Research On Generation Mechanism And Suppression Of The Pantograph Arcing Based On Ground’s Automatic Switched Neutral Section System

In the past few decades,China is fully committed to developing high speed railways and heavy haul railways.The urgency to solve the problem of passing neutral section which is brought about single phase power supply in railways has become increasingly prominent.With the use of ground’s automatic switched neutral section device,the pantograph detachment arc problem is highlighted and it has to be settled urgently when trains pass neutral section.Pantograph detachment arc hazards the safety of train travel.This dissertation carries out summarizing the research on generation mechanism and suppression methods of pantograph detachment arc.In this dissertation,the pantograph arc is investigated based on a thyristor-based neutral section system,which has been installed in Nanliang traction substation of Shenshuo railway.Mechanism of arcing production at sliding contact between pantograph and overhead contact wire is analyzed based on the infrastructure of overlapping section.Comparing and exploring the arc power of unit draft mode and multiple-operated locomotive units mode when trains pass through neutral section.Accordingly,arc suppression schemes are proposed and the arc suppression power-supply(ASPS)proposal is introduced.As far as the joint simulation model of the ASPS system and the traction power-supply system(TPSS)is concerned,the equivalent circuit model of the ASPS system based on the chain circuit of traction network is established.The simulation model verifies the current transition when the ASPS is put into use.The coupling of the four quadrant converter(4QC)and the TPSS will excite harmonic resonance.The three-phase voltage source PWM converter with an LCL input filter which is applied to the ASPS is researched on the basis of the harmonic current resonance phenomenon.The harmonic resonance phenomenon is occurred on the interaction system between trains and traction networks.In the dissertation,the advantages and disadvantages of the three-phase grid-connected converter with LCL filter are discussed.The mathematical model of the three-phase grid-connected converter with LCL filter is established.The control stability of the converter of the ASPS is analyzed.A dual-loop grid-current-feedback(GCF)control system and a dual-loop converter-current-feedback(CCF)control system is established.The system stability with GCF is higher than that with CCF.Two control schemes for the ASPS are discussed in the light of the equivalent circuit model of the ASPS system.The entire passing neutral section process is simulated and analyzed.The 3+0 modeling of train formation is as an example.Exploring the law of train current transfer when the ASPS is input actively.The principle simulation verifies the current transfer process on the power supply arm after the active input of the ASPS.The co-simulation system verified the function of the ASPS to suppress pantograph detachment arc.The traction network parameters was obtained accurately by ASPS.The loop impedance of arc suppressing was calculated accurately by means of output voltage and current test of the ASPS.Then,using the device installed in the field,the current transfer between the catenary and the neutral line when the ASPS was put into operation was tested.These theoretical proofs are eventually validated by experimental results.The ASPS has a certain inhibitory effect on the pantograph detachment arc.