Abstract
This paper investigates lightning surge overvoltages on a coil system of a magnetic-levitation train, when lightning hits an overhead ground wire(GW) to protect the coils. The paper considers an elevated railroad with height of about 20 m from the earth surface and iron structures which were neglected in the previous investigations. The overvoltage induced to the coil due to the lightning current on the GW increases by about 30% when considering the grounding lead of the GW. The iron structures reduce the lightning overvoltages by about 10% when the structure is assumed to be directly grounded to the earth. If the grounding lead of the structure is taken into account, the reduction effect is not much noticeable. The induced overvoltage to the coil enters into a power feeding cable, and produces an overvoltage which may exceed the cable sheath insulation level. The overvoltage can be controlled by an arrester.
