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temporary voltage dips and interruptions, most frequent
grid malfunctions causing fault of the beam magnetic
confinement system. The innovative part of the prototype,
which also includes several sophisticated power electronics
items, is a 3 MJ stored energy magnet, wound with a new
low-losses NbTi cable, cooled by liquid Helium at 4,2 K and
adopting an electric insulation design solution to withstand
8 kV and obtain very close contact between coolant and
coil. New design hybrid Current Leads, made of a resistive
Copper stage and a High Temperature Superconducting
one, cooperate together with a set of three cryocoolers and
a multi-shield cryostat to keep negligible the Helium loss
amount. Electrical insulation of the most critical
components and the quench detection system is extremely
accurate, because the voltage at coil-ends rises up to
2.500 V. The experimental results obtained at Elettra
during the beginning of the SMES commissioning phase
are presented.
THM2OR2
Validation of the High Performance Conduction-Cooled
Prototype LTS Pulse Coil for UPS-SMES
T. Mito, H. Chikaraishi, R. Maekawa, T. Baba, NIFS; A.
Kawagoe, F. Sumiyoshi, Kagoshima University; K.
Okumura, R. Abe, Technova Inc.; T. Henmi, Graduate
University for Advanced Studies; M. Iwakuma, Kyushu
Univiersity.
We have been developing a 1 MW, 1 sec UPS-SMES for a
protection from a momentary voltage drop and an instant
power failure. A conduction-cooled low temperature
superconducting (LTS) pulse coil has excellent
characteristics, which is adequate for a short-time
uninterruptible power supply (UPS). The LTS coil has
better cost performance over the HTS coil and the
conduction cooling has higher reliability and easier
operation than the conventional cooling schemes. To
demonstrate the high performances of the LTS pulse coil is
a key technology of the UPS-SMES, we have fabricated a
prototype LTS pulse coil with stored energy of 100 kJ and
have conducted cooling and excitation tests. The coil was
cooled from 300 K to 4 K within 3 days, which indicated the
excellent thermal characteristics of this coil. Steady-state
operation at the rated current of 1000 A was verified and
over current test of 1230 A was also confirmed. Current
shut-off test from 1230 A with a time constant of 1.37 s was
successfully performed without normal transition. The
temperature rise in the coil was limited to 0.8 K, which
indicated a sufficient safety margin for the rated pulse
discharge from 1000 A to 707 A in 1 sec. Repeated
excitation of a triangular waveform with the peak current of
1000 A and ramp rate of 50 A/s was also tested. The
temperature rise in the coil was limited to 1.1 K, which
shows availability of continuous pulse operation because of
the outstanding heat removal characteristics of this coil.
THM2OR3
Design Consideration of a High-Temperature
Superconducting Magnet for Energy Storage in an
Active Power Filter
C. Chao, C. Grantham, School of EE&T, University of New
South Wales.
Installing active power filters (sometimes called active
harmonic filters or line conditioners) in an electric power
network can improve the quality of electricity supply. A
shunt active power filter, with a current-source PWM
inverter and a conventional copper inductor as its energy
storage has a significant power loss. The power loss in this
copper inductor can be substantially reduced by replacing
the inductor with a high-temperature superconducting
(HTS) magnet. Several solenoid design alternatives using
silver-sheathed BSCCO-2223 tape have been made for the
HTS magnet that has an inductance of 0.5H for this
application. A liquid-nitrogen-cooled HTS magnet has been
built and tested for use in an active power filter. The loss
reduction effect of using the HTS magnet with the currentsource
active power filter has been investigated
experimentally and the results are compared with those
when using a conventional copper inductor. Practical
issues such as air-core design versus iron-core design and
using liquid-nitrogen cooling or a cryocooling are analysed
and discussed.
THM2OR4
Superconducting Fault Current Limiter-Magnetic
Energy Storage (SFCL-MES) for Substation
Applications
C. Zhao, L. Xiao, L. Lin, Y. Yu, Institute of Electrical
Engineering, CAS.
In this paper, a new concept of Superconducting Fault
Current Limiter-Magnetic Energy Storage (SFCL-MES) for
Substation Applications is proposed. By replacing the bias
power source of bridge SFCL with the current regulator of
SMES, SFCL and SMES are integrated into FCL-SMES
with just one superconducting coil. The principle of FCL-
SMES is analyzed first, then its configuration and operation
mechanism are presented. FCL-SMES can not only limit
the peak fault current, but also limit the steady fault current
for long time. Moreover, it can provide high-quality power
for the critical customers of the substation at the same
time. Its effectiveness is verified by the numerical
simulation and experiment.
THM2OR5
Flexible Power Interconnection with SMES
S. Nomura, H. Tsutsui, S. Tsuji-Iio, R. Shimada, Tokyo
Institute of Technology.
Electric power systems are usually interconnected with
each other through a back-to-back direct-current (DC) link
to increase reliability of electric power networks and to
improve system operations. The objective of this work is to
discuss the concept of a Superconducting Magnetic Energy
Storage (SMES) system incorporated into a back-to-back
interconnection. In this case, the back-to-back system is
used as a power conditioning system for the SMES coils.
Since the AC/DC converter can be designed independently
of the frequency of the power system, a two-way switch is
connected to the AC side of each converter. This two-way
switch can select the interconnected power system. By
using the two-way switches, this system can increase the
availability factor of the back-to-back system during the
SMES operations and also enables the economical power
interchange between interconnected power networks with
an optimal time interval for the power demand of each
interconnected power network. This work discusses the
system configurations and operations of the back-to-back
interconnection with SMES that enables the replacement of
a pumped hydro storage system. In this case, the SMES
system is composed of a number of superconducting coils
in order to reduce the cost of the superconducting coil by
the effect of mass production. In this work, the SMES coils
are optimized from the required mass of the structure and
the leakage magnetic field.
MT-19 2005, Genova 120