System Studies on interaction of HTS cables with power grids
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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.
![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](https://image.slidesharecdn.com/irinamelnik-alliander-180305110354/85/System-Studies-on-interaction-of-HTS-cables-with-power-grids-6-320.jpg)
System Studies on interaction of HTS cables with power grids
- 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.