This document discusses the potential for using superconducting cables in power grids. It notes several challenges with current systems, including limited capacity and space. Superconducting cables could help address these issues by allowing higher power transmission at lower voltage levels with less infrastructure. The document outlines a study comparing the performance of superconducting cables to traditional copper cables. The results found that superconducting cables reduced losses, voltage fluctuations, and fault currents. They also decreased loading on parallel lines. The document concludes that superconducting cables have advantages like increased capacity and power transmission efficiency. They could help upgrade grids in a way that reduces costs, losses, and environmental impacts.

1. ENERGY CONNECTS
System Studies on
integration of
Superconducting cables
in power grids
Alex Geschiere
Maarten van Riet
Irina Melnik

2. ENERGY CONNECTS
Challenges:
 Capacity
 Short circuit currents
 Voltage fluctuations
 Reactive power
 Limited space
Energy transition and
economic welfare

3. ENERGY CONNECTS
New technologies are needed
HV grid
MV grid
LV grid
➢European back bone
➢Off-shore infrastructure
➢HVDC
➢Smart grids
➢IT
Superconducting
cables
Superconducting
cables

4. ENERGY CONNECTS
Superconductivity – the future
for the Netherlands
 Same or even higher power transmission at lower voltage level
 150 kV superconducting cables can become the workhorse of the
Netherlands
 Reduced number of substations
 Less complex to find a site for power facilities
 Reduction of cost for buying land & No additional construction costs
 Underground. No heating / cooling of the soil.
 CO2- emission reduction
Extremely low AC losses and stable voltage profile
No need for transferring to high voltage levels
to be able to transport more power

5. ENERGY CONNECTS
Cooperation of Alliander, Ultera and TU Delft
6 km 50 kV FCL HTS cable system in the Netherlands
R&D program of Alliander –
a push for the HTS technology
CryostatFormer
Phase 2 HTS Phase 3 HTS
Dielectric Dielectric Dielectric
Phase 1 HTS Copper Neutral
LN
LN
CryostatFormerFormer
Phase 2 HTSPhase 2 HTS Phase 3 HTSPhase 3 HTS
Dielectric Dielectric DielectricDielectricDielectric DielectricDielectric DielectricDielectric
Phase 1 HTSPhase 1 HTS Copper NeutralCopper Neutral
LNLN
LNLN

6. ENERGY CONNECTS
 Challenge: limiting the difference between
maximum and minimum temperature in
long cables
 Challenge: cooling stations only at the ends of the cable
L [m]
T[K]
Go
Return
Tmax
Aim: long length HTS cable
with FCL property


   
  
 
GO
RETURN
GO
RETURN
§ Long length cables
§ Cooling systems integrated in substations
§ Low maintenance


   
  
 
GO
RETURN
GO
RETURN
§ Long length cables
§ Cooling systems integrated in substations
§ Low maintenance

7. ENERGY CONNECTS
Measured record at 77 K:
AC losses: 0.11 W/m at 3 kA rms
Achieved: reduced AC-losses
 An optimal angle of the conductor layers
 Minimized gaps between the HTS tapes
 Narrow HTS tapes

8. ENERGY CONNECTS
Record:
Cryostat heat leak
0.5 W/m
Achieved:
Improved cryostat design
 Improved cryostat insulation
 Design for low friction
Measured record: pressure loss is only
5 mbar in the test setup

9. ENERGY CONNECTS
Long length FCL HTS cable
is possible!
The fault current is
limited to the range of
10-16 kApk!
 FCL modelling
 Simulated temperature of a 6 km HTS cable
Temperature profile is
sufficiently stable

10. ENERGY CONNECTS
Very low impedance of superconducting cables
 Reduced loading on parallel lines and equipment
 Reduced voltage fluctuations
 Low energy losses
Advantageous behavior of HTS
cables in power grids
Study case: Transmission of 750 MVA at 150 kV
150 kV HTS 3xsingle phase cable
I nom 3000 A
AC loss 0,15 kW/km/phase
Cryostat loss 3 x 0,5 kW/km
Efficiency of coolers 1:15
Termination
Loss 1 kW

11. ENERGY CONNECTS
150 kV
750 MVA
21
150 kV
150 kV
3 x XLPE cable
3 x 250 MVA
750 MVA
21
150 kV
750 MVA
150 kV
HTS cable
780 MVA
21
150 kV
Tot. loss (MWh)
14522
30067
46962
9851
29714
19745
6861
4662
2462
0
10000
20000
30000
40000
50000
10 20 30 km
3 x OHL
3 Pow er cables
HTS
ΔU (kV)
2,38
5,09
8,18
1,01
1,93
2,77
0,44 0,610,24
0,00
2,25
4,50
6,75
9,00
10 20 30 km
3 x OHL
3 Pow er cables
HTS
3 x OHL vs 3 x XLPE HTS cablevs
3 x OHL
3 x 250 MVA
Transmission of 750 MVA
a) Variant without redundancy (n-0)

12. ENERGY CONNECTS
4 x OHL
Transmission of 750 MVA
b) Variant with redundancy (n-1)
vs
4 x OHL
4 x 250 MVA
750 MVAI = 25 %
I = 25 %
I = 25 %
I = 25 %150 kV
2
150 kV
1
I = 17 %
3 x OHL
3 x 250 MVA
750 MVA
150 kV
2
150 kV
1
HTS cable
780 MVA
I = 83 %
ΔU (kV)
1,76
3,68
0,22 0,41 0,57
5,79
0,0
1,5
3,0
4,5
6,0
10 20 30 km
4 x OHL
HTS + 3xOHL
HTS cable parallel to 3 x OHL
Tot. loss (MWh)
22129
10801
34099
2781
5297 7808
0
7000
14000
21000
28000
35000
10 20 30 km
4 x OHL
HTS + 3xOHL

13. ENERGY CONNECTS
Transmission of 750 MVA
c) Variant with redundancy (n-1)
4 x XLPE cable
4 x 250 MVA
750 MVAI = 25 %
I = 25 %
I = 25 %
I = 25 %150 kV
2
150 kV
1
I = 39 %
3 x XLPE cable
3 x 250 MVA
750 MVA
150 kV
2
150 kV
1
HTS cable
780 MVA
I = 61 %
Tot. loss (MWh)
7337
3840
14622
21908
7386
10918
0
5000
10000
15000
20000
25000
10 20 30 km
4 Pow er cables
HTS+3xPow er cable
ΔU (kV)
0,74
0,23
0,45
1,37
1,91
0,38
0,0
0,5
1,0
1,5
2,0
10 20 30 km
4 Pow er cables
HTS+3xPow er cable
4 x XLPE vs HTS cable parallel to 3 x XLPE

14. ENERGY CONNECTS
Transmission of 750 MVA
d) Variant with redundancy (n-1)
4 x XLPE cable
4 x 250 MVA
750 MVA
150 kV
2
150 kV
1
150 kV
4 x OHL
4 x 250 MVA
750 MVA
2
150 kV
1
150 kV
2 x HTS cable
2x 780 MVA
750 MVA21
150 kV
Tot. loss (MWh)
10801
7337
14622
21908
12694
34099
22129
8638
4582
0,0
7000,0
14000,0
21000,0
28000,0
35000,0
10 20 30 km
4 x OHL
4x XLPE
2 x HTS
ΔU (kV)
1,76
0,74
1,37
1,91
0,19
5,79
3,68
0,170,11
0,0
2,0
4,0
6,0
10 20 30 km
4 x OHL
4x XLPE
2 x HTS
4 x OHL vs 4 x XLPE 2 x HTSvs

15. ENERGY CONNECTS
Conclusions from the study case
 The performed studies demonstrate a good parallel behavior of superconducting cables in
electrical grids.
 By parallel connection of an HTS cable to conventional cables or lines most of the load
flows through the superconducting cable, it allows:
– To unload existent circuits and to improve the voltage grid performance
– To decrease drastically the total energy losses.

16. ENERGY CONNECTS
Fault current limiting (FCL)
 Low energy losses
 Stable voltage profile
 Low impedance
 Short circuit currents
limiting during faults
 High impedance
0
Super -
conductivity
Normal
Ic Current I
Resistance R
0
Super -
conductivity
Normal
conductivity
Ic
Critical current

17. ENERGY CONNECTS
FCL simulations
(f ile sc_inif inite_grid_zonder_f cl.pl4; x-v ar t) c:X0002A-X0013A
0,00 0,05 0,10 0,15 0,20 0,25
-10
-5
0
5
10
15
*103
13,67 kA
(f ile sc_inif inite_grid.pl4; x-v ar t) c:X0005A-X0017A
0,00 0,05 0,10 0,15 0,20 0,25
-10
-5
0
5
10
15
*103
7,66 kA
Grid
XLPE cable
Ik peak
Grid
HTS cable
Ik peak
Ikpeak,kA
Ikpeak,kA
After one
cycle: 6,7 kA

18. ENERGY CONNECTS
Conclusions
 Advantages in using the HTS cable technology :
➢ Greatly increased power transmission capacity. Same or even higher power
transmission at lower voltage level
➢ Reduced loading on parallel lines and equipment
➢ Reduced voltage fluctuations
➢ Less reactive power production
➢ Low energy losses
➢ Fault current limiting
 As the AC losses of the HTS cable are very low, the cryostat losses and the termination
losses together with the cooling efficiency determine the total losses in the HTS cable
system.
 Transport of low amounts of power to short distances with HTS cables has a lower
efficiency. A considerable reduction of power losses can be achieved by using of HTS
cables for transport of sizeable power load.

19. ENERGY CONNECTS
Questions?