Study On Characteristics And Suppression Of Arcing Generated While Emus Passing Articulated Split-zone Insulator

With the development of high-speed railways(HSR),the constant increase of the catenary current carrying capacity and the fact that the main circuit breaker keeps closed as the electric multiple units(EMUs)passes the articulated split-zone insulator results that the pantograph arcing issue become increasingly prominent at the split-zone insulator.It not only affects the traction current collection quality of EMUs,but also cause the burnout of contact wire,which affect the safe and reliable operation of HSR.Therefore,fousing on solving the arc issue of passing split-zone insulator,this paper establishes the model of vehicle-grid power supply system regarding the dynamic arcing process of passing the split-zone insulator,and the electrical characteristics of the arc at the split-zone insulator is analyzed to propose the suppression scheme of arcing.Firstly,the generation mechanism of arc is analyzed.Actual location of split-zone insulator is considered to establish the simplified vehicle-grid circuit model.State space method is adopted to obtain the voltage difference between the two ends of split-zone insulator and analyze the arcing condition.By introducing Habedank arc model into the vehicle-grid circuit model,nonlinear state equation is deduced based on the circuit topology,and the discrete iteration is used to solve the state equation.The analytical results show that the voltage difference between the two ends of insulator meets the arcing condition and the excessive arc current amplitude is important factor of causing the excessive arc input energy.Secondly,combined with the actual mechanical structure of five-span articulated split-zone insulator,more accurate traction network lumped-parameter model regarding the split-zone insulator is established,and the CRH2-type EMUs is taken as example to establish the model of EMUs grounding system.Considering the dynamic arc trajectory of passing insulator,the black-box arc models that are applicable to the pantograph-catenary system of split-zone insulator are proposed,respectively,aimed at the transient processes of entering and leaving split-zone.On this basis,the simulation model of the vehicle-grid power supply system regarding the dynamic arcing process of passing split-zone insulator is constructed.The model validity is verified by comparing the simulation results with the measurement results.Combining the simulation analyses of arc behaviors at the insulator and the arc input energy calculation,the relation between arc characteristics and contact wire breakage is analyzed and revealed.Finally,considering the characteristics of excessive voltage amplitude and long current zero-crossing duration of split-zone arc,the suppression method of external protective equipment is studied and proposed.Considering the characteristics of long burning time and large input energy of split-zone arc,suppression method of improving the lifting height of contact wire between two central columns of split-zone insulator is studied and proposed.The state-space analytical method and the accurate model simulation are applied to verify the effectiveness of the above suppression methods.