Analysis Of Transient Overvoltage Of Automatic Passing Phase Transient Process And Research On Inhibition Method

China’s electrified railway adopts a single-phase power frequency 27.5 k V AC power supply system.The three phases asymmetry of Traction power supply system’s topological structure is determined by the difference of electrical structure between High power single-phase load electric locomotive and Three-phase ac power supply.In order to solve the problem of the negative sequence of the traction network and the influence of the harmonics on the three-phase power system,the electrified railway adopts the scheme of commutating the power supply,and the traction power supply system is divided into turns.In order to solve the problem of the passive phase of the traction network,access to the three-phase power system,which formed the electric phase.The Neutral Sectioning Device for high-speed railway of our country adopts overlapping electrical sectioning device,but this kind of over-phase device in the actual engineering case will have some application problems,like Over-voltage,loss of locomotive speed,easy to have Electrical Arc,etc.Over-Voltage phenomenon is the main problem when the electric locomotive pass the Neutral Section,it will cause the roof of the insulation protection device was breakdown,arrester explosion and traction substation trip and other issues.Therefore,it is of great significance to study the electromagnetic transient process of locomotive over-electric phase separation to ensure the safe operation of locomotive and the normal operation of traction substation.In this paper,the principle of over-electric separation of electric locomotives,the method of over-phase and the research status at home and abroad are introduced and analyzed.Then the three types of automatic over-phase were compared.The traction electrical parameters related to the automatic over-phase of the electric locomotive are calculated,and the over-phase circuit model of the HX_D3 electric locomotive is switched by the ground switch and the simplified equivalent circuit model is established.At the same time,the transient process of HX_D3 star electric locomotive in the process of over-electric phase separation is calculated and analyzed,and the mechanism of over-voltage generation is analyzed and the actual working conditions is calculated.Then,according to the over-phase process of HX_D3 electric locomotive,the simulation model is built by Matlab/Simulink,the waveform of over-voltage of over-voltage of the locomotive is obtained,and the waveform is analyzed to verify whether it is related to the theoretical waveform Match.Finally,Various suppression over-voltage measures are discussed.This paper mainlydiscusses suppression over-voltage measures which is based on the RC absorber,and Show its superiority.RC absorber will be one of the main ways of transient over-voltage protection in the future of high-speed railway.