Study on Pantograph Arcing and Investigation of its Influencing Parameters: Case Study-Addis Ababa Light Rail Transit

In electrified railways sliding contact between pantograph and overhead contact wire is one of the main modes of power feeding to the electrical drives and propulsion system within the railway. The traction supply could be either AC or DC at different voltage levels. Arcing from the pantograph is a commonly observed phenomenon and also the major source of Electromagnetic Interference (EMI) in the electrified railway system. This thesis presents the study of pantograph arcing and investigation of its influential parameters for the case of Addis Ababa Light rail transit (AA-LRT). The contact between the pantograph and the contact wire is the focus point for the design of an electrified railway system in order to keep the proper contact between them. The pantograph-overhead contact system is the system of electrified railway which is the place where pantograph arcing occurs due to the contact loss. The effects of contact distance, the weather condition, the vibration of the contact wire and the speed of the vehicle are simulated using MATLAB based on the mathematical modeling presented of this system and then analyzed for the case of AA-LRT. As the result, the weather condition and the speed of the vehicle has no any effect on the occurrence of arcing. In the case of contact distance, pantograph arcing occurs if the separation of the pantograph is not greater than 0.25mm. However, the effect of vibration of the contact wire has been found a serious cause for pantograph arcing. The pattern of the vibration is simulated for different span length (20m, 30m, 50m) and the weight of the catenary. In order to avoid the contact loss produced by the vibration of the contact wire, the minimum distance between two consecutive pantographs shall be 167 meters. Finally, it has been recommended that the railway company running the AA-LRT will not send its vehicles uncoupled so as to avoid the effect of the front pantograph onto the next pantograph.