Study On Multi-parameter Online Monitoring System Of Pantograph-catenary Arc

High speed railway has been widely used all over the world because of its advantages of fast speed,small pollution and large carrying capacity.The pantograph is the key component of the high speed train to obtain the electric energy from the catenary.The good dynamic contact performance between the pantograph and the catenary is the basic guarantee for the safe operation of the train.As the speed of the train increases,the vibration between the pantograph and the catenary intensifies,resulting frequent off-line and arcing of the pantograph catenary.Arc plasma has the characteristics of high temperature and high energy,it will not only ablate the catenary and the pantograph strip,but also produce high frequency electromagnetic noise and overvoltage,which threatens the safety of train operation.At present,the detection of pantograph-catenary arc mainly focuses on video image detection and ultraviolet parameter detection,and some achievements have been achieved,which lays a good engineering foundation for on-line monitoring of pantograph-catenary arc in high-speed railway.However,it is difficult to fully reflect pantograph-catenary arc information by a single measurement parameter.Therefore,it is of great practical significance to develop a set of on-line monitoring devices which can obtain multiple parameters of arcing arc at the same time.The arcs produced by the pantograph off line are mainly radiated by electrical,acoustic,and optical signals.Optical signals include arc plasma optical radiation(including ultraviolet and visible light)and infrared radiation signals of molten pool.The acoustic signal is mainly a plasma sound signal.The electric signal mainly refers to the voltage and current signal of the arc.All of the above signals contain varying degrees of arc information,The average excitation temperature of arc plasma can be calculated by detecting the emission spectrum information of arc plasma;The ultraviolet information of the arc can reflect the discharge amount of the arc;The arc power can be calculated from the voltage and current information of the arc;And the intensity of arc and the ablation of pantograph strip can be qualitatively reflected by analyzing the spectrum information of arc acoustic signal.Based on the optical,acoustic and electrical signals produced by arcing arc,this paper develops a set of online monitoring system for multi-parameter arcing arc by selecting suitable sensors.The system is mainly composed of hardware and software.The hardware part adopts a high-speed multi-channel synchronous data acquisition scheme which combines the technology of FPGA and USB2.0.Based on this scheme,the corresponding functional circuit module is designed.The software part mainly includes the control program of the FPGA and the monitoring program of the host computer.On the basis of the design of the control program of the FPGA,the timing simulation of the main functional modules is carried out to verify the effectiveness of the timing design of the high-speed multi-channel synchronous data acquisition.Through the monitoring program written in C# language,the functions of real-time receiving,processing,displaying and storing multi-parameters of pantograph-catenary arc are realized,which is convenient for staff to collect and analyze arc data.Finally,the pantograph-catenary arc generator verifies that the system can effectively monitor the pantograph-catenary arc plasma excitation temperature,arc power,ultraviolet pulse number and arc acoustic signal,and the influence of different current and pantograph-catenary gap distance on the pantograph-catenary arc parameters characteristics is explored.