Implications of faults on insulation coordination of dedicated metallic return on bipolar HVDC overhead transmission lines


This paper focuses on a specific issue of bipolar HVDC lines with a dedicated metallic return (DMR). DMR is insulated to a lower level than the pole and its insulators are shorter. One event, for example, pole-to-ground-fault will cause a fault on both the pole insulation and the DMR insulation simultaneously because the DMR insulation fault will be supported by the DC current and will turn into a DC arc. To ensure independent pole operation, these types of events should be avoided or, if the DMR does flashover, to extinguish the fault as soon as possible. This is studied through the paper and different solutions are tested to protect the DMR.

Hart Domagoj, R. Courtellemont , A. Xemard , A. Bertinato 

Published in Electric Power Systems Research