Zikai Wang

Test Results of 52/68 kA Trial HTS Current Leads for ITER

High Temperature Superconductor (HTS) current leads provide the transition of the current transfer system from room temperature to the 4.5 K. For the ITER superconducting magnet system, a total of 60 HTS current leads are required, with a total nominal current capacity of 2.64 MA. By the use of HTS leads significant power savings can be achieved during the operation of the ITER magnet system. Based on the functional specification by the ITER Organization (IO), ASIPP manufactured and tested a first pair of trial HTS current leads for the ITER coils. The cryogenic test of these 68 kA and 52 kA trial HTS leads was performed at ASIPP using the cryoplant and power supplies of the EAST Tokamak. The following paper presents the results of the tests and concludes with a discussion of the design features of the next generation prototype of the ITER HTS leads based on the results of the trial lead tests.

Design of the ITER TF Magnet Feeder Systems

The International Thermonuclear Experimental Reactor (ITER) superconducting magnet system requires current supplies from 10 kA to 68 kA. The components relating the electrical power and cryogens through the warm-cold barrier to the ITER magnets are the so-called feeders. In total there are 31 such feeders for the ITER magnet system, 9 of them necessary for the toroidal field magnet system are called TF feeders. Each feeder consists of three main units: the In-Cryostat Feeder (ICF), the Cryostat Feed-Through (CFT) and the S-Bend Box (SBB)/Coil Terminal Box (CTB) assembly. This paper presents the latest design of the TF feeder components.

Development and Test of 10.5 kV/1.5 kA HTS Fault Current Limiter

Superconducting Fault Current Limiter (SFCL) is an attractive appliance for modern electrical power system. A 10.5kV/1.5 kA three-phase HTS fault current limiter was developed by IEE, CAS. This improved rectifier-type SFCL with HTS coil of 6.25 mH is going on a demonstrated long-term reliable operation in a real 10.5 kV substation located in Hunan, China. In a three-phase-to-ground short circuit test of grid, the prospective fault current of 3.5 kA was limited to 635 A at the pre-setup short-circuit point successfully

Fabrication and Tests of a 1 MJ HTS Magnet for SMES

In this paper, the design, fabrication and tests of a I MJ HTS magnet for SMES was presented. The magnet was fabricated by BSSCO tapes, it consisted of 44 pancakes, the inner diameter of the winding is 400 mm, the outer diameter is 568 mm and the height is 648 mm, the inductance is 6.38 H and the rated operation current is 560 A at 4.2 K. The tests show the magnet could be operated at the design parameters. The magnet will be used for the 1 MJ/500 kVA SMES unit which will be demonstrated at a 10 kV substation in Beijing.

Design, Fabrication, and Tests of Three HTS Coils for a Model Fault Current Limiter

The design, fabrication and tests of three high temperature superconductor (HTS) coils for a rectifier-type model fault current limiter (FCL) were presented. The field distributions in the coil were numerically analysed by FEM. Based on the field distributions and the strong anisotropic characteristics of Bi2223/Ag tape, the HTS coils were designed and fabricated. The inner diameter and the height of the coils were 80 mm and 94 mm, respectively. Each of the coils consisted of 8 double pancakes. Every double pancake consisted of 103 turns with 35 meters of Bi-2223/Ag tape. After the characteristics of the coils were tested in liquid nitrogen, three of the coils were assembled in their nonmetallic-material cryostats and works with the model FCL.

Development and Test of a Superconducting Fault Current Limiter-Magnetic Energy Storage (SFCL-MES) System

A superconducting fault current limiter-magnetic energy storage (SFCL-MES) system for substation applications is proposed. SFCL-MES system can limit not only the peak fault current, but also the steady fault current. Moreover, it can provide high-quality power for the critical customers of the substation at the same time. A 100 kJ/1000 A/20 kVA SFCL-MES prototype system is developed, and it mainly consists of a NbTi magnet with two coaxial and homocentric solenoids for reducing stray field, a three-half-bridge converter and a current regulator. The principle of SFCL-MES is analysed, the design and experiment results for the SFCL-MES system are described.

Development and Demonstration of a 1 MJ High-Tc SMES

A superconducting magnetic energy storage system (SMES), with stored energy of 1 MJ and compensation power of 0.5 MVA, has been developed successfully, and now is operating at the worlds first superconducting power substation at Baiyin National High-Tech Industrial Development Zone, Gansu Province, China. The SMES employs a high Tc superconducting magnet, which consists of 44 pancakes, operates at 4.2 K in liquid helium, and is cooled down by 4 G-M cryo-coolers. The SMES connects to a 10.5 kV power grid by the use of a power conversion system. Since 16 February, 2011, the SMES has been operating reliably, and providing good-quality power for three companies.

Design of a 1 MJ/0.5 MVA HTS Magnet for SMES

SMES is a potential solution for power quality issues. The development of a 1 MJ/0.5 MVA SMES is now at its final stage and the device will be put into operation in a live power grid of 10 kV in late of 2006 at a substation in the suburb of Beijing, China. The design and analysis of the SMES coil has been completed and magnetic flux density distribution of and electromagnetic force on the coil has been analysed by means of FEM. The cryogenic system adopts bath cooling method and employs four cryo-coolers to re-liquefy the evaporated helium. And HTS current leads are utilized to reduce heat loss.

The Electromagnetic Analysis and Structural Design of a 1 MJ HTS Magnet for SMES

An HTS magnet was designed and fabricated for the 1 MJ/0.5 MVA SMES. It consists of 44 double pancakes with an inductance of 6.28 H, and the rated operating current is 565 A. In this paper, the electromagnetic analysis and the structural design of the magnet are presented. Because of the strong anisotropy of Bi2223/Ag tape, the field distribution can seriously affect the performances of the magnet. Its magnetic field distribution is analysed by means of finite element method (FEM). Similarly, the critical current (Ic) distribution of each turn in the magnet is also calculated. Based on the analyses and calculations, the structural design of the magnet for 1 MJ/0.5 MVA SMES is finished. In order to obtain a uniform current distribution between co-wound tapes in the same double pancake and among the parallel connected double pancakes, special methods are developed for the structural design.

Winding Design and Electromagnetic Analysis for a 1250-kVA HTS Transformer

Because high-temperature superconducting (HTS) coils possess low-resistivity, large-current-carrying, and state transition characteristics, the design of HTS transformers is much different from that of conventional ones. The general design of 10.5-kV/1250-kVA HTS transformer is given first. In the electromagnetic design of the 1250-kVA HTS transformer windings via field-circuit coupling simulation, the influence of leakage magnetic field on the critical current of tapes and the circulating current of parallel branches was considered. Moreover, the transient stability of transformer windings combined with superconducting fault current limiter in the HTS power substation is discussed. Based on electromagnetic analysis, the primary and the secondary windings are constructed, and a special transposed method for double pancakes wound with four parallel tapes is proposed. Finally, the current-carrying ability of the primary and the secondary windings is tested in 77 K. Their critical currents are higher than 200 and 3200 A, respectively, which is enough in rated operating condition.