Insulation Studies and Experimental Results for High Tc Superconducting Power Cable

Tri-axial high temperature superconducting (HTS) power cables are being developed to maximize their advantages, which include reducing amount of HTS wires, having a lowleakage magnetic field, and being compact compared to different types of HTS power cables. However, a drawback of HTS power cables is their inherent imbalance impedance, which is due to an asymmetrical structure on each phase. To solve this problem, the phases must be transposed. The authors designed a distribution class tri-axial HTS power cable, as well as a transposition-based connection scheme for the cable. The phases of the cable were connected to each other via transposition through their crossconnections. This was achieved with an insulated support structure with three walled-off areas for insulation between three the phases, as well as transposition conductors, including copper base and HTS wires. In this paper, a distribution class tri-axial HTS power cable and a connection scheme for it are designed. The results, including the transposition-based joint box design, are described in detail. The connection scheme will be applied to the joint box of the cable for high-capacity and long-distance transmission.

Section: A Design Of the Electrical Insulationmentioning

confidence: 99%

Transposition-Based Connection Scheme and Joint Box Concept for a Tri-Axial HTS Power Cable

Kim

Dinh

Choi

et al. 2015

“…This is because the temperature and the resistance of the HTS tapes increased as the current increases. Moreover, the resistance of the HTS tape increases as the current at HTS tape increases [7].…”

Section: A Stabilizer and Current Redistributionmentioning

confidence: 99%

“…Therefore, the liquid nitrogen was maintained saturation state and it means that no bubble is generated by the fault current. When there was no stabilizer, whole fault current flowed through the HTS tape and the temperature increases much higher [7]. The required maximum temperature of the HTS power cable is about 84 K after the worst fault current considering the degradation of critical current and immediate re-entry of normal transport current.…”

Section: B Temperature Of Hts Tapes and Liquid Nitrogenmentioning

confidence: 99%

“…The core of the superconducting power cable adopts copper stabilizer to reduce the heat generation and temperature rise when large amount of the fault current is introduced. Because of the electric insulation, the HTS tapes of the cable core is wound by insulation layer such as laminated polypropylene (PP) paper, Moreover, the HTS power cable is cooled by subcooled liquid nitrogen at 5 atm instead of saturated liquid nitrogen to suppress the gaseous nitrogen bubble, which act as source of partial discharge [7]. The geometry of the core is somewhat complex and there are many unknown thermal properties.…”

Section: Introductionmentioning

confidence: 99%

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Investigation on the Thermal Behavior of HTS Power Cable Under Fault Current

Kim

Cho

Sim

et al. 2006

During the operation of HTS power cable, large fault current can be introduced to a HTS power cable due to several accidents. In this case, a circuit breaker limits the fault current to protect the HTS power cable just as conventional power cables. However, heat is necessarily generated until the circuit breaker operates and severe performance degradation or even burn-out can occur at HTS tapes. To ensure the safety against the fault current, thermal characteristic of the HTS power cable should be verified under the fault current. Several experiments with a simple cable are performed using an AC pulse power supply. During the experiment, the increase of temperature and current redistribution are measured for the various fault current conditions. Through the experiments, safety margin of Korean HTS power cable is verified and the allowable peak current is suggested.

“…HTS power cable can be modeled with an equivalent circuit as shown in Fig. 1 [1]. And the equivalent circuits can be represented by the matrix form as shown in (1) resistances, self inductances and mutual inductances of the corresponding layers, respectively [2].…”

Section: B Searching the Pitch Combinationsmentioning

confidence: 99%

Design of HTS Transmission Cable With Cu Stabilizer

Sim

Cho²,

Bae³

et al. 2006

Self Cite

More than three HTS cable development and installation projects are proceeded over the world. A 22.9 kV/50 MVA class HTS cable system has been developed in Korea during last 3 years. And the HTS cable system for commercialization will be developed and installed on the real or test power grid within 2 years. Every HTS cable system has to satisfy the fault-current specifications of the power grid in order to protect the cable itself from the fault current. HTS cable composed of HTS tapes has some capacity of enduring the fault current by bypassing the fault-current through its Ag-sheath. But it may not be enough. So, some Cu stabilizer is generally introduced inside the conductor layers and outside the shield layers of HTS cable core for some higher fault current grade. In this paper, the design method of HTS cable with Cu stabilizer will be introduced. And the fault current capacity of HTS cable and its eddy current loss generated from the stabilizer will be calculated. And the impedance change of HTS cable in the fault current state will be calculated.Index Terms-AC loss, fault current, HTS superconducting power cable system stabilizer, quench.