Emu-traction Network Modeling And Study On Electromagnetic Transient Of High-speed Railway Considering The Detachment Arcing Under Multiple Conditions

The good contact between the pantograph and the catenary on the high-speed railway(HSR)is the key to maintain the reliable flow of the high-speed train.With the railway developing more rapldly,more conveniently,more efficiently and more securely,some problems have been exposed in the operation of electric multiple unit(EMU).For example,detachment arc on pantograph-catenary system occurs during EMU running process.As EMU passes articulated electrical split-phase,arcing phenomenon also exists for the continuous contact separation between the pantograph and the contact line.The detachment arc will not only burn the pantograph and contact line,but also cause transient overvoltage,which threatens the safely operation of the traction power supply system of HSR.Firstly,aming at the electromagnetic transient phenomenon caused by the pantograph detachment arcing,during normal operation and passing split-phase conditions of the EMUs,the internal mechanism of pantograph off-line overvoltage is analyzed based on theory in this paper.Then,the state space analysis method is used to study the electromagnetic transient effects of the two conditions.In addition,the modeling process of the distribution parameters of the traction network,the establishment of the nonlinear state equation and the discrete solution algorithm of the equation are given in detail.The theoretical results show that multiple arcing is one of the important factors that cause the voltage distortion and transient overvoltage of the traction network.Then,in order to combine theory with simulation,and more accurately reflect the influence of electromagnetic transient,a more accurate EMU-traction network model for AT full-parallel power supply mode is established based on the theory of multi-conductor transmission line(MTL)in this paper.A chain model of traction network is set up through deducing the parameters of the MTL chain lumped ? network matrix of traction network at first.After that,a EMU model considering grounding return loop is established according to the structure parameters of CRH2.On this basis,combining the model of EMU and traction network,the 142.5m EMU-traction network chain parameter model,and the 125 m EMU-traction network of passing split-phase region chain model are set up respectively,considering the relative location and relation of electrical parameters of vehicle,rail and traction networks.Finally,a traction network-EMU model,which reflects the complete loop of traction network,is established.It is multi-angled,more comprehensive,multi-operating,and more closely related to the reality,and can be used to simulate and analyze the influence of detachment arc.In view of the above two conditions,the electromagnetic transient phenomena of first detachment arc and multiple detachment arcs from the perspective of one EMU and multi EMUs operation in the traction network is simulated,the influence to EMUs and traction network is analyzed.The simulation results are consistent with the theoretical analysis results,and the simulation model can also be used for other problems in traction power supply systems.