Stories From China

Under the trend of large-scale development of offshore wind farms in China, the installed capacity of individual wind farms continues to increase from 500 to 1,000 MW or even higher. However, the cost of using the sea is increasing correspondingly because of the scarcity of offshore wind farm resources. The traditional 220-kV three-core submarine cable can no longer satisfy the engineering requirements of transmission capacity and economy. On August 17, 2023, the world's first 500-kV, three-core, cross-linked-polyethylene (XLPE)-insulated AC submarine cable was put into use. The submarine cable is applied to the Guangdong Yangjiang Qingzhou Offshore Wind Power Project (Phase I and II) with an installed capacity of 1,000 MW and two 60-km circuits. Compared with the singlecore 500-kV submarine cables, the three-core 500-kV submarine cables integrate the three-phase core and the optical cable into one. This integration has lots of advantages in area saving and cost reduction, but it also brings many technical problems due to the structural changes and the increase in conveying distance.