Long-Term Verification Test of a 275 kV3 kA REBCO HTS Model Cable
Shinichi Mukoyama, Masashi Yagi, Takaharu Mitsuhashi, Jin Liu
(Furukawa Electric)
Takeshi Ohkuma, Osamu Maruyama (ISTEC-SRL)
Naoki Hayakawa (Nagoya Univ.)
Xudong Wang, Atsushi Ishiyama (Waseda Univ.)
Naoyuki Amemiya (Kyoto Univ.)
Takayo Hasegawa (Showa Cable Systems)
Takashi Saitoh (Fujikura)
This work was supported by the NEDO in M-PACC project.
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HTS Cable projects in the world
Current [kA]
250MVA 500MVA
5
1000MVA
1500MVA
M-PACC,Y
15m
＊HYDRA (NY)
300m,Y（AMSC）
＊Columbus
200m,Bi
2.5
30m, Y
0
Barcelona
30m,Bi
＊CEPRI, Beijing
1000m,Y
＊Amsterdam
6km，Y
＊New Orleans
1760m,Y（AMSC）
0
KERI,LS‐cable
100m,Y
Y：YBCO
Bi：BSCCO
＊：in grid
20kV-2kA
Moscow, 200m，Bi
＊Soul
500m,Y（AMSC)
＊Albany (NY)
330m, Bi-Y
M-PACC,Y
30m
Furukawa
＊Bi実証
200～m
Super-ACE
500m, Bi
Furukawa
＊LIPA(NY)
600m, Bi-Y
Highest
Longest
100
200
300
Voltage [kV]
We can be available for any HTS cables with high current, high voltage, and DC.
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2
Merits of 275 kV HTS cable
・The capacity of the 275 kV HTS cable having 1.5 GW corresponds to a
typical overhead transmission line.
・The total loss of the 275 kV HTS cable becomes one-fifth of that of the
XLPE / OF cable.
50
HTS cable
Rating
voltage
275kV
275kV
Rating
capacity
1,500MVA
1,500MVA
(3 circuit = 9
cables)
(1 circuit = 3
cables)
Current
1.05kA×3
3.15kA
Transmis
sion loss
284 kW/km
59 kW/km
Outer
diameter
155mm×9
Cable construction cost [×0.1B\/km-cct]
XLPE cable 3cct
Overhead
40
Tunnel construction
土木費
Installation
布設費
line 冷却システム
Cooling system
ケーブル費
Cable
Manufacturing cost
ケーブル製作費
HTS wires
超電導線
30
53%低減
Decrease of 53%
20
HTS Cable
XLPE/OF
10
Cable
～1/5
150mm×3
Compact
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0
現用ケーブル
Conventional
cable
Conventional cable
超電導ケーブル
Superconducting
cable
Superconducting cable
3
Development of 275 kV-3 kA HTS cable
Technical Targets：
HTS Shield
Insulation
(1) Low Loss:
-AC loss and dielectric loss
<0.8 W/m at 3 kArms and 275 kV
(2) Design of Electrical insulation:
cable, termination and joint
(PD free at AC 310 kV, no BD at
impulse 1155 kV)
*[PD: Partial Discharge, BD: Breakdown]
(3) Endurance of over-current:
63.0 kArms for 0.6 s;
(4) Compact:
<150 mm (outer diameter)
HTS conductor
Cu (~25m)
Ag (~30m)
YBCO (~1.5m)
CeO2 (~1.0m)
Gd2Zr2O7
(~1.0m)
Hastelloy ~100m
structure of coated conductor (FJK)
Ic: 300 A/cm at 77 K
Wire made by Fujikura/Showa and SRL
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4
Development contents
2008～2010:
Fundamental technology and system design
・AC loss reduction
・Over-current test
・Design of electrical insulation
・Design of the cable system
2011:
Fabrication and Evaluation of Test Cable
・Fabrication
・Evaluation （Ic, Withstand voltage test ,
over-current characteristics）
2012:
Demonstration system
・275kV-3kA Cable fabrication
・Transportation (Japan→Shenyang, China)
・Installation (System construction)
・Verification test （Ic, AC current test, Withstand voltage test ,
AC loss and dielectric loss,
Long-term verification test)
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5
AC loss measurement
AC loss is reduced by using 3 mmW tape to suppress
the perpendicularity field on the tape.
Cutting method of tape has been improved to prevent
damege of cutting part.
HTS conductor at 2010
Ic=9200 A at 68.7 K
Ic=8550 A at 70.0 K
Ic=6700 A at 72.5 K
Ic=4700 A at 77.3 K
Calculation
-9
10
6
4
2
10
B
Substrate
The calculation: taking
Jc distribution into account
-10
0.235 W/m at 3 kA
6
4
HTS conductor at 2011
Ic=9020 A at 73.7 K
Ic=8150 A at 74.4 K
Ic=6270 A at 77.3 K
Calculation
2
10
-11
6
4
Critical current density (109 A/m2)
2
Normalized AC loss [J/m/cycle/A ]
2
Superconductor
30
25
20
Trapezoid
with 0.8 mm-shoulder
15
10
5
0
-5
-4
-3
-2 -1
0
1
2
Lateral positon (mm)
3
4
0.124 W/m at 3 kA
0.2
0.4
0.6
It(peak current) / Ic
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0.8
1.0
AC loss of the designed conductor
was low, 0.124 W/m at 3kA.
6
Investigation of insulation material(275kV HTS cable)
To reduce dielectric loss, pp laminated paper with a higher pp ratio of 60% was used.
Imp. B.D stress
99.99
99
90
70
50
30
70
1 mmt model cable No.2 &No.3
10 mmt model cable
B r e a k d o w n s t re s s [ k V / m m ]
Cumulative probability [%]
AC B.D stress
PDIE
10
5
3
1
0.5
0.3
0.1
18
60
V-t
n=49
50
n=50
n=50
40
65hで破壊
102hで破壊せず
PPLP-A (0.59 MPa(abs.))
PPLP-C(0.3
(0.3MPa(abs.))
MPa(abs))
PPLP-A
PPLP-C (0.3 MPa(abs.))
30
20
22
24
26
PD inception stress [kVrms /mm]
28
30
-3
10-3
-2
10 -2
-1
10 -1
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0
10 0
1
10 1
2
10 2
3
10 3
time [hour]
7
Design of 275 kV-3 kA HTS cable
Structure
Former
HTS conductor
Insulation
HTS Shield
Cu Protective
Protection
Cryostat pipe
Specification
Hollow stranded copper
2-layer YBCO
PP laminated paper
1-layer YBCO
Copper tape
Insulation paper
SUS and PVC sheath
Diameter
mm
35.4
Cu stranded former
HTS conducting layer
PP laminated papert
81.0
HTS Shield layer
Cu protection layer
88.0
150
Cryostat pipe
PE shieth O.D. 150mm
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88
275kV-3kA Cable fabrication
HTS core of 50 m
HTS core with cryostat pipe
In VISCAS
Cu hollow former
sample tests,
HTS conductor Ic, over-current,
withstand
Insulation
voltage tests.
30 m for demonstration
HTS Shield
Vacuum
insulation
PE φ150mm
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9
Testing condition
・Test conditions were decided as a shipping test and a long term verification test,
referring to the conventional cable standards of IEC and JEC.
Shipping test
Long term verification test Referenced
Sample cable of 5 m
30 m cable
standard
1 Partial discharge test 310 kV-10min
310 kV-10min
Test
2 Critical current
measurement
3 Load-cycle
(Long-term
verification test)
4 Critical current
Dielectric loss
5 Impulse voltage
DC
± 1155 kV-3shots
DC
200 kV-1 month
3 kA ON/OFF
More than 20 cylcles
DC
JEC-3408
After long term test
±1155 kV-3shots
JEC-3408
6 Partial discharge test 310 kV-10min
310 kV-10min
7 Voltage test
320 kV(2U0) 15min
320 kV(2U0) 15min
IEC62067
6 Voltage test
400 kV(2.5U0)
30min
400 kV(2.5U0) 30min
IEC62067
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10
Long-term Characteristics (V-t)
Evaluation of the Long-term characteristics (V-t) of model cables with insulation
thicknesses of 1 mm
V-t of PDIE and breakdown at 0.3 MPa(abs.)
Long-term verification test
AC Voltage [kV/mm]
60
1
VtypeAC
V-t of AC breakdown stress, n=50
50
40
n (life time constant) =50
U0=160 kV
42.3 kV/mm
65 h
30
30 years  365days n
U0  (
)
30days
V-t of PDIE, n=80
275 kV
760h
0.3 MPa(abs)
Voltage
160 kV
200kV
term
30 years
30 days
20
-3
10
-2
10
10
-1
0
10
1
10
10
2
10
3
time [hour]
Life time constant of PDIE was 80. There was no degradation after the V-t of PDIE.
Life time constant of B.D. was 50. There was degradation after the V-t of B.D.
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11
Sample tests (1) Ic, Over-current test
Ic:
Generated Voltage [mV]
Ic was obtained as 6440A at 77.3 K,
almost agreed the sum of all the used YBCO tapes
Over-current test:
At 63.0 kArms for 0.6 s, which
was the worst situation in 275 kV
systems
Transformer
Ic=6440 A (@1µm/cm)
(Voltage tap distance: 1.5 m)
Short HTS cable
with a joint part
Current [A]
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No Ic degradation after
63.0kArms for 0.6sec
12
Sample tests (2) voltage withstand tests
Detection of the PD inception stress
40
5
Cryostat for voltage tests
20
4
3
0
2
sinals of CD-5
Voltage [kV]
1
0
-20
Applied Voltage [kV]
Sample cable
Singals of CD-5 [V]
LN2/ PP laminated paper
-40
Time [10 ms/div]
Model cable Voltage test
AC Voltage test
400kV 30min
Imp Voltage test
1155 kV
PD test
310 kV (no P.D.)
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The sample was PD free at AC 310 kV
for 10 minutes and withstood at AC 400
kV in LN2 under atmospheric pressure.
13
Joint construction and Transportation
Cable joint
Terminal
HTS Cable
Shenyang
Japan
Dalian
China
After Vs. Before
Chiba,
Yokohama
Comparison result:
Visual confirmation There was no trouble
during the transportation.
Acceleration
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14
System construction (1)
Transformer
Testing sites
Terminal
XLPE cables for current carrying
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15
System construction (2)
Cooling system
安全弁
安全弁
安全弁
Monitoring
安全弁
安全弁
LN2 circulating in the closed loop,
No cooler.
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16
System construction (3)
Finished in October 2012
Transformer
Terminal
Joint
Cooling
system
monitoring
Cooling
system house
PD test Voltage
monitor controller
Current
controller
Cold Evaporator
Control room
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17
System construction
AC Transformer
Cooling
system
house
Joint
Joint & Termination
30 m HTS Cable
18
Results of Verification test (1)
Before long-term test
Ic: 77.3K
AC current test:
3 kArms
Conductor Current
Shield Current
Conductor layer:
6800 A
Shield layer:
7000 A
Current [A]
4000
2000
0
-2000
-4000
0
10
20
30
40
50x10
Time [s]
Withstand voltage test :
No PD(partial discharge ) at
AC 310 kV for 10 minutes
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The rate of shield current to conductor
current is about 75%, which is due to 13
m long of the normal conduction part in
the shield circuit according to the results
of numerical calculation. The inductance
of normal conductor is dominant. The
shield rate of only HTS cable is 98.6%
19
-3
Results of Verification test (2)
Long-term test
(11/18~12/20)
Successfully conducted
Operation
Temperature
72 K
Cooling
capacity
>3 kW
Voltage
200 kV
Current
3 kA
Cycle
>20 (8h ON, 16h OFF)
Term
1 month
200 kV- 1 month:
Determined by assuming
insulation degradation in 30
years
Voltage
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Current
20
Results of Verification test (3)
After long-term test
PD test:
No-PD was observed at
AC 310 kV for 10 minutes
Suggesting the superior reliability of this
HTS cable system even for 30 years.
Ic: No degradation
AC loss: 0.19 W/m
(measured by the calorimetric method)
Dielectric loss: 0.44 W/m at the operating voltage of 160 kV, which is
almost 25% lower than the designed value of 0.60 W/m
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21
Summary
275kV-3kA HTS cable was designed and fabricated:
・HTS Cable outer diameter 150 mm
・Ic 6440 A at 77.3 K of the conduction layers of 1.5 m long part
・PD-free at 310 kV and No BD at 400 kV in LN2 under atmospheric pressure
・No Ic degradation after the over-current of 63.0 kArms for 0.6 s
Construction of demonstration system was completed:
・Included the 30 m long HTS cable, two terminals, a cable joint and a cooling
system
Verification test :
・Ic of HTS conductor and HTS shield were 6800 A and 7000 A, respectively
・Long-term verification test was successfully conducted
・No-PD and No-Ic degradation after the long-term verification test
These results show a success in the development of 275kV-3kA
HTS cable with the world's highest voltage and largest capacity
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22