Electromagnetic Interference Caused By Arcs In Pantograph-Catenary Systems

In the modern electrical railway systems, a variety of electronic and electrical equipments are used. Computer communications and signal transmission become more common, and the electromagnetic environment becomes more complex. With the constant raise of the train's speed in the high-speed railway, the EMI problems caused by pantograph detachment have become a main problem in high-speed railway systems.This thesis focuses on the detachments of the contact between the over-head catenary systems and pantograph collector in the high-speed electrical railway systems. The simulation model of arc in the pantograph-catenary systems is established based on the actual pantograph-catenary systems, and analyzed the effect of the arc suppression device. Spectral characteristics of arcs are extracted through wavelet and FFT methods. Then, simulation and research work is done on the electromagnetic interference characteristics based on FEKO.The high frequency oscillation pulse caused by electric arcs when the detachments happened between the pantograph-catenary systems is the main source of electromagnetic interference noise in the electric railway. The results show that:The spectrum characteristics of arc in the pantograph-catenary systems range from 3MHz to 50MHz, in which the main frequency is 3MHz.The electromagnetic interference of arc in the pantograph-catenary systems has the most far-field gain along the direction of over-head catenary systems as well as the direction vertical over the interference sources. With different length of catenarys, different frequency of interference sources, and increasing number of interference sources, the electromagnetic interferences have been decayed to-25dB～-40dB at the concerned horizontal distance of 120 meters, and the vertical attenuation characteristics have also dropped to below OdB at the distance of 20 meters, which will not have a serious impact on the communication systems of the railway. At last, comparisons are done between the fitting curve of empirical formula and the simulated data to verify the correctness of the models and the simulations.