Development and Standardization of 750 kV Extra-High-Voltage AC Cable System for Large Capacity Renewable Energy Transmission

To meet the urgent demand for large-capacity and high-reliability transmission equipment in pumped storage power stations and large renewable energy bases in Northwest China, this paper systematically carried out independent research and development as well as standardization studies on 750 kV cross-linked polyethylene (XLPE) insulated extra-high voltage cables. The research covers the structural design of the 750 kV cable system, manufacturing processes, and systematic test verification. Refined designs were performed for the conductor, insulation, buffer layer, metal sheath, and outer sheath, overcoming key processes such as conductor forming, thick insulation extrusion, and manufacturing of the smooth aluminum sheath cables and corrugated aluminum sheath cables. Through type tests, pre-qualification tests, and mechanical performance tests, the electrical performance, mechanical adaptability, and long-term operational reliability of the cable system were verified. This study has established a complete technical system and standard specifications, providing critical equipment support and solutions for the engineering application of 750 kV extra-high voltage cables and the construction of smart grids.