as the return safety parameters under the conditions of ideal insulation and insulation damage,and finally puts forward the suppression measures,which is of positive significance to ensure the safe and reliable operation of the subway.This dissertation introduces the structure and characteristics of various parts of the DC traction reflux system,and expounds the corrosion mechanism of stray current in the reflux system,and summarizes the causes of the insulation damage of the railground.Based on the structure of the three-layer reflux system of "rail-draining network-earth",a network model of the resistance of the reflux safety parameters in the case of ideal insulation and insulation damage of rail-ground is established,and the important factors affecting the distribution of the reflux safety parameters are summarized through simulation analysis of these two static models.This dissertation analyzes the force of the train at different stages of operation,establishes the dynamic running equation,and simulates the train’s power-time and distance-time relationship curves.To study the static current calculation of DC traction power supply system at a certain moment,combined with the traction calculation model,to establish the dynamic current calculation model of power supply system,and to obtain the current distribution of each node of the power supply system under different operating conditions.Based on the resistance network model in the case of ideal insulation and insulation damage,the dynamic distribution model of reflux safety parameters is established by combining the dynamic current calculation model of the power supply system.By summarizing the operating status of single and double trains,the number and location of insulation damage points,the dynamic distribution law of reflux safety parameters in two cases is obtained.On the basis of summarizing the factors influencing the distribution of the safety parameters of the return flow,the measures to suppress the safety parameters of the return flow are optimized from the three aspects of source control method,drainage protection and zone protection.Aiming at the drainage device’s inability to intelligently control the drainage volume based on the on-site stray current leakage,a drainage volume prediction model based on the RBF neural network was established,and the feasibility of the model is verified and analyzed by the measured data.For the key sections of the line where insulation damage is likely to occur,high insulation protection can effectively reduce the rail potential and stray current,which is finally verified by simulation.The dissertation has 50 figures,15 tables,and 65 references.