Research On Arc Model Of Articulated Phase Insulator And Laws Of Arc Motion Development In High Speed Railway

In electrified railways,there is a transition between the negotiated crossing and the nonnegotiated crossing while passing the articulated phase insulator.When the train transit from feeding section to another,multiple arcs may occur between pantograph and catenary.The arc is affected by multi-physically coupled field,which may further develop into wrong-phase short-circuit faults,ground short circuit faults,etc.which allows the arc exists for a long time,the catenary will be burned out and possibly leading to a serious accident eventually.The arc is much longer than which is generated by vibrations between pantograph and contact line.Therefore,research on arc model of passing articulated phase insulator and laws of arc motion development are of great significance to the identification of faults and setting of relay protection schemes.Based on the specific conditions of passing articulated phase insulator,this paper introduces the mechanism of arc generation and analyzes the types of faults that may further be caused by arc.Because of the difficult and risk to simulate the actual long arc,the numerical simulation technology is used in this paper.The arc is modeled from three aspects,the electrical characteristics of the arc and its laws of motion development are studied,and the type of faults that may further be caused by the arc is identified.Firstly,based on the classical arc black box model,the influence of parameters on electrical characteristics is discussed.Cassie and Mayr arc model are integrated into one model,parameters are determined for the specific conditions of passing articulated phase insulator,the wrong-phase short-circuit fault in cross coupling power supply system which caused by the arc is simulated in Simulink.By compare to the characteristics in a real wrong-phase shortcircuit fault verifies the correctness of the mathematical arc model.The black box model qualitatively expresses the voltage-current constraint relationship of arc.Under the premise of determining the fault type,it can provide the basis for the selection of the relay protection scheme,but it has limitations that cannot describe the morphological changes and motion development of long arc,and fail to identify the fault type caused by arc motion.Based on the theory of magneto hydrodynamics,this paper solves the twodimensional arc magnetic fluid model in Fluent,analyzed the influence of airflow,which provides some theoretical basis for the study of arc motion development.In order to study the different types of faults caused by arc motion,this paper draws on the idea of chain arc modeling,taking into account the electromagnetic force,wind load,thermal buoyancy and air resistance of the arc,and writing C language program in Matlab for simulation calculation.Simulated and analyzed the influence of different arcing phase and arcing position on the motion development,and judge the type of fault that the arc may cause under different conditions.