(Photographed by Xinhua News Agency reporter Ding Ting)
In recent years, Suzhou City has been actively optimizing its energy structure and vigorously developing renewable energy power generation. To cope with the growing power demand and the proportion of new energy power generation access, simply increasing the density of the power grid contradicts the current situation of urban space saturation. Superconducting cables have zero resistance characteristics, can effectively improve power transmission efficiency, reduce energy loss, and become a solution to this problem.
China has made some explorations in the application of superconducting cables, but they were all AC superconducting cable demonstration projects. In recent years, with the accelerated construction of new power systems, a large amount of new energy power generation such as wind power and photovoltaic power generation has been connected to the grid, and DC loads represented by new energy vehicles have rapidly developed. Various places have begun to explore the construction of more flexible and controllable DC distribution power systems. Exploring the application of superconductivity in DC systems has gradually become a new research direction.
In June 2020, the Wujiang District Government of Suzhou City, Suzhou Power Supply Company, and Jiangsu Yongding Co., Ltd. jointly launched the construction of a high-temperature superconducting DC cable demonstration project. Based on the low-voltage DC distribution network in Tongli, Wujiang District, a high-temperature superconducting low-voltage DC cable with a total length of 180 meters was built, connecting the 10 kV Pangdong DC Center Station and the DC distribution room of Hongsheng Plastic Technology (Suzhou) Co., Ltd.
(Photographed by Xinhua News Agency reporter Ding Ting)
The designed voltage of this cable is ±375V, the current carrying capacity is 4500A, and the conductor cross-sectional area is 90 square millimeters, which is less than half of the cross-sectional area of conventional PVC copper core cables of the same voltage level. However, its transmission capacity is equivalent to 20 conventional cables, and the conductor loss is only one-tenth of that of conventional cables.
The superconducting cable system mainly includes the superconducting cable body, refrigeration system, and monitoring system. Inside the cable system, the liquid nitrogen inlet and outlet pipes of the cable body are connected to the refrigeration system through pipes to form a cooling medium circulation path for the superconducting cable. The monitoring system is the central control for operation and maintenance, ensuring the reliable and stable operation of the system. Outside the cable system, the cable body is connected to the busbar of the power grid line through a current lead, and is incorporated into the DC distribution power system to supply power to the DC load in the surrounding area.
It is reported that the Yttrium Barium Copper Oxide (YBCO) second-generation high-temperature superconducting tape used in the demonstration project is a Chinese-made material, realizing the localization of the core material of the superconducting cable system.
Article from: State Grid News Authors: Huang Lei, Zhu Qinghua
