Nexans 33kv cables for onshore windfarm projects are now available with a conductive outer skin on the protective sheath, this innovative feature assists the installer in testing for sheath damage. This conductive outer skin feature represents one of Nexans Windfarm Innovations Program which covers a range of features for cables and associated services which can improve the overall efficiency of an onshore windfarm installation through reducing installation time and overall costs.
The cables used to convey power between the wind turbines and the collector substations are laid directly in trenches which can often cross challenging terrain. A common problem on sites is that the cable sheaths are damaged by stones or other obstacles during laying but this damage is not discovered until the cable is buried and testing is being carried out.
On standard cables, in order to make a ‘sheath test’ (which measures the resistance between the cables metallic screen and the outer sheath layer), the outer sheath needs to be in contact with moist soil/sand to provide a return electrode for the test. This means the test can only be performed satisfactorily once the cable is buried in the ground.