Dr. Joachim Bock Nexans SuperConductors D-50351 Huerth [e-mail]

1
Design, manufacturing and testing of robust HTS
elements based on BSCCO 2212 bifilar coils for
use in a 10-MVA fault current limiter 0
- Problem and Motivation 1 - Principle 2
- Application Cases 3 - German Project 10 kV /
10 MVA 4 - Conclusions / Benefits
Dr. Joachim BockNexans SuperConductorsD-50351
Huerthjoachim.bock_at_nexans.com
2
Problem and Motivation

• Growing demand for electrical energy and
  deregulation
• more through-wiring and transfer
• more grid couplings
• Increase of Renewable Energy Sources (RES) and
  utility restructuring Distributed Generation
  (DG) emergence
• Integration of low loss low impedance HTS
  cables in existing networks

Increased risk for short circuit currents
additional grid components over-dimensioning of
grid components
3
Principle of superconducting Fault Current
Limiting

• Intrinsic
• needs no trigger-signal
• fail safe
• Fast
• limitation already in the first front of the
  current
• Smooth
• avoids over-voltages
• Self-recovering
• after short duration ready for the next event
• Low impedance during normal operation
• no problems with reactive power
• no voltage drop

4
Application case Embedded Generation
New generation facilities increase short circuit
power enabling of direct feeding supply
5
Application case 110 kV grid coupling
Better use of existing grids less consumption of
landscape!
6
German BMBF-Project Curl 10 Partners Roles AC
CEL Instruments GmbH system development,
projectleader ACCESS e.V. simulation Adelwitz
GmbH material development YBCO Nexans
SuperConductors GmbH material development MCP
BSCCO 2212 EUS GmbH electrical net simulation FZ
Karlsruhe characterization, tests E.ON specific
ation RWE Energie AG demonstrator
test VDI-Phys. Technologiezentrum project sponsor
Objectives of Curl 10 Operation current 600
A Voltage (3 phases) 10 kV Power (3
phases) 10 MVA Limitation time 40 ms Max.
allowed peak current 8.75 kA (5 ms)
BSCCO 2212, Nexans
Two material options
YBCO, Adelwitz
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Melt Cast Processed BSCCO 2212 Bulk Parts for
direct system integration

• Nexans Bulk Parts are
• Inorganic ceramics (Bi-Sr-Ca-Cu-O)
• Available in a large variety of shapes and sizes
• Ready for assembling in electrical devices,
  system components or magnets

Annealing at 750 - 840C

• Characteristics
• rigid el. conductors
• easy machining
• high current carrying capacities
• (100A - 12kA)
• low thermal conductivity

Melt in rotating mould
Form parts from NSC being used in commercially
available industrial magnet systems
8
Todays Use of HTS Bulk Materials
Nexans Current Leads enabled first application of
HTS in electrical engineering
Oxford (dry magnet)
Bi-2212 for commercial use in current leads since
1995
ACCEL (SMES-system)
General Atomics (Current Controller)
IGC (SMES-system)
Fuji Electric (SMES-system)
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Development of HTS elements for FCL
first time (92001) successful quench test at
full HTS-element (540cm)
MCP Bi-2212 bifilar coil, 540cm
Solder
Shunt
Ic 800 A Jc 3500 A/cm²
HTS
current
hot spot
10
MCP BSCCO-2212 limitation behaviour at T 77K
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Three module short-circuit test Test at FGH
Engineering Test facility
symmetrical
asymmetrical
Fault current of 10 kA (18.8 kA) reduced to 6.6
kA (7.7 kA) Voltage 650 VRMS Current 600
ARMS Fault limitation 40 ms RT-resistance 360
mW Electrical field 0.56 V/cm ip/In 9
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Project status

• Only Nexans MCP BSCCO-2212 bifilar coils have
  reached all project specifications (competitor
  material failed)
• Successful short-circuit test of three bifilar
  coils (400 kVA model)
• A high resistive metallic shunt was successfully
  integrated
• Important Milestones of BMBF project CURL10
• - 1999 - Feasibility demonstrated
• - 2000 - Successful test of small samples MCP
  BSCCO-2212
• - 2001 - Successful test of BSCCO bifilar coil
• - 2002 - Successful 0.4 MVA test (Three BSCCO
  bifilar coils)
• 2003 - 1 MVA test, including chopped lightning
  impulse test (75 kV)
• 2003 - 10 MVA prototype test, field test

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10 kV / 10 MVA FCL Demonstrator
Application in busbar coupling Voltage 10
kV Current 600 A Fault limitation 60 ms
HTS-element for an FCL
Cryostat for 3 phases
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Benefits of superconducting FCLs

• cost reduction for substations and equipment
  due
• to lower short-circuit currents
• withstand to short-circuit currents in older
• substations (e.g. substation extension)
• longer lifetime of substations and equipment
• less damage at the short-circuit location
• high degree of intermeshing
• accommodation of new generation facilities
• increase of system reliability and integrity

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