CEC Abstracts in PDF format (as of 7/3/07) - CEC-ICMC 2013

CEC 2007 - Abstracts
C2-R-04 Open cycle Joule-Thomson cryocooling with
prior sequential isentropic expansion
B-Z. Maytal, Rafael.
The high pressure stream outlets a gas reservoir and expands through
a loaded turbine prior to being fed into a Joule-Thomson (J-T)
cryocooler. Due to the load and according to its extent, the gas drops
its pressure through the turbine at a constant entropy process. On the
one hand, the gas that inlets the J-T cryocooler is of lower pressure
than without a turbine. This effect suppresses the integral isothermal
J-T effect which is the specific cooling capacity of the stream. On the
other hand, the isentropic expansion is accompanied by temperature
reduction which elevates the specific cooling capacity. This effect
dominates the former one thus consequently; the specific cooling
capacity is enhanced even when the high pressure gas reservoir stays
isothermal. The isentropic expansion is always accompanied by a
temperature drop which is quite substantial. Therefore, the expanded
very first cooled stream inletting the J-T cryocooler may significantly
accelerates the cooldown process.. This beneficial performance of the
serial arrangement of a turbine and a J-T cryocooler is analyzed and
formulated for argon and nitrogen according to any loading policy as
for instance, dropping the pressure at the turbine by a predetermined
constant factor.
C2-S Superconducting Cables
C2-S_01 The Latest Status of A Long Term In-grid
Operation in Albany HTS Cable Project
H. Yumura, T. Masuda, M. Watanabe, H. Takigawa,
Y. Ashibe, H. Ito, M. Hirose, K. Sato, Sumitomo
Electric, Industries, Ltd.
The HTS cable system is expected to be a solution for improvement of
the power grid, and three demonstration projects in the real grid have
been carrying out in the United States. The Albany Cable Project, one
of them, is to develop the 350 meters long HTS cable system with
capacity of 34.5kV, 800A, connecting between two substations in
National Grid Power Company`s grid.
A 320-meter and a 30-meter cable are installed into underground
conduit and jointed each other at a vault. The cable was fabricated
with Di-BSCCO wire total amount of 70km and has the structure of 3
cores-in-one cryostat. The cable installation of a 320-meter and a 30-
meter section was completed successfully with using the same pulling
method of a conventional cable. After cable installation, the joint and
two terminations were assembled at the test site. After the initial
cooling of the system, the completion tests such as the critical current,
heat loss measurement and DC withstand voltage test were conducted
successfully.
The in-grid operation was begun on 20th of July, 2006. And a long
term in-gird operation has been progressed satisfactorily at unattended
condition. In the Albany project, the 30-meter section is planed to be
replaced to YBCO cable in this spring. The development of YBCO
cable has been carried out by using SuperPower’s YBCO coated
conductors. This paper describes the latest status of the Albany cable
project.
C2-S-02 Deveopment of YBCO Cable for Albany HTS
Cable Project
H. Yumura, M. Ohya, Y. Ashibe, H. Ito, T. Masuda, K.
Sato, Sumitomo Electric Industries, Ltd.
The Albany Cable Project is to develop the 350 meters long HTS
cable system with capacity of 34.5kV, 800A, connecting between two
substations in National Grid Power Company`s grid.
In-grid operation with BSCCO HTS cable was begun on 20th of July,
2006, successfully. And a long term in-gird operation has been
progressed satisfactorily at unattended condition. The BSCCO cable
line consists of a 320-meter, a 30-meter cable, cable-to-cable splice in
vault and two terminations. In the Albany project, the 30-meter
section is planed to be replaced to YBCO cable in this spring. The
development of YBCO cable has been carried out by using
SuperPower’s YBCO coated conductors. The YBCO sample core was
fabricated and evaluated its electrical and mechanical properties in
order to confirm the cable design. The critical current of conductor
and shield were approx. 1.4 kA and 2.0 kA, respectively. They are
almost same as design value considering with tape’s Ic and the effect
of magnetic field. The ac loss of the sample was 0.4 W/m/ph at 800
Arms of 60Hz. The fault current test, 23kA and38cycles, was
conducted under open bath condition. The temperature rises at
conductor and shield were almost same as the ones of BSCCO core,
and no Ic degradation was found after the fault current test. This paper
describes the detail of test results for YBCO sample core and design
of YBCO cable for Albany Project.
C2-S-03 A Cooling System for Navy Degaussing Cables
J. Yuan, J. Maguire, D. Aized, A. Covel, American
Superconductor Co.
Degaussing cables are a vital part of today’s military ships.
Degaussing cables are utilized in most navy ships to reduce their
magnetic signature, thereby making them much more difficult to be
“seen” by magnetic sensors and by magnetically activated mines.
Current degaussing systems consist of a series of field-generating
loops and their installation involves running heavy copper cables
around the perimeter of the ship’s hull. High Temperature
superconductor-based degaussing cables provide many benefits as a
replacement for conventional, copper-based degaussing systems,
including lighter weight, lower operating voltage, lower installation
costs, higher energy efficiency and smaller size. In March 2006,
AMSC announced that it had demonstrated the successful operation of
the world’s first full-scale HTS degaussing cable for military ships.
The 40 meter long HTS degaussing cable produced 4100 Amp-turns
with a significant decrease in operating voltage to less than 0.5 volts,
or 1000 times lower than a comparable Amp-turn copper-based
system. The system has been continuing running since March, 2006.
This paper reviews the testing of the degaussing cable, along with a
comparison between the simulation and experiments.
C2-S-04 Performance Test of Cooling System for KEPCO
HTS Power Cable
H.S. Yang, D.L. Kim, B.S. Lee, Y.S. Choi, Korea Basic
Science Institute; S.H. Sohn, J.H. Lim, Korea Electric
Power Research Institute; H.S. Ryoo, S.D. Hwang,
Korea Electrotechnology Research Institute.
A cooling system for a 3-phase 100m HTS power cable with
22.9kV/1.25kA was installed and tested at KEPCO’s Gochang power
testing center in Korea. The system consists of a liquid nitrogen
decompression cooling system with a cooling capacity of 3kW at 66K
and a closed circulation system of subcooled liquid nitrogen. Several
performance tests of the cable system with respect to the cooling such
as heat load, AC loss and temperature stability, were performed at
operating temperature of 66.4K. Thermal cycle test, cool-down to
liquid nitrogen temperature and warm-up to room temperature, was
also performed to investigate thermal cycle influences. The outline of
the installed cooling system and performance test results are presented
in this paper.
This research was supported in part by the Electric Power Industry
Technology Evaluation & Planning office, Republic of Korea.
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