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Owing to the application of high-temperature superconductor (HTS) tapes, superconducting magnetic energy storage (SMES) magnets can be economical to run at temperatures around 20 K. The conduction-cooled SMES magnet has become a reality with the rapid development of cryocooler technology. In China, a 150 kJ/100 kW conduction-cooled SMES employed for power quality is now being developed by Huazhong University of Science and Technology (HUST) and Hubei Electric Power Company (HBEPC). In electromagnetic design, a hybrid structure that uses two kinds of HTS tapes is employed to increase the critical current, Ic, of the SMES magnet. This paper presents an electromagnetic and thermal design of the conduction-cooling system for the magnet. The relationship between Ic and temperature is analyzed, and the target parameters of the conduction cooling system are finalized. The design scheme of the cooling system is developed by analyzing thermal conductivity characteristics of HTS double-pancakes, thermal loads, thermal resistance, and cooling demands. Finite element analysis results show that the design scheme meets the requirements well in static conditions.

Thermal stability is an important issue to put high-temperature superconducting (HTS) power cables into practical use. Cooling system breakdown and fault current are the two major factors that might cause overheating or quench in HTS power cables. In this paper, a dynamical model of the HTS cable is built with the 3-D finite element method (3-D FEM), and the dynamic thermal characteristic under different operation conditions is analyzed. The computational results of this model can be used to evaluate the operation parameters of HTS cables and to set the action time of the relay protection system. The electrical and thermal parameters are based on the HTS cable, which is being manufactured in China.

For the magnet used in power apparatus, the inductance is an important parameter which may change the input-output characteristic of the apparatus. In research of the high temperature superconducting (HTS) magnet in energy storage system and other electric apparatus, we found the difference of the magnet's inductance between normal state and superconducting state. In this paper, the electromagnetic models of Bi2223/Ag tape and windings are established firstly. Based on the simulation analysis and measured results, the reason of inductance variation of HTS magnet has been clarified. The regularity of inductance variation of HTS pancake and magnet has been researched, and new requirement for the veracity in the process of superconducting magnet's design has been claimed.

This paper aims to study the feasibility of improving pulsed current output by using High temperature superconducting (HTS) air-core transformer. Based on the theoretical analysis, the simulations are done. Results of the simulations indicate that the HTS air-core pulse transformer can magnify the output current magnitude and accelerate the velocity of discharge. However, when a series of inductor modules use the same one HTS air-core transformer, the residual current may influence the discharging waveform. To eliminate residual current, self-coupling discharging model is proposed. The simulated and experimental results illustrate that a self-coupling model can eliminate the residual current effectively. The results of this analysis contribute to the research of superconducting inductor pulsed current output.

The anisotropy of electromagnetic performance of high temperature superconducting (HTS) tapes is significant. The performance of BSCCO and YBCO, both of which have been employed in industry already, is varied when they stand different orientations of magnetic field. In HTS magnet design, adopting optimization can directly affect the performance of magnet and the amount of the tapes employed in the magnet, namely affects the economy of magnets. Considering both the measurement results of magnetic field characteristics of the HTS tapes in the critical current and the technical requirement of the diminutive superconductor magnetic energy system(SMES) which is laboratory scale, this paper puts forward the technical scheme of making hybrid HTS magnet which employs both BSCCO and YBCO, then fulfills the optimization design of the hybrid HTS magnet by means of finite element analysis, which considers the performance of energy storing as constraint condition and the economical efficiency as destination. This paper verifies the superiority of employing two types of tape to make a HTS magnet.

Superconducting Magnetic Energy Storage (SMES) which is characterized by its highly efficient energy storage, quick response, and power controllability, is expected to contribute to the transient stability of power system. The energy function approach is frequently used as a convenient way to control or analyse the power system. Based on the dynamic characteristic of SMES, the interaction between the SMES and the power system is analysed. According to the additional damping provided by SMES, energy function based control strategy is designed to improve the transient stability of power system. Then, the functional range of the SMES power control is analysed, which can be utilized to optimize the allocation of SMES in power system. Simulation tests are performed to evaluate the performance of the proposed energy function based control method.

A 1-km, cold dielectric, high-Tc superconducting (HTS) power cable is being planned in China. The rated voltage and current are 110 kV and 2 kA, respectively. The termination, which connects the superconducting cable conductors at cryogenic temperature to a power transmission line at room temperature and an external cooling system at ground potential, is one of the crucial parts of the superconducting cable system. In this paper, such a termination is designed, including the current lead, the electrical insulation, the condenser cone and the SC-NC joint.

To research the key problems of storage energy and pulse forming in pulsed power, a pulse magnet made of Bi2223/Ag high-temperature superconducting (HTS) tapes applied in pulsed power experiment was developed. After determining electromagnetic characteristics of the magnet, a pulse forming network was designed. HTS magnet was immersed in liquid nitrogen bath, experiments were carried out about discharging pulse current to resistance load based on HTS magnet energy storage (SMES). The results show that pulse current waves were obtained through adjusted circuit construction and magnet parameters by acting delay of switches in the pulse forming network. The technical schemes about pulse forming based on SMES were presented.