Uniform Current Distribution Conductor of HTS Power Cable with Variable Tape-Winding Pitches

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.

Section: B Searching the Pitch Combinationsmentioning

confidence: 99%

Design of HTS Transmission Cable With Cu Stabilizer

Sim

Cho²,

Bae³

et al. 2006

“…Considering Ohmic-voltage drop such as flux flow voltage of the HTS tapes, we can derive a governing equation as follows: (1) where is the total magnetic flux through the loop and is the equivalent resistance in the -th layer. Considering magnetic flux in axial and azimuthal directions, we finally obtained the following governing equation:…”

Section: A Formulationmentioning

confidence: 99%

“…Reduction of AC losses is very important for realizing HTS cable and it had been reported that the same layer current controlled by twisting pitch and direction could reduce the AC losses effectively [1]. The combinations of cable parameters such as twisting pitch, twisting direction and layer radius for uniform layer current, however, exist infinitely.…”

Section: Introductionmentioning

confidence: 99%

AC Loss Reduction of Coaxial Multi-Layer HTS Cable

Tsuda

Fujimoto

Harada

et al. 2004

Reducing AC losses, cable size and cost of HTS tapes are required for the practical application of HTS power transmission line. We have theoretically investigated the relationship between AC losses and cable parameters such as layer radius and twisting pitch and direction in coaxial multi-layer HTS cable using our developed simulation method and revealed that the larger number of HTS tapes and twisting pitch are desirable for reduction of AC losses. In this paper we investigated influence of twisting pitch and direction on cable size and total amount of HTS tapes under a condition of constant AC losses. The diameter of each layer and total amount of HTS tapes in the cable with the same twisting direction are much smaller than those of alternate twisting direction. The cable with the same tape current would be better than that of the same layer current because of the smaller difference of the number of tapes per layer. In the cable with the same tape current, cable size decreases with the number of layers in spite of almost the same amount of total HTS tapes in the whole cable. In cable design, we cannot handle the restrictions of AC loss and load factor individually; it would be difficult to satisfy both the conditions of low AC loss and high load factor. AC losses could be reduced by increasing critical current of HTS tape without the restriction of load factor, while AC losses increases with the critical current with the restriction of load factor.

“…for (1) for (2) Here, is the twist pitch of th layer winding, radius from cable axis to center of th layer.…”

Section: A Inductance and Layer Currentmentioning

confidence: 99%

Magnetic field and magnetization loss calculation in an HTS transmission cable considering the axial field component of SC tape

Lee

Cha²

2002

One of the major issues in power application of the HTS transmission cable is the AC loss as it is related with power transmission capacity and efficiency. Although the HTS transmission cable has only transport current without external magnetic field, the magnetization loss as well as the transport current loss is generated because any tape constituting transmission cable is exposed to magnetic fields given by currents flowing in other tapes of cable. The magnetic field induced by layer flowing current in the transmission cable have two components, that is, axial component magnetic fields at inner region and azimuthal component at outer region of each layer for transmission cable axis due to winding structure of cable. Therefore, any tape in the cable experience parallel and axial component magnetic field for tape wide face. So, the magnetization loss must be calculated in consideration of this field configuration.Index Terms-HTS transmission cable, magnetic field component, magnetization loss, SC tape.