Introduction: The scope of this research is focussed on HVDC mass impregnated (MI) cables stress processes that are particularly vulnerable in the cooling stages associated with power reductions or emergency shut downs, especially when occurring during the delivery of short term overloads.

Objectives:

To determine what load conditions (power ratings and load patterns) typical high voltage direct current (HVDC) mass impregnated paper insulated cables can be subjected to without risking cavity-induced dielectric breakdowns during a cool-down period after a power reduction or turn-off.

To establish an informal North Sea cable working group collaboration on HVDC link projects, potential sharing of spares holding and repair resources.

Expected Benefits:

• Obtain a detailed physical understanding of the processes that lead to cavity formation and the importance of various operational, environmental and cable design parameters to these processes.

• Develop a numerical model that quantitatively describes the radial mass flow and cavity formation under load cycling.

• Determine the operational constraints for one or more HVDC subsea cables presently in service.