Online Monitoring Of Catenary Based On Current Distribution

With the large-scale construction and operation of high-speed railway,the transportation task of railway system has been greatly increased,which makes the safe and reliable operation of traction power supply system an important problem affecting the railway development.The data on the railway operating failure of at home and abroad show that catenary fault accounted for a large proportion in the traction power supply system failure.However,the catenary is erected by the open air and has no spare,that its failure will directly affect the normal operation of traction power supply system,and it will interrupts parking,affect the normal railway transport when the accident is serious.Therefore,research on the reliability of catenary system is very important to improve the reliability of traction power supply system.In this thesis,firstly,study the static current distribution and dynamic current distribution with the change of flow point position,analysis the distribution characteristics of percent current.Then,on this basis,an evaluation method is proposed,which using the percentage change of reference wire current to monitor the status of wire breakage of catenary wire,that complete online monitoring of the catenary wire disconnection fault.The main contents of this paper are as follows:Firstly,the model of direct power supply section and AT power supply section of Beijing-Shanghai high-speed railway was established,verifying the rationality of the model though studying the current distribution of each branch of the model under the normal operating conditions.Then depending on the catenary simulation of dynamic simulation to analysis of the current distribution changes,we put forward a method that use a current sensor to measure the reference current value in percentage form to monitor the nearby catenary wire hanging string fault.Based on the catenary model of different power supply mode,we study the law of the current variation in the case of disconnection faults of different suspension strings,and get the current curve under different fault conditions.Compared with the current curve under normal condition,we analysis the current variation,verify the method's rationality,achieve the goal which test the on-line monitoring theory of broken wire fault.In order to achieve the visual judgment of the catenary's status,the data processing process based on the algorithm flow chart is proposed,use the arithmetic operation method to process the measurement data.By optimizing the arithmetic method,proportional-squared difference summation method and Half Cycle Direction Method are put forward.It provides a diagnostic strategy for the direct power supply and AT power supply of the contact wire disconnection fault,offers a reasonable judgment basis and data guarantee for the on-line monitoring system of the broken strings of the hanging strings,indicates the direction of catenary on-line monitoring technology.