Undersökning av linjespänning vid återmatande bromssystem i spårvagn M31

Abstract

This report is a study in voltagelevel in connection with regeneration of brake energy from the tramtype M31 in Gothenburg. In the act of braking, the tram M31 uses electrical braking where the electrical motors generates energy and if possible send it back to the overheadline, where other trams in the nearby can use this regenerated energy for its own driving force. In cases where no other energyconsumers are located in the same section, there is a resistance witch task is to convert this energy into heat. The regulation of this resistance appears to cause an increase in the voltagelevel into far too high levels. Investigations of the trams regulationequipment and its construction have been done. Further have measurements on the overheadline been performed in order to map the voltagevariations during a longer period of time. The result have been showing that the voltagelevel during regeneration often is as high as 880V-920V, more extreme values have not been observed in a large scale. The values are especially high compared to the nominal voltagelevel. An other problem is the big variation in voltage, where the voltage pulsates between 750V and 900V.