Electric arc power collection for high-speed trains

One of the many problems in high-speed ground transportation is supplying the necessary power to the vehicle, as on-board power generation is not attractive due to the rapid increase in the power requirement with speed. Power collection with a sliding pantograph becomes increasingly difficult as train speed increases. Alternative methods of contactless power collection are critically reviewed in this paper. It is concluded that power collection along the line using an electric arc appears to have the best advantages. A study of the literature has shown that arcs can be driven magnetically at speeds higher than 500 km/h without being extinguished, and that electrode wear at high arc speed is relatively low. The known problems of arc initiation and reignition at high speeds are not insurmountable in the light of present day experience and techniques in this area. The results of an experimental investigation of power collection by an electric arc which is being carried out at the University of Sheffield are also included. The electrode geometry plays a significant role in the arc maintenance, and interelectrode gap changes from 1 to 10 cm can be tolerated without reduction in arc lifetimes under certain conditions. Experimental results on electrode wear which is affected by arc current level, arc speed, and the electrode material, are presented. These show that the damage to the overhead wire is at an acceptably small level.