Research Of Inrush Current Elimination System Of The Electric Locomotive

When the electric locomotive changes phase in the overphase area,there will be a short time breaking process.Until the locomotive is reelectric,the transient process may occur due to the sudden increase of the voltage of the main transformer,thus causing the distortion of the voltage and current of the transformer,overvoltage and inrush current,and then lead to the discharge of the vehicle lightning arrester.The contact fault of the overhead contact line and the malfunction of traction transformer protection seriously affect the safe and stable operation of electric locomotives.Therefore,there is of great practical significance to study the transient process of electric locomotives and the related inrush current suppression techniques to provide a theoretical basis for solving practical problems.By analyzing the characteristics of the electrified railway traction system,the transient process of the locomotive over phase area is analyzed and studied.The operation process and transient range of the locomotive under the two modes of the vehicular and ground switching locomotives are paid more attention to theoretical analysis and study.Two kinds of electric locomotive excitation inrush current suppression techniques are proposed for locomotive traction transformers,traction substations and other locomotives caused by the transient process produced by the overphase of the locomotive.A static switching control technique for suppressing inrush current of electric locomotive is proposed.Power electronic technology is used to control the voltage on the primary winding side of the locomotive transformer by controlling the timing of the static switch.When the magnetic flux of the transformer core is near the zero point and the zero point,the switch can be open or closed.Besides,a method for judging the switching range of a static switch is proposed which can determine the switching range of the static switch.When the static switch is switched on in the range,the main transformer of the locomotive will not generate excitation inrush current.Using the proposed method,the simulation model of electric locomotive transformer for passing neutral section is established,and the simulation results show that when the electric locomotive is in excessive phase,there is no excitation inrush current,and this system can effectively inhibit the switching inrush current generation,and verify the effectiveness of this method.A new principle of electric locomotive inrush current elimination system is proposed which is based on high power electronic technology,meanwhile presents two kinds of PWM modulation voltage algorithm,respectively which are cophase amplitude modulation and frequency conversion phase shift.By controlling the new high power electronic circuit rectifier,inverter,frequency conversion mode and locomotive transformer excitation voltage at different times to achieve electric locomotive non-inrush passing neutral section,and to remove the inrush current when the transformers are switched on.Using the proposed method,the simulation model of electric locomotive transformer for passing neutral section is established,and the simulation results show that two kinds of voltage modulation algorithm can effectively inhibit the switching inrush current generation,and verify the effectiveness of this method.This chapter carries out theoretical and Simulation Analysis on the power supply mode of double-system locomotive,and aims at two kinds of power supply modes of double flow system.In the transient process,a suppression technique to suppress the inrush current is proposed to suppress the switching of the dual flow power supply mode.By rectifying the inverter,a gentle voltage is applied to the neutral line,and the locomotive will not produce exciting inrush during the commutation process.Finally,the feasibility of the method is verified through simulation.