Field DC Voltage Withstand Test of Submarine Cable in Hainan Grid Connection Project

500kV Hainan Grid Connection project is the major project connecting Hainan Power Grid to Main China southern power grid. Submarine cable segment is a core part of the whole project. The safety and reliability of the whole project is directly determined by the situation of its main insulation. The submarine cable is affected by a variety of factors in the sectors of manufacturing, transportation and installation. Field voltage withstand test on the submarine cable is of great significance in order to check its insulation condition after installation. In this paper, field DC voltage withstand test of 500kV oil-filled submarine cable is researched. The data obtained in field trials is analyzed to evaluate the main insulation reliability. The results show that the manufacturing quality and the insulation condition installation after laying on site of the submarine cable is reliable, meeting the engineering requirements of safe operation.