Influence of Polarity Reversal on the dielectric strength of extruded HVDC Cables

The number of HVDC transmission lines has been increasing in recent years due to the need to integrate renewable resources, countries’ cross-border interconnectors, and to reinforce the electricity network. In LCC-based HVDC systems, the power flow direction is governed by reversing the operating DC voltage polarity. In the presence of space charge, voltage polarity reversal can locally enhance the electric field, thereby accelerating the aging of HVDC cable insulation and ultimately leading to premature dielectric breakdown. In the literature there has been a significant focus on lifetime models, space charge measurement and consequently electric field calculation via numerical or analytical methods. However, less attention has been paid to experimental dielectric strength measurements…