ACCELERATED ELECTRICAL AND MECHANICAL AGEING TESTS … · 18-May-17 Accelerated Electrical and...
Transcript of ACCELERATED ELECTRICAL AND MECHANICAL AGEING TESTS … · 18-May-17 Accelerated Electrical and...
ACCELERATED ELECTRICAL AND MECHANICAL
AGEING TESTS OF HIGH TEMPERATURE LOW
SAG (HTLS) CONDUCTORS
Dominik Stengel, Richard Bardl (BAM)
Christian Kühnel, Steffen Großmann (TU Dresden)
Wilhelm Kiewitt (50Hertz)
27-April-2017
The idea
18-May-17 Accelerated Electrical and Mechanical Ageing Tests of HTLS Conductors 2
Expansion of transmission system
Uprating of transmission lines
HTLS conductors
Higher capacity due to higher rated temperature
- Lower sag (thermal expansion)
- Temperature resistant materials
Limited long-term experience!
Expansion of transmission system
Uprating of transmission lines
HTLS conductors
Higher capacity due to higher rated temperature
- Lower sag (thermal expansion)
- Temperature resistant materials
Material degradation? (RTS,electrical resistance, creep…)
Selected conductors
18-May-17 Accelerated Electrical and Mechanical Ageing Tests of HTLS Conductors 3
conductor Core material Outer layers Structure
ACSR Steel Hard drawn aluminum
ACCC,
ACPR
Polymer matrix
composite
Annealed or thermal aluminum
ACCR Metal matrix
composite
Thermal aluminum
GZTACSR
„Gap“
Steel Thermal aluminum
Also tested: ACSS, ZTACIR, TACSR
Conductor ageing
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Reality(50 years)
Laboratory(6 months)
Everyday stress, Tensile forcewind loads
Thermal and electrical Maximum rated and loads emergency temperature
Corrosion (temperature, not studiedenvironment)
Tensile force
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Applied tensile force = Static load + Cyclic load
Static load (Everyday stress)
- Calculated for an ideal single span of 413 m and 15.5 m sag
ca. 15 % RTS (depending on the conductor‘s specific
weight)
From wind velocity to tensile force
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Wind velocitiesin 50 years
According to EN 1991-1-4
(10 m height, wind zone 2,
rural terrain)
10 15 20 25
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freq
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cy i
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ann
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bab
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0 500 100010
15
20
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cumulative frequency for 50 years
vb i
n m
/s10 15 20 25
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vb in m/s
freq
uen
cy i
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0 y
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10 15 20 25
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bab
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y,
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0 500 100010
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20
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cumulative frequency for 50 years
vb i
n m
/s
From wind velocity to tensile force
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5 classes ofwind speeds
Wind velocities
in 50 years
10 15 20 25
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20
30
40
50
vb in m/s
freq
uen
cy i
n 5
0 y
ears
10 15 20 25
0.2
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annual
pro
bab
ilit
y,
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0 500 100010
15
20
25
cumulative frequency for 50 years
vb i
n m
/s
10 15 20 25
10
20
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40
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vb in m/s
freq
uenc
y in
50
year
s
10 15 20 25
0.2
0.4
0.6
0.8
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annu
al p
roba
bili
ty,
p
0 500 100010
15
20
25
cumulative frequency for 50 years
v b in
m/s
From wind velocity to tensile force
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Turbulent wind fieldbased on provisions
5 classes ofwind speeds
Wind velocities
in 50 years
10 15 20 25
10
20
30
40
50
vb in m/s
freq
uen
cy i
n 5
0 y
ears
10 15 20 25
0.2
0.4
0.6
0.8
1
annual
pro
bab
ilit
y,
p
0 500 100010
15
20
25
cumulative frequency for 50 years
vb i
n m
/s
10 15 20 25
10
20
30
40
50
vb in m/s
freq
uenc
y in
50
year
s
10 15 20 25
0.2
0.4
0.6
0.8
1
annu
al p
roba
bili
ty,
p
0 500 100010
15
20
25
cumulative frequency for 50 years
v b in
m/s
Generation of a 10
minutes wind field
From wind velocity to tensile force
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Tensile force on conductor based on
FE simulation
Validated FE-model for
existing overhead line in
Northern Germany
Turbulent wind field based on
provisions
5 classes ofwind speeds
Wind velocities
in 50 years
10 15 20 25
10
20
30
40
50
vb in m/s
freq
uen
cy i
n 5
0 y
ears
10 15 20 25
0.2
0.4
0.6
0.8
1
annual
pro
bab
ilit
y,
p
0 500 100010
15
20
25
cumulative frequency for 50 years
vb i
n m
/s
10 15 20 25
10
20
30
40
50
vb in m/s
freq
uenc
y in
50
year
s
10 15 20 25
0.2
0.4
0.6
0.8
1
annu
al p
roba
bili
ty,
p
0 500 100010
15
20
25
cumulative frequency for 50 years
v b in
m/s
From wind velocity to tensile force
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Turbulent wind field based on
provisions
Tensile force on conductor based on FE simulation
5 classes ofwind speeds
Wind velocities
in 50 years
- Equivalent harmonic
forces with defined
mean, amplitude and
number of cycles using
rainflow count
- Reduction to 3 cyclic
loads and amplitudes
using Palmgren-Miner
Defined cyclictensile force
10 15 20 25
10
20
30
40
50
vb in m/s
freq
uen
cy i
n 5
0 y
ears
10 15 20 25
0.2
0.4
0.6
0.8
1
annual
pro
bab
ilit
y,
p
0 500 100010
15
20
25
cumulative frequency for 50 years
vb i
n m
/s
10 15 20 25
10
20
30
40
50
vb in m/s
freq
uenc
y in
50
year
s
10 15 20 25
0.2
0.4
0.6
0.8
1
annu
al p
roba
bili
ty,
p
0 500 100010
15
20
25
cumulative frequency for 50 years
v b in
m/s
Cyclic loading for ACSS (RTS = 156 kN)
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Minimum load [kN] Maximum load [kN] Number of cycles
Static loading 24 24 Constant
Wind load 1 24 33 141,780
Wind load 2 29 37 3300
Wind load 3 33 41 30
x 150 days at 200 °C
Testing rack for artificial ageing
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- Test of 4 different conductor types simultaneously in two parallel lines
- Conductor length of approximately 20m
Testing rack in Ragow (Germany)
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Creep
Single wire
stress strain
Conductor stress strain
Self-damping
Ductility test on wires
Grease test
Electrical resistance
(TU Dresden)
Electrical and mechanical accessories
tests
Conductor tests
Test result: Tensile strength of aluminum
- Ageing 4000 h at 210 °C, 400 h at 240 °C
- ZTAL (AT3, aluminum-zirconium-alloy)
- Tensile strength decreased of 29 % after
ageing
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Sample Standard New AT3 Aged AT3
1 2.37 kN 2.58 kN 1.75 kN
2 2.37 kN 2.49 kN 1.73 kN
3 2.37 kN 2.36 kN 1.78 kN
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Summary
– Scientific development of an artificial ageing regime
– Successful implementation in a test stand
– Ageing of 8 different conductor technologies
– Extensive mechanical and electrical test program prior and after
ageing
– First test results show interesting ageing effects
– Overall results expected at the end of 2017