Yanfang Bi

Introduction of China's first live grid installed HTS power cable system

Chinas first HTS power cable project was started in the second half of 2002 and on site system installation was finished at Puji Substation of China Southern Power Grid in March, 2004. This cable system consists of three 33.5 m, 35 kV/2 kA/sub rms/ cables, six terminations, and a closed cycle liquid nitrogen cooling station. The conductors of the cables were made of 4 layers of BSCCO 2223 HTS tapes. Off grid field testing and live grid trial operation has been carried out since the completion of the installation. In this paper, we will report the key technical parameters of the system. Descriptions of the installation site, demonstration of the system installation, and results of testing and trial operation will also be presented and discussed.

Recent Main Events in Applied Superconductivity in China

With strong support from Chinese government bodies such as the National High Technology Research and Development Program of China, National Natural Science Foundation of China and the National Basic Research Program of China, the field of applied superconductivity in China has been developed in different areas. Especially in the fusion application area, the first fully-superconducting tokamak, EAST (Experimental Advanced Superconducting Tokamak), has been successfully constructed and commissioned in the last two years. Based on the requirement from the ITER project, high performance Bi-2223 HTS tape, and Nb3Sn and NbTi strands have been developed as well. In the area of HTS applications for electric power systems, R&D has been focused on superconducting power cable, superconducting magnetic energy storage, superconducting transformer, superconducting fault current limiters. In this paper, the recent progress in applied superconductivity in China is reported.

China’s 30 m, 35 kV/2 kA ac HTS power cable project

A project for a 30 m, 35 kV /2 kArms, 3 phase, warm dielectric HTS power cable system is underway in China. This system will be installed in the China Southern Power Grid at the Puji substation in Kunming, Yunan province, in 2004. We have carried out a series of experiments to investigate the possible winding angles and layer configurations of the cable conductor with Ag sheathed Bi-2223 tapes, different LN2 cooling mechanisms, termination configurations, and fabrication techniques. For better understanding of the basics of an HTS cable system and practising new fabrication techniques, a 4 m superconductor cable with terminations and a closed cycle cryogenic system was built and tested. In this paper, we give the detailed parameters of the 30 m cable system and the work plan of the project.

Progress of the Engineering Design for the HT-7U Steady-State Superconducting Tokamak

The HT-7U superconducting (SC) tokamak will have a long-pulse capability, a flexible poloidal field (PF) system, and auxiliary heating and current drive systems, and it will be able to accommodate divertor heat loads that make it an attractive test for the development of advanced tokamak operating modes. The greatest progress has been made on the engineering design of the HT-7U SC tokamak device, including the calculation and simulation of plasma shaping and control of the PF system as well as calculation and analyses of stress and deformation distribution on the main components caused by dynamic electromagnetic forces, vacuum pressure, temperature differences, etc. Significant research and development progress on the design and the testing of the cable-in-conduit conductor of the toroidal field and PF has been made. A test facility system for the SC magnets of HT-7U has been set up and operated.

The modifications of conductor design for HT-7U TF magnets

The Tokamak HT-7U project has been funded as a Chinese national project since 1998. The machine is designed by the Institute of Plasma Physics, Chinese Academy of Sciences (ASIPP). The main object of the project is to build a nuclear fusion experimental device with divertor configuration. It is a fully superconducting device, consisting of superconducting toroidal field (TF) coils and super-conducting poloidal field (PF) coils. This paper describes the design of TF conductors, including pool boiling cooled conductor (PBCC) and cable-in-conduit conductor (CICC). The CICC design is based on UNK NbTi wires made in Russia, cooled with supercritical helium. The other (PBCC) is based on SSC cables. Both versions can satisfy the design requirements. The modification of the conductor design including their main parameters, the configuration, and analysis of stability for both conductors are given.

A prototype 4m, 2kA, AC HTS power cable system

Publisher Summary This chapter presents the detailed parameters and structure of the prototype system, a 4m system with terminations and cooling system, which is prepared to enhance the understanding of the basics of a HTS cable system and to prepare the fabrication techniques and skills. The cooling system is a closed cycle system. The coolant LN 2 is pumped into the sub-cooling tank, then into the HTS cable and brings heat out, and discharging to the LN 2 pump tank. The LN 2 pump is a partial emission centrifugal type with a hermetically sealed motor. The motor is controlled by a variable frequency drive (VFD). This allows adjustment of the pump speed to produce any desired head and flow within the available power range. The pump is so designed that the pump housing and impeller are in LN 2 and the motor is at atmospheric conditions. The heat-leak of the cryostats and the epoxy pipe is tested by calorie method which means by the rate of evaporation of LN 2 . The ac loss of the cable is obtained by testing the current, voltage, and the phase angle between them. The heat from conductivity and joule loss of the current leads are gained through the verified mathematical models and some test results. Till now, 30m,35kV/2kA HTS cable system have been installed and some tests are also finished, the results will be released in the near future.

The development of 4 m HTS power cable

Superconducting cables offer the advantages of lower loss, lighter weight and smaller dimensions, as compared to conventional cables. A 4 m, 2 kA, AC, HTS cable system was developed for the purpose of study. The cable conductor was made of Bi-2223 tapes. A space maintained as a vacuum between two corrugated stainless steel tubes functions as a cryostat surrounding the superconductor. A closed cycle liquid nitrogen cooling system was exploited. The cable was matched with two terminations, which connect the cable conductor at cryogenic temperature to an outside common electric conductor at room temperature and offer a path for liquid nitrogen. A series of tests were carried out to verify the functions of the system. Important data were obtained which can be used for making longer HTS cable systems.