Analysis Of Dc Power Transmission Using High Tc

JOURNAL OF ELECTRONIC SCIENCE AND TECHNOLOGY OF CHINA, VOL. 6, NO. 2, JUNE 2008

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Analysis of DC Power Transmission Using High Tc Superconducting Cables
Jun-Lian Zhang and Jian-Xun Jin
Abstract⎯A conceptual superconducting DC cable model is designed and its magnetic fields distribution is analyzed with Ansoft/Maxwell soft. A DC Power transmission system is also studied by using theMatlab/Simulink. With the DC Line and AC Ground Fault, the system losses analysis is introduced.The analysis results mainly include the magnetic fields distribution of the HTS cable model with Ansoft/Maxwell, the system loss, the DC Line and AC Ground Fault with Matlab/Simulation. Index Terms⎯Ansoft/Maxwell, DC transmission system, HTS cable, power transmission loss. cable and the system model bebuilt.

2. Magnetic Analysis
Generally, a HTS cable of parallel configuration is used in superconducting electric power field and the current flowing in the HTS tape is unchangeable when the cable is operated under DC condition, therefore, there is only steady magnetic field existing between the HTS tapes. The magnetic field distribution in the HTS cable can be calculated by using finite-elementmethod (FEM). Ansoft/Maxwell soft is chosen to simulate the magnetic field distributions in and around the cold dielectric (CD) and warm dielectric (WD) HTS cables, where the HTS materials are assumed to be linear ones. The total current of the conductor layer is assumed to be 1 kA, and the relative permeability is assumed to be 1. 2.1 A Conceptual Cold Dielectric Cable Model The cold dielectric(CD) HTS DC cable has a concentric structure. The main body of this cable from inner to outer is former, compounded conductor, dielectric and compounded shield. Copper composed with parallel placed HTS tapes are used as compounded conductor and compound shield. The whole cable core is covered by a thermally insulated double wall cryostat. The LN2 goes through the hollow former and return at the otherend in the space between the outer layers of HTS tapes and below the cryostat. The main parameters of the CD cable are shown in Table 1.
Table 1: Dimension of the CD cable model Name LN2 Former Insulator1 Cu1 Conductor(YBCO HTS tape) Cu2 Insulator2 Outer Radius (mm) 8 9 9.4 10.5 10.8 11 12 13 13.3 13.5

1. Introduction
The 21 century is the age of superconducting cable, some of thetraditional grounding cables could be substituted with high temperature superconducting (HTS) cables before 2020. The resistive energy losses consumed on power transmission lines become enormous as the high capacity delivery power required by our dramatically developed society. Using HTS technology is an alternative way to resolve the principal technical difficulties to achieve high efficient powertransmissions. The HTS cable will especially benefit to DC power transmission due to zero resistive loss and lowering voltage levels. The DC networks can operate with low voltage and high current allowing direct connection of the generators to the rectifiers, eliminating the need for high voltage insulation and transformers[1]-[3]. In this paper, HTS cables and their application to develop a DC powertransmission system with the advantages of large transport current capability, no resistive loss and compact systems will be studied and identified. Technical assessments of DC electrical power transmission system behaviors with the use of HTS DC cable technology will be carried out with the HTS DC
Manuscript received March 15, 2008; revised April 30, 2008 J.-X. Jin and J.-L. Zhang are with School ofAutomation Engineering, University of Electronic Science and Technology of China, Chengdu, 610054, China (e-mail: jxjin@uestc.edu.cn, junlianz@163.com).

Cu3 Shield(YBCO HTS tape) Cu4

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JOURNAL OF ELECTRONIC SCIENCE AND TECHNOLOGY OF CHINA, VOL. 6, NO. 2, JUNE 2008

Fig. 1 illustrates the simulated results of magnetic field distributions of the CD cable model in Ansoft/Maxwell,...