Abstract Body

The combicable is a power distribution cable that consists of four main conductors used for transportation of the three phase AC power to the consumers. In the same cable, there are four auxiliary conductors situated around the main conductors and these are used for powering public lighting, traditionally with AC power. Recently, public lighting shifts towards LED lighting, requiring DC instead of AC. The question is if the four auxiliary conductors can be used for DC powering the public LED lighting, instead of adding a new underground cable for public LED lighting. Retrofitting the auxiliary conductors in existing combicable means a considerable saving in material and labor costs, as there would be no need for replacement of the cable for applying DC powered public LED lighting. Since the combicable has been widely applied in the Netherlands with over 40.000 kilometers of cabling, reusing these cables would save a lot of material and labor costs.
Some experimental research has been carried out to investigate whether it is possible to apply the combination of AC main power and DC power for the public lighting in the same combicable. Before implementation, the cross-coupling and electromagnetic interference between the AC and DC system has to be investigated to ensure reliability of the system. In particular the impact of transient voltages and currents in the AC section of the cable as a results of switching actions in the DC section of the cable.
To investigate this problem, a simulation model of the combicable is a valuable tool. In this paper, a set up of a simulation model for the combicable will be described that makes it possible to investigate and to observe the transient voltages in the cable during switching actions. The simulation results give insight in the behavior of the combicable when applying AC and DC simultaneously in the same cable.