Research And Application On Pantograph Arc Detection System Of Urban Rail Based On Solar-blind Region

Pantograph arc is one of the main factors that affect the relationship of pantograph-catenary system.The Pantograph-catenary parameter detection system can detect pantograph arc phenomenon and provide data support for maintenance work and improvement of pantograph relationship in long-term operation in the future.However,due to the differences in power supply system,train operation mode and pantograph structure,the mature pantograph arc detection system applied in AC electrified railway is not fully applicable to the detection of pantograph arc in urban rail transit.Considering the differences in the geographical,climatic and illumination conditions of urban rail transit,it cannot be generalized.Based on this,this dissertation takes Lanzhou Rail Transit as an example to develop a pantograph arc detection system,which is suitable for urban rail power supply system and illumination conditions,based on the solar-blind ultraviolet signal as the characteristic band.In this dissertation,the key technologies of the pantograph arc detection system for urban rail transit based on the solar-blind region are solved,such as the determination of characteristic optical band,the design of arc light acquisition system,the conversion of optical signal to electric signal,and the determination of the type of output electric signal of the detection system based on the solar-blind area.The specific work is as follows.The range of characteristic band collected by the pantograph arc detection system is determined.The selection of characteristic band of light signal is related to the accuracy of pantograph arc intensity judgment,and also affects the selection of lens optical component parameters of arc acquisition system.The characteristic bands should distributs in the solarblind region,and avoiding the tunnel light spectrum.The distribution of arc intensity is relatively concentrated in the range of characteristic bands and can linearly reflect the variation of arc intensity.On the one hand,the characteristic band depends on the solar-blind area of the solar and the tunnel light spctrum of Lanzhou,on the other hand,it depends on the pantograph arc spectrum.Therefore,three spectral experiments are implemented,which are the solar spectrum experiment,tunnel light spectrum experiment and urban rail pantograph arc experiment.Based on the comparison and analysis of the experimental spectral data,the characteristic optical band of the arc detection system developed in this dissertation is determined as 275?285 nm.The lens parameters of the arc acquisition system are calculated and designed in detail.The optical signal of 275?285 nm is projected onto the optical fiber at the end of the lens after passing through the arc acquisition system.In order to minimize the loss of arc signal in the coupling process between the lens and the fiber,the imaging size of the object plane where the arc is located on the image plane of the optical system should be smaller than the optical fiber end face,the size of image point and aberration parameters should be as small as possible.In this dissertation,ZEMAX optical design software is used to design of optical lens parameters.According to the position of roof equipment of Type A vehicle used in Lanzhou rail transit,the optical lens parameters design under 3 m,5 m and 10 m object distance schemes is given.Finally,the image size,image point size and aberration parameters of each design scheme all meet the design requirements.The photoelectric conversion module is designed and the type of electrical signal output is determined.R9880U-210 PMT(Photomultiplier Tube)is selected as the photoelectric conversion component.This type of PMT is sensitive to optical signals in the 275?285 nm band,and can convert the optical signals irradiated to the PMT cathode into electrical signals in a certain proportion.According to the principle of photoelectric effect,the feasibility of using PMT output current value and voltage integral value as detecting signals to reflect the pantograph arc is deduced and analyzed.A photon counter is designed which is used to count the number of photons received by PMT cathode and prove that the detection system can linearly reflect the pantograph arc intensity.In order to verify the effectiveness of the scheme,the pantograph arc detection system was applied to the No.13 train of Lanzhou rail transit line 1,and several online pantograph arc detection tests were carried out.During the tests,different test conditions were set considering the factors that may affect the results,such as line conditions(above ground and underground),natural light(day and night),train load(no load,full load),train running speed,train running state(acceleration,uniform speed,braking),etc.The test results show that the system can detect the phenomenon of arc without the influence of external factors,and the detection rate reaches 98.41%.The nonlinear error is 4.12% when the voltage integral value of the photoelectric conversion module is used to measure the arc strength of the pantograph,while the nonlinear error is 12.84% when the current value is used.Therefore,the arc burning detection system mainly uses voltage signal as the detection parameter,and current signal as the auxiliary reference.The pantograph arc detection system runs well in Lanzhou rail transit Line 1,and the detected pantograph arc data provide certain data support for the repair and maintenance of the pantograph system.