26-01-2012, 04:00 PM
Overvoltage protection concept for DC railway systems
ABSTRACT
Overvoltages in electrical networks result from the effects of lightning strokes and switching actions and cannot be avoided. Furthermore, the power supply of electrical railways is endangered by direct or nearby lightning. A new device, combining protection against overvoltages and touch voltages and protection of people is introduced. Protection concepts for DC railway systems are introduced, considering the different insulation of the rails and the earthing concepts. The requirements and ratings for gapless MO-surge arresters (or short: arresters) are based on the relevant EN standards and national guidelines. A newly developed hybrid voltage limiter, which combines overvoltage protection and the protection against dangerous touch voltages, is introduced. Overvoltages in electrical supply networks result from the effects of lightning strokes and switching actions and cannot be avoided. Furthermore, the power supply of electrical railways is endangered by direct or nearby lightning.
