• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
• /
• 2003.02a
• /
• pp.250-253
• /
• 2003

Rise of the current level at power applications, such as, transformer, motor and power cable, need for using stacked HTS tapes. In this paper, we measured losses of the stacked HTS tapes. Three different types of the stacks which were made of 2 tapes, 3 tapes and 4 tapes, were tested Perpendicular magnetic field was applied to the HTS stacks as the external magnetic field. Effects of the gap between HTS tapes were examined.

• KEPCO Journal on Electric Power and Energy
• /
• v.1 no.1
• /
• pp.145-150
• /
• 2015

This paper described the medium voltage high temperature superconducting cable thermal simulation and its application. New simulation method for HTS cable modeling using PSCAD/EMTDC is introduced in this paper. The developed simulation method consists of electrical model part and thermal model part. In electrical model part, power loss and thermal capacitance can be calculated in each layer, then the temperature of each layer can be calculated by power loss and thermal capacitance in thermal model part. This paper also analyzes the electrical and thermal characteristic in the case of normal operating condition and transient including single line to ground fault and line to line ground fault using new simulation method.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.56 no.9
• /
• pp.1535-1542
• /
• 2007

HTS (High Temperature Superconducting) Power devices has the several useful characteristics from the technical and economical viewpoint. Possible application to the utility industry have been widely discussed in various research projects. For the successful introduction of HTS power devices into power system, establishing a proper R&D and marketing strategies through estimating the future market size are necessary. However, quantitative estimates of how well HTS power devices will serve their markets have been lacking. In this paper, we propose a estimation methodology of future market size for HTS power divices such as cable, transformer, generator, and motor, and also evaluate the future international and domestic market size by using proposed methodology.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
• /
• 2003.10a
• /
• pp.193-196
• /
• 2003

This study aims at analyzing a power system, in case of installing HTS cable in the system First of all, we determine the case that HTS cable can be applied to KEPCO systems and analyze the static state of power system. Then we propose a solution of the problem resulting from the analysis.

• 한국초전도학회:학술대회논문집
• /
• v.13
• /
• pp.83-83
• /
• 2003

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.14 no.3
• /
• pp.141-148
• /
• 2015

The cryogenic cooling system should maintain the HTS power cable below 77 K. As the length of HTS power cables has increased, there have been many efforts to develop large capacity cryocoolers. Brayton, Joule-Thomson, and Claude refrigerators were considered for the large capacity cryocooler. Among the various cryocoolers, the Brayton refrigerator is the most competitive in terms of the HTS power cable. At present, it is thought that a 10-kW class refrigerator will be able to be used as a unit cooling system for the commercialization of HTS power cables in the near future. The Brayton refrigerator is composed of recuperative heat exchangers, a compressor, and a cryogenic turbo expander. Among the various components, the cryogenic turbo expander is the part that decreases the temperature, and it is the most significant component that is closely related with overall system efficiency. It rotates at high speed using high-pressure helium or neon gas at cryogenic temperatures. This paper describes the design of a 300-W class Brayton refrigeration cycle and the cryogenic turbo expander as a downscale model for the practical 10-kW class cycle. Flow and structural analyses are performed on the rotating impeller and nozzle to verify the efficiency and the design performance.

• Proceedings of the KIEE Conference
• /
• 2000.07b
• /
• pp.810-812
• /
• 2000

Superconducting transmission cable is one of interesting part in power application using high temperature superconducting wire as transformer. One important parameter in HTS cable design is transport current distribution because it is related with current transmission capacity and loss. In this paper, we calculate inductance and current distribution for 4-layer cable using the electric circuit model and compare calculation results of transport current losses by monoblock model and Norris equation

• Progress in Superconductivity and Cryogenics
• /
• v.10 no.2
• /
• pp.34-37
• /
• 2008

According to the recent design of an HTS (High Temperature Superconducting) power transformer whose capacity is hundreds MVA, the rated current values of the low voltage side are generally over thousands amps. Considering the performance of the recent HTS wires, it is inevitable to use several HTS wires in parallel for large rated current. Lots of stacked HTS wires were fabricated and tested so far, and the results have showed that we have to transpose each wire in order to reduce the AC losses as well as to increase the current capacity. But many development programs about HTS transformers reveal that the transposition of the several wires during the winding process is quite difficult not only in case of the layer windings but also in case of the pancake type ones. So, we need transposed multiple HTS wire which we can handle like single wire or cable for the HTS windings of large capacity power transformer. We fabricated several kinds of samples of multiple HTS wire with transposition to apply it to the HTS windings of power transformer. The electrical characteristics such as critical currents or AC losses are analyzed by experiments in case by case. Finally we present the best design of a multiple HTS wire for power transformer.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
• /
• 2003.02a
• /
• pp.224-227
• /
• 2003

According to the increasing power demands for the power transmission of major cities, HTS power cables which have large current capacity and low power loss will be needed. In this paper we have studied breakdown voltage properties of paper/liquid composite insulating system for HTS cable insulation. And we measured the dielectric loss(tan$\delta$) of mini-model cable. From results, the insulation paper-ice composite insulation system is thought to be one of good candidate for the electrical insulating system at cryogenic temperature.

• Progress in Superconductivity and Cryogenics
• /
• v.15 no.2
• /
• pp.44-47
• /
• 2013

Large AC loss from the second generation (2G) high temperature superconducting (HTS) wires has been one of the major bottlenecks in power applications with HTS materials. Moreover, the large power applications also require the large current capacity from the HTS wires, which makes them produce larger AC losses. In order to reduce the AC loss from the HTS conductors with large current capacity, an HTS compact cable with some striations on the superconducting layers has been proposed. In this paper, we prepared some sample HTS compact conductors with striations, and measured their magnetization loss from the external magnetic field. We also made some slits on the superconducting layer of the HTS wire by laser cutting to reduce the aspect ratio of the superconducting layers. It would make the low eddy current loss and magnetic decoupling. Finally, the magnetization losses of the sample HTS compact conductors were measured and analyzed.