Core Insights - The Zhejiang Zhoushan 500kV interconnected transmission and transformation project has undergone its first simultaneous double-line maintenance, marking it as the highest voltage level cross-sea transmission line in the world [1] Industry Developments - The maintenance involves removing the oxidation layer from the wire surface to eliminate potential hazards, supporting a key energy project and grid access work in Zhejiang Province [1] - Maintenance personnel have over 10 years of experience and have undergone professional training, ensuring safety measures are in place [1] - New technologies such as heavy-duty drones for material transport and high-altitude X-ray inspection equipment have been introduced, enhancing the maintenance process [1] - Despite technological advancements, minor defects still require manual inspection by maintenance personnel [1]