With the surging demand for long-distance, large-scale transmission of offshore wind power, a major breakthrough has been achieved in the localization of flexible DC cables, a critical component. The ±525kV DC cross-linked polyethylene insulated cable system independently developed by Zhongtian Technology Submarine Cable recently completed all its pre-qualification tests at the National Wire and Cable Quality Supervision and Inspection Center. The cable was subjected to a continuous voltage of up to 1.45 times its rated voltage for one year and passed stringent tests including thermal cycling, lightning impulse, and load impulse, fully meeting CIGRE standards. This milestone signifies that China has mastered the entire chain of core technologies—design, materials, and manufacturing—for the highest voltage class of flexible DC cables. It provides a localized solution for power transmission from large-scale offshore wind bases, such as those in the Guangdong-Hong Kong-Macao Greater Bay Area and along the Fujian coast, breaking the long-term monopoly held by European giants like Prysmian and Nexans in this field.