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Design of electromagnetic dampers is considered as one of
key factors determining SCGs' characteristics. In a recent
design of damper cylinders without damper support to get
economical SCGs in simple structure, called monolayer
type, an assumption in the former studies is inappropriate.
In the paper, some modification of explicit expressions on
SCGs' characteristics for recent design of damper cylinders
will be described. Some considerations on design of
damper cylinders for SCGs will be discussed as well.
TUA10PO09
Comparison of Insulation Test of Mini-Models with
Different Winding for a HTS Transformer
H-G. Cheon, J. Lee, S-H. Kim, Gyeonsang National
University; S-M. Baek, Changwon college.
Recently, universities and companies are developing a
power distribution and transmission class HTS transformer
that is one of the 21st century superconducting frontier
projects in Korea. For the development of the HTS
transformer, it is necessary to establish the dielectric
technology at cryogenic temperature such as insulating
design, cooling system, manufacture, compact, and so on.
Also, verification of insulating stability is one of important
dielectric technology. Thus, in order to the development of
electrical insulation design of the HTS transformer with
double pancake and Z continuous winding, we have been
discussed insulation composition of the windings and
investigated breakdown characteristics such as breakdown
of LN2, polymer and surface flashover on FRP and
breakdown-surface combination in LN2. Also we have
been designed and manufactured a bobbin that has spiral
slot for the Z continuous winding. The double pancake coil
and Z continuous winding mini-models have been
constructed from Kapton film insulated Cu tape which is
simulated HTS tape for 22.9kV class HTS transformer
using 0.1 % breakdown strength obtained by Weibull
distribution. The winding models were measured insulation
test such as ac (50 kV, 1min), impulse (154 kV, 1.2×50 ms
full wave, 3 times) withstand test and PD (50 pC at 22.9
kV) test. And its excellent performance was confirmed.
TUA10PO10
Design of 100 MVA HTS Transformer with YBCO
Coated Conductor Windings
S. Lee, W-S. Kim, S-Y. Hahn, Korea Electrical Engineering
and Science Research Institute; T. Chang, K-D. Choi, H-G.
Lee, G-Y. Hong, Korea Polytechnic University.
154 kV/22.9 kV, 60 MVA power transformer is one of
standards for power system in Korea. In downtown, most of
them are installed in basements of buildings. Though 150
% of current power load will be needed in 2017, it is hard to
find a solution for increasing the capacity of facilities,
especially for the power transformer. The idea which 100
MVA high-temperature superconducting (HTS) transformer
can replace 60 MVA conventional one without volume
increase is very attractive for the power company in Korea.
We designed 154 kV/22.9 kV, 100 MVA, 3 phase HTS
power transformer with YBCO windings for this purpose.
So the main target of the design is for the HTS transformer
to have same size and weight as the 60 MVA conventional
one. In Korea, 154 kV class three phase power transformer
is composed of 3 individual single phase one. The design
criteria which are considered for the single phase one can
be directly applied to the three phase one. We adopted
shell type for the core and continuous disk type for the
winding in order to limit the voltage stress within it. The
coolant for the windings was sub-cooled liquid nitrogen and
the cooling system for 3 phase transformer was designed
also.
TUA10PO11
Fabrication and Test of Multiple HTS Wire with
Transposition for HTS Power Transformer
W-S. Kim, S. Lee, S-Y. Hahn, Korea Electrical Engineering
and Science Research Institute; Y-I. Hwang, K-D. Choi, H-
G. Joo, J-H. Han, H-G. Lee, Korea Polytechnic University.
According to the recent design of an HTS (High
Temperature Superconducting) power transformer whose
capacity is hundreds MVA, the rated values of the low
voltage side current is over thousands amps. Considering
the performance of the recent HTS wires, it is inevitable to
use several HTS wires in parallel for large rated current.
Lots of stacked HTS wires were fabricated and tested so
far, and the results have showed that we have to transpose
each wire in order to reduce the AC losses as well as to
increase the current capacity. But many development
programs for HTS transformer reveal that the transposition
of the several wires during the winding process is quite
difficult not only in case of the layer windings but also in
case of the pancake type ones. So, we need transposed
multiple HTS wire which we can handle like single wire or
cable for the HTS windings of large capacity power
transformer. We fabricated many kinds of samples of
multiple HTS wire with transposition to apply it to the HTS
windings of power transformer. The electrical
characteristics such as critical currents, distributions of
current, breakdown voltages or AC losses are analyzed by
experiments in case by case. Finally we present the finest
design of a multiple HTS wire for power transformer.
TUA10PO12
Continuous Disk Type HTS Winding for High Voltage
Power Transformer
Y-I. Hwang, K-D. Choi, H-G. Joo, J-H. Han, G-W. Hong,
Korea Polytechnic University; W-S. Kim, S. Lee, S-Y.
Hahn, Korea Electrical Engineering and Science Research
Institute.
High temperature superconducting (HTS) windings for an
HTS transformer which have been developed have two
kinds of type, one is the layer type and the other is disk
type. The disk type windings have advantages over the
layer type ones for a power transformer such as good
insulation and limit of voltage stress. But this kind of HTS
winding generates excessive AC losses caused by strong
magnetic field component perpendicular to the surface of
the HTS wire. Nevertheless, the layer type windings have
adopted for an HTS power transformer so far because of
the small AC losses of the HTS windings. We propose a
new winding method for a high voltage HTS transformer
which has advantages of both types of HTS windings, and
we call it continuous disk type HTS winding. This new type
of HTS winding consists of pile of lots of HTS disk windings
which have no resistive joint between them. A prototype of
an HTS winding was fabricated by the new winding method
we proposed and characteristic test was carried out. The
test result shows that the new type HTS windings can be
applied to HTS power transformers, especially to the high
voltage ones.
TUA10PO13
Performance Evaluation for a HTS Transformer
A. Formisano, R. Martone, Seconda Università Napoli; F.
Marignetti, M. Scarano, Università di Cassino; G. Masullo,
A. Matrone, R. Quarantiello, CRIS.
The adoption of High Temperature Superconductors (HTS)
tapes is starting to become a suitable and interesting
alternative to copper for windings in transformers, thanks to
the improvement in performance and the lowering of costs.
Of course, designs different with respect to usual layouts
77 MT-19 2005, Genova