Research On The220kV/3kA Cold Dielectric HTS Cables Termination

The characteristic of High-temperature superconductors (HTS) operating at liquid nitrogen temperature (77K) makes the superconducting technology from the research stage into the commercial application stage. HTS cable, one of its applications in engineering, can carry high current density with zero resistance, so that it has a series advantages such as low loss, small size, large transmission capacity, no fire hazards, etc., and is suitable for short distance transmission of electricity and power plants, substations. At the same time, with the electricity of large cities rapid increasing, HTS cable system can be used to replace the existing transmission system to meet the dramatic increase of electricity for the city. HTS cables can be divided into warm dielectric (WD) and cold dielectric (CD) in accordance with their insulation structure. The design of cold dielectric HTS cable terminations, which is one of the most important techniques of HTS cable.The termination, as an important part of the high temperature superconducting cable, plays a crucial role in the steady operation of the HTS cable system. With the development of termination technology, the level of voltage and transmission capacity, the research and design of the termination are also continuously developed. Due to the advantages of the cold insulation HTS cables compared with room temperature HTS cables, most of the HTS cable projects under construction are cold insulation HTS cable. Therefore this paper will simply introduced the change and the development of the cold insulation terminations, simply describe the structure of various terminations, then explore the research and design of high voltage level of HTS cables termination.In this paper, we will discuss the design and research of220kV/3kA cold insulation high-temperature superconducting cable terminal. Due to the high voltage level, the structural design of the termination such as current leads, high voltage insulation face new technical issues, the structural design should redesign based on the existing technologies to meet the needs of220kV superconducting cable. Meanwhile, the thermostat and liquid nitrogen circulation system of termination also need to be redesigned to accommodate the significant increase of the heat leak from the high voltage level, and meet the stable economic operation of the superconducting cable system.