Abstract: In response to the complex terrain characterized by "70% mountains, 10% water, and 20% farmland" in the coastal areas of southern Zhejiang, as well as the frequent occurrence of typhoons and salt fog, traditional manual operation and maintenance face challenges such as extensive visual blind spots, high operational risks, and delayed emergency response. This article addresses these issues by constructing a high-precision 3D laser point cloud model, enabling beyond visual line-of-sight (BVLOS) autonomous flight based on micro-terrain perception. By implementing a "segmented relay" operation mode, it overcomes the limitations of endurance and communication for long-distance power line inspections in mountainous areas. For typhoon disasters, an integrated emergency response strategy has been developed, encompassing rapid disaster assessment modeling, precise material delivery, and nighttime illumination. Application results show that, as of the end of 2024, this technological system has increased the coverage of inspectable areas in the region from 65% to 100%, achieving a defect identification accuracy rate exceeding 92%. This significantly enhances the operational resilience of coastal power grids under extreme environmental conditions.