Submarine cable capacitance effect is obvious, AC submarine cable connect to the grid by the offshore wind farm and onshore wind farm reactive voltage distribution characteristics, there are significant differences in fault characteristics, more prone to overvoltage problems, may damage the cable insulation failure. Therefore, it is necessary to study the electrical characteristics, control and protection technologies of offshore wind power transmission and grid-connected transmission systems such as submarine cable overvoltages and protection test methods after the use of submarine cables, laying a technical foundation for the reliable grid connection of offshore wind farms. In this paper, the submarine cable overvoltage impact test and suppression studies, found that arresters have a clamping effect on the submarine cable overvoltage, with the overvoltage amplitude increases, the arrester clamping effect weakened. No matter what kind of lightning arrester wiring, the impact of the first terminal amplitude the value is always lower than the end, that is, the arrester has a more obvious effect on the lightning impulse clamping at the beginning.