| By far,the pantograph-catenary offline discharge has become one of the main disturbance sources leading to EMC problems of high-speed railway signal system.The electromagnetic noise spectrum generated by pantograph-catenary offline discharge can cover the working frequency bands of almost all on-board equipment.These years,the rapid development of satellite navigation and positioning technology has been widely concerned about because of its real-time,high-precision,all-weather and many other characteristics.In view of the advantages of satellite navigation technology compared with the existing train’s positioning technology,the application prospect of satellite navigation technology in the railway field is bound to be broader with the development of the on-board satellite navigation technology.The satellite navigation receiving antenna represented by GPS antenna is the sensitive equipment to be studied in this thesis.The frequency spectrum of pantograph-catenary offline discharge noise can cover its working frequency band and result in electromagnetic interference.However,due to the fact that satellite navigation technology has not become the mainstream railway positioning technology in the world,the research on the interference of pantograph-catenary offline arc to its antenna is not rich,which fully illustrates the novelty of this topic.Firstly,this thesis simulates the Mayr arc model by MATLAB.Then,the railway power supply system is simplified based on Mayr arc model,and the pantograph-catenary offline discharge model is built and simulated.The simulation results show that the pantograph-catenary offline discharge will produce high-frequency electromagnetic interference,but it is far from reaching the working frequency band of GPS antenna.Then,a high-frequency and high-current acquisition device is invented to collect the offline discharge current signal of the simulated pantograph-catenary system,and the parameters of a mathematical model of pantograph-catenary offline signal are selected quantitatively by using the time domain and frequency domain characteristics of the signal.The GPS antenna model,simulated pantograph-catenary system model and real size pantographcatenary system model are established on the platform of the East Wave electromagnetic simulation software,and the mathematical model of pantograph-catenary offline signal is used as excitation source for simulation to explore the variation characteristics of interference current received by antenna port with distance and catenary’s length.Finally,the radiated noise of simulated pantograph-catenary offline discharge signal and pantograph-catenary offline discharge signal are tested.The amplitude of pantograph catenary off-line discharge is very low near the working frequency band of satellite navigation receiving antenna,so it is hard to produce an obvious effect on it.The main innovations of this thesis are as follows:1.In this thesis,the influence of pantograph-catenary offline signal on satellite navigation receiving antenna is studied from three aspects,which are computer simulation,laboratory test and field test.2.In this thesis,the parameters of a mathematical model of pantograph-catenary offline signal are selected quantitatively according to the engineering practice.3.In this thesis,a simulated pantograph-catenary system which can simulate the pantograph-catenary offline discharge under different working conditions but the same phase is built.This thesis innovatively presents a device for collecting discharge signal of the simulated pantograph-catenary system based on the principle of capacitive induction,and uses a wide-band antenna to collect the radiation signal of the simulated pantographcatenary system discharge under different conditions.The above-mentioned research content is significant and valuable for further research and engineering application. |
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