Insulation Properties of 250 KV DC XLPE Cables

The difficulty of obtaining the electric power generation sites close to the city forces us to install long transmission lines and to adopt dc transmission. During the execution of the Hokkaido-Honshu dc submarine cable project, 250 kV class XLPE dc cable was developed in parallel with self-contained oil-filled cables. While XLPE dc cable samples were subjected to a modified CIGRE Recommendation type test for a long term, insulation breakdown occurred frequently.