Nantong, July 29, 2017, ZTT Group - leading global manufacturer of cable systems, announced that China’s first ±525kV XLPE insulated flexible DC cable system had been successfully developed. This is another successful breakthrough of ZTT after its development of ±160kV, ±200kV, ±320kV DC cable and 500kV AC submarine cable.
According to Dr. Fu Mingli, Senior Technical Expert of South Power Grid Science Research Institute introduced, at present, only a few countries such as Sweden, Italy, Norway and Japan had the technology of ±525kV XLPE DC cable system. Even if they successfully developed the product, yet they do not have completely applied in reality. While with the development of offshore wind power in Europe and USA, and the plan of Super Power Grid with the backbone of flexible DC transmission, has provided a huge market prospect for HVDC cable. ZTT is also the only Chinese manufacturer invited by German TSO to participate in their planning of the first thousand km ±525kV XLPE DC cable line project.
In the field of EHV & UHV power transmission, flexible DC transmission mode is a new type of transmission technology. Compared with the traditional AC transmission mode, it has obvious advantages in cost, transmission loss, power control, system stability, operation safety and multi terminal access. Application of ±525kV XLPE DC cable system can achieve large capacity of thousands of kilometers of long-distance transmission, which is the most ideal way of power construction of offshore wind farm, EHV transmission network, isolated island power interconnection, intercontinental energy interconnection, etc.
Mr. Xie Shuhong, Professor Level Senior Engineer, Director of ZTT Research Institute and ZTT Submarine Cable Research Institute, introduced that ZTT began to research in 2015, together with Shanghai Jiao Tong University, Shanghai Electric Cable Research Institute, and Global Energy Interconnection Research Institute, etc., formed a high-level R&D team. The team has made a series of key technical breakthroughs in material testing, cable and accessory system design, performance parameter, manufacturing process and testing. In July 2017, the product had successfully passed type test of National Quality Supervision and Testing Center for Cables and Wires. During the testing, representative from potential clients (TSO) has visited and witnessed .
Mr. Yang Liming, Professor Level Senior Engineer, Deputy Chief Engineer of State Grid Electric Power Research Institute, addressed that, ±525kV flexible DC cable system developed by ZTT, represented the highest level of domestic insulated DC cable. It has four advantages, firstly, independently and successfully developed the largest cross-section of 3000 mm2 water resistance conductor, which opened up a new type of cable conductor technology, and had the highest voltage of 525kV in China. Secondly, transmission capacity is up to 3000MW, which has improved 135% compared to the current operation of ±320kV DC cable. Thirdly, it has accomplished integration of power transmission, optical fiber communication and real-time temperature measurement. Fourthly, technological breakthrough of new metal shield structure, which has decreased 10% diameter compared to corrugated aluminum type cable with the same voltage level and specification.
The successful development of 500kV AC submarine cable and ±525kV DC cable has further reinforced ZTT leading position in the field of domestic HVDC cable industry. ZTT will make further efforts to break through the key technology of global energy network, and apply these technologies on the construction of the Belt and the Road, to support independent capability of large capacity and long distance flexible DC transmission.
