Alex Geschiere

1
Superconducting cables A breakthrough in
development

• Alex Geschiere
• Liandon member of Alliander

Alex Geschiere Netherlands Session 1 1256
2
Triax cable
Alex Geschiere Netherlands Session 1 Paper
1256
3
Cryostat design
Stainless steel inner tube Vacuum insulation
with multy layer insulation (MLI) Stainless
steel outer tube
Vacuum sealed for life. Residual gasses will be
absorbed by getter material
Alex Geschiere Netherlands Session 1 Paper
1256
4
Smart electrical behaviour
high Z
high Z
very low Z
very low Z
Alex Geschiere Netherlands Session 1 Paper
1256
5
Temperature profile
Challenge Limit the difference between maximum
and minimum temperature in long length cables
Alex Geschiere Netherlands Session 1 Paper
1256
6
Challenge Fault Current Limiting
high Z
High impedance at
High impedance
increasing current
Limiting of short circuit currents
Limiting of short circuit
Challenge Resistive limiting will cause a
significant amount of additional heat. Optimize
heat management during faults.
Alex Geschiere Netherlands Session 1 Paper
1256
7
Breakthrough in cryostat design
Heat leakage from 1.5 W/m to 0.5 W/m

• Reduced heat leakage in cryostat
• - optimize MLI and spacers
• - mix of straight/rigid sections and
  corrugated/flexible sections

Alex Geschiere Netherlands Session 1 Paper
1256
8
Low friction design
Low friction of Nitrogen mass flow
Test of a 45 m low friction cryostat. A mass flow
of 0.3 kg/s resulted in a pressure drop of only 5
mbar.
Alex Geschiere Netherlands Session 1 Paper
1256
9
Reduced AC losses
AC losses from 1.5 W/m/phase to 0.2 W/m/phase at
3000 Amps

• Reduction of gaps between tapes
• Narrow HTS tapes will fit the conductor shape
  better
• Special low loss 2G-tapes

Alex Geschiere Netherlands Session 1 Paper
1256
10
Test of reduced AC losses
Result form test AC losses at 3000 Amps of 0.11
W/m/phase (goal 0.2 W/m/phase)
Test of three different constructions/tape
designs. Huge impact on AC losses.
Alex Geschiere Netherlands Session 1 Paper
1256
11

• Significant improvement in development of HTS
  cables possible in a two years development
  program.
• Results are proved by several tests.
• alex.geschiere_at_alliander.com

Alex Geschiere Netherlands Session 1 Paper
1256