Electromagnetic Interference in Modern Electrified Railway Systems with Emphasis on Pantograph Arcing

Sammanfattning: Electrified railways are undergoing rapid modernized in terms of increased speed, freight capacity and increased traffic. Traction systems are spread across countries with different signaling and power feeding systems. Signalling systems are undergoing modernization and now-a-days are more dependent on wireless and radio based services. Under these circumstances, there is a consistent demand on improved safety and operational reliability. Electromagnetic interference (EMI) and compatibility (EMC) issues play an important role in the overall performance on the traction power feeding and signaling systems. Some of them will be addressed in this thesis. 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 is more pronounced in the winter. Pantograph arcing is one of the main reason of broadband conducted and radiated EMI within the electrified railway systems. Experience within the railway industry has shown that this source of EMI and its characteristics need to be understood properly for a deeper understanding of the associated EMI issues. In this thesis the influence of various parameters like, speed of the train, load current, power factor etc. on this sliding arc and its consequences are shown. It is found that all these parameters control the arcing phenomena and also their corresponding signature patterns. It is shown that a net DC voltage and current component originates from pantograph arcing and causes interference in both traction power and signaling systems. Parameters that influence the net DC components are also discussed. Possibilities of radiated interference to the wireless and radio based communication and signaling are also discussed in brief.