AC Electrified Rail Train Converter Switching Overvoltage Transients Study

In this paper we present the result of a case study on the switching overvoltage transients of ac electrified railroad trains equipped with switch-type rectifiers in Taiwan Railway Administration (TRA). It was found that new generation of switch-type converters could result in significant over-voltage of magnitude comparable to lightning surge if no proper snubber circuit be used. The switching surge could damage power equipment of nearby trains in the same service zone, as observed in the TRA system. It is recommended that maximum tolerance of switching over-voltage be clearly specified in the procurement phase of new trains with switch-type converters then accurately verified in the commissioning phase to ensure proper preventive measure be installed.