July 2010
Table of Contents
Second-Generation (2G) Wire Development
Los Alamos National Laboratory
DEPARTMENT OF ENERGY’S NATIONAL LABS LEAD COLLABORATIONS WITH INDUSTRY TO FURTHER TECHNOLOGY IN HTS APPLICATIONS
High-Temperature Superconductivity (HTS) will enhance the United States Electrical Power Grid by increasing grid reliability and security efficient power interconnections with high capacity. Superconducting fault current limiters will create a more stable electrical grid because they do not add impedance to the circuit during normal operations. HTS also reduces right-of-way requirements while minimizing environmental impacts.
Energy Secretary Steven Chu said, “ In order to meet President Obama’s ambitious energy goals, we must modernize the nation’s electrical grid to improve the transmission, storage, and reliability of clean energy across the country and help to move renewable energy from the places it can be produced to the places it can be used. By increasing transmission capacity and operators’ ability to control the movement of electricity, high-temperature superconductivity will help reduce electricity losses and save energy nationally.”
On April 26, 2010, the Department of Energy (DOE) released its 2009 National Electric Transmission Congestion Study. The study assessed transmission congestion and constraints within the Eastern and Western Interconnection and identified areas that were experiencing congestion-related problems. Congestion occurs when the flow of electricity from one point to another does not reach the necessary levels. HTS applications are designed to control power flow, which would alleviate grid congestion.
The DOE Office of Electricity and Delivery Energy Reliability’s Advanced Cables and Conductors Program and the National Labs work in partnership with industry to develop HTS wire and applications. Their collaborations in research and development are leading efforts to commercialize HTS electric power applications in the United States. This newsletter highlights selected collaborative efforts of DOE’s National Labs and industry that develop HTS applications in the areas of wire development, fault current limiters, and transformers.
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SECOND-GENERATION (2G) WIRE DEVELOPMENT
Collaborations in 2G Wire Development
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The Wire Development Group (WDG) is a multi-institutional collaboration focused on advancing the materials science of second-generation (2G) high temperature superconductor wires for energy and magnet applications in the U.S. and international markets. This group includes Los Alamos National Laboratory, Argonne National Laboratory, Oak Ridge National Laboratory, Florida State University, Industrial Research Limited, and American Superconductor Corporation (AMSC). The advancements in understanding and performance enhancements resulting from the WDG research on 2G HTS wire have been critical factors in the development of RABiTS and Metal Organic Deposition (MOD) processes as the performance- leading, low-cost technology for commercial 2Gwire. WDG also focuses on advancing the performance of YBCO films, characterizing pinning microstructures in MOD-based YBCO films and characterizing current limiting mechanisms in MOD-YBCO/RABiTS wires. WDG has demonstrated single-coat YBCO film with an lc of 450 A/cm-w, detailed characterization of the nucleation and growth of MOD-YBCO films, characterization of nanoparticle pinning centers in MOD-YBCO, and examination of current limiting mechanisms. It is also currently working on advancing the fundamental materials science of high-temperature superconductors, specifically mechanisms for enhancing current transport and vortex pinning in thick YBCO films. WDG’s goal is to overcome barriers and enhance the performance of RABiTS-based, 2G wire, commercial applications. |
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OAK RIDGE NATIONAL LABORATORY
Development of RABiTS- Based 2G Wires
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Oak Ridge National Laboratory (ORNL) and American Superconductor Corporation are collaborating to establish a low-cost, industrial manufacturing capability for 2G HTS wire based on the wide-strip MOD-YBCO/RABiTS technology. This collaborative project focuses specifically on developing a commercial HTS wire required for the DOE mission of developing transformational electric power equipment, such as cables, fault current limiters, and transformers based on HTS technology. This project targets near-term improvements to AMSC’s current 2G wire manufacturing process affecting yield and uniformity and long-term development of new materials and processes impacting future HTS wire performance and manufacturing cost. |
The ORNL-AMSC CRADA combines the expertise in the RABiTS template technology and unique characterization capabilities at ORNL with the process development and manufacturing expertise at AMSC to help establish an industrial manufacturing line for 2G HTS wire based on the RABiTS/MOD-YBCO technology. The close collaboration between ORNL and AMSC scientists, combined with the availability of unique resources at ORNL, enables the project team to explore a variety of potential technologies and new materials and to rapidly transform the most promising ideas into practical solutions that can be implemented in AMSC’s 2G wire manufacturing process.
ORNL scientists work closely with the AMSC R&D team to develop long-term improvements to the RABiTS technology and to assist in the scale up and optimization of AMSC’s 2G manufacturing line. This on-going collaboration has been extremely valuable in developing AMSC’s wide-web manufacturing process and addressing technical issues encountered during the initial operation and qualification of AMSC’s 2G manufacturing line. The technical contributions have been key to resolving template scale-up issues impacting both performance and yield. In addition, the collaboration has focused on the development of new materials and processes for the RABiTS technology which will impact the long-term performance and cost of 2G HTS wire produced in AMSC’s wide-web manufacturing process.
Development of MOCVD-based, IBAD 2G Wires
 Coil of 2G Wire |
Oak Ridge National Laboratory and SuperPower, Inc. work together to develop high-performance IBAD-MOCVD-based 2G wires for the commercial application of HTS technology. The approach is to carry out R&D support improve understanding of the fundamental properties of the IBAD-MgO templates as well as MOCVD-REBCO to enable manufacturing of robust and high-performance 2G wires. This understanding is critical to the development of a reliable, long-length manufacturing process. This project directly impacts the DOE program goal of developing prototype wire achieving 1,000,000 Amps of length-critical current (A-m) for second generation wire and producing a high-temperature superconducting coil that operates in applied magnetic fields up to 5 Tesla at 65 K for HTS applications. In short, close collaboration and interaction between ORNL and SuperPower have resulted in significant advancement in process understanding and development of a reliable manufacturing process at SuperPower. |
Coated Conductor Design for HTS applications
The goal of this research is to provide application-relevant information on the impact of conductor design in YBCO-coated conductors to wire manufacturers and device manufacturers with an emphasis on electrical power applications such as cables, fault current limiters, transformers, and motors. Strategic research on long-length, single-coated conductor prototypes and YBCO prototype devices has been directed toward providing benefits and tradeoffs in the technical areas of AC loss, conductor stability, and splice joints that allow effective utilization of coated conductors by device manufacturers. This research has shown the interactions between these technical areas that optimize conductor design for a given application and determine the extent that new conductor concepts translate to device level geometries.
This project involves collaboration across several different industrial and research organizations; collaborators include: AMSC, SuperPower, Southwire, Waukesha Electric, Los Alamos National Laboratory, NIST-Boulder, University of Houston, and Florida State University.
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LOS ALAMOS NATIONAL LABORATORY
Reactive Co-Evaporation on IBAD
The collaboration between Los Alamos National Laboratory (LANL) and Superconductor Technologies, Inc. (STI) is expected to assist the company in the development of high-performance and low-cost HTS 2G wire for power applications. This technology is based on LANL textured templates produced by ion-beam assisted deposition (IBAD) of bi-axially textured MgO films on high-strength, non-magnetic alloy substrates and reactive co-evaporation (RCE) of highly aligned and engineered YBCO films. This CRADA is intended to advance research that continually results in a more robust template technology that will simplify the processing and reduce cost. Furthermore, advances are expected in HTS films to engineer the conductor to optimize high-current performance in a magnetic field and in applied AC fields.
The LANL-STI collaboration combines the expertise at LANL in IBAD and RCE with extensive process development and manufacturing experience at STI using the RCE process for HTS materials. Their combined capabilities enable them to explore new coated conductor architectures relatively quickly and continuously improve their processes.
CRADA: Detailed characterization of AMSC wire
Reel-to-Reel SDP system at Super Power (Superpower, Inc.) |
Los Alamos National Laboratory and American Superconductor Corporation are working, through a CRADA, to expand the materials science knowledge base for YBCO coated conductor technology, use this knowledge to engineer the performance of 2G wires, and develop the necessary understanding to assemble these wires into devices such as cables that will meet the increasingly demanding needs of the electric power grid. The fundamental knowledge and performance improvements resulting from research with 2G HTS wires have been critical factors in the development of the RABiTS and Metal Organic Deposition processes as a performance-leading, low-cost technology for commercial 2G wire, addressing electric power applications over a range of cryogenic temperatures and magnetic fields. The collaborative program assists AMSC in establishing practical, low-cost process paths for large volume production of high-performance superconducting wire. LANL works with AMSC on research tasks that address materials and wire issues spanning multiple length scales. LANL also provides AMSC with advanced measurements of AC losses in various wire and cable configurations, providing the basis for advanced conductor design for electric power grid applications. |
The LANL AMSC CRADA also works in partnership with the Wire Development Group to complete the materials science underlying MOD-based YBCO film development. The goal is to develop an HTS wire technology that enables world leadership in HTS wire production by a U.S. company. This partnership allows AMSC to access the expertise of the scientists and engineers of LANL while allowing LANL participants to interact with the leading scientists from the DOE national laboratories, universities, and IRL.
CRADA: Development and Multi-Scale Characterization of IBAD
The LANL and SuperPower, Inc. collaboration is focused on advancing the development of high temperature superconductor wires for energy-efficient applications in the U.S. and international marketplace. The technology is based on textured templates produced by ion-beam assisted deposition of bi-axially textured MgO films on high-strength, non-magnetic alloy substrates and metal-organic chemical vapor deposition (MOCVD) of high-performance YBCO films. The purpose of this CRADA is to provide a fundamental understanding of the properties and microstructures across all relevant length scales of the MOCVD YBCO films and wires produced at SuperPower. This CRADA is also intended to foster research that continually results in a more robust template technology that will simplify the processing, reduce costs, and increase production yields.
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ARGONNE NATIONAL LABORATORY (ANL)
Characterization of 2G MOD Conductor
AMSC reel-to-reel solution MOD |
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The ANL/AMSC CRADA research is carried out largely under the sponsorship of WDG, ensuring that research topics address AMSC’s highest priority concerns. Active collaborations with WDG partners provide critical interactions, enhancing the value of new discoveries that can impact other areas of research.
2G MOCVD Coated Conductor
Argonne National Laboratory and Superpower, Inc. are working together to improve the performance of their long-length 2G HTS wire through detailed characterizations and analyses that identify key factors influencing wire performance. The focal points for the studies are understanding the factors that lead to Ic dropouts in SP’s long-length production wire, identifying pathways for increasing the overall critical current performance of the MOCVD coated conductor, and elucidating the microstructural and chemical characteristics that contribute to enhanced flux-pinning in MOCVD-type REBCO films. Based on the insights gained from these studies, ANL recommends process modifications to improve properties and provide additional guidance through follow-up characterization. |
SuperPower’s “helix” growth process (Superpower, Inc) |
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SANDIA NATIONAL LABORATORY (SNL)
Sandia’s superconductivity program aims to commercialize and technology-transfer manufacturable, high-speed methods of coated conductor fabrication based on solution deposition technologies. In 2002, Sandia demonstrated the first all-solution route to a 1 MA/cm2 coated conductor, using a single composition solution-deposited buffer layer (SrTiO3 on NiW). Since then, Sandia has worked to increase the manufacturability of both the YBCO and buffer layer processes, and collaborated with industrial and national laboratory partners to enhance the research program. Currently, the process is being scaled up to produce 10m-1km lengths of YBCO-based superconducting wire for use in Zenergy Power Systems Inc.-designed utility fault current controllers, energy-efficient induction heaters, and compact green power (wind power, hydroelectric) applications. In addition, solution deposition planarization has been developed jointly between SNL and LANL, and the prototype systems exist both at LANL and Superpower.
FAULT CURRENT LIMITERS
American Superconductor
American Superconductor is addressing the development and in-grid testing of a three-phase high-voltage, 115-kilovolt fault current limiter, called a SuperLimiter™, by using second-generation wire. The SuperLimiter™ features a proprietary Siemens-developed, low-inductance coil technology that makes the fault current limiter invisible to the grid until it switches to a resistive state. The demonstration will occur at a location operated by team member Southern California Edison. The team also includes: Nexans (France), the University of Houston (Houston, TX), DOE’s Los Alamos National Laboratory (Los Alamos, NM), and Siemens AG (Germany).
Zenergy Power Inc.
Zenergy Power Inc. is working to design, build and test a saturable iron-core type of 2G HTS FCL that is a prototype for a commercial product suitable for operating in a typical 138 kV transmission grid substation. The prototype will demonstrate the performance parameters and provide the data necessary to subsequently design a commercial product. The test device will undergo long-term demonstration in the electric grid of an electric utility partner to ensure that the operational, maintenance, repair, and coordination issues associated with a commercial product are realistically assessed and accurately documented. As deliverables, Zenergy Power will design, build, test, and demonstrate HTS FCLs at sites in the electric grid at distribution voltage and at transmission voltage of at least 138 kV. The team also includes: DOE’s Los Alamos National Laboratory, American Electric Power, Southern California Edison, Inc., Zenergy Power GMbH, and Zenergy Power Pty Ltd.
TRANSFORMERS
Waukesha Electric Systems (WES) and Oak Ridge National Laboratory (ORNL) are demonstrating the technical and economic feasibility and benefits of HTS transformers in ratings of 10 MVA and above. The ultimate goal is to fabricate and test a pre-commercial prototype HTS transformer operating at transmission level voltages in the 138-kV class. Building on experience gained in a preceding Phase II Superconductivity Partnership Initiative (SPI) HTS transformer project, ORNL and WES are now teaming with SuperPower and Southern California Edison to develop a 28-MVA, 69-kV fault-current-limiting HTS transformer for the DOE Smart Grid Initiative. Funding for a three-year project to accomplish this has been approved by DOE. Important objectives are to optimize the conceptual design using second-generation YBCO conductor, and to provide increased simplicity, manufacturability, and reliability. To speed the addition of HTS transformers to WES's product line, the project team intends to use as much of WES's conventional transformer manufacturing technology as possible. The project supports DOE's mission to develop revolutionary power equipment using HTS wires. |
HTS Transformer |
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CONCLUSION
HTS cable and application technology is an important solution to the modernization of the national power grid. For example, HTS AC cable has the ability to carry three to five times the amount of power compared to its antiquated copper counterpart, making it an attractive alternative to relieve cable system congestion. Moreover, HTS DC cable may carry gigawatts of electricity over vast distances with minimum loss, making it extremely attractive for remote delivery of renewable energy. FCL’s can reduce fault currents during faults to levels not exceeding three to five times the steady state current, protecting and extending the life of transformers and associated utility equipment. Lastly, HTS transformers convert generation-level voltage to transmission-level voltage, which reduces the amount of energy lost in the transmission of power over long distances. Working together, these power devices will enable the Clean Economy as well as interconnectivity and reconfigurability of the Smart Grid. In an effort to facilitate the research and further development of HTS applications, DOE and the National Labs are partnering with industry leaders. Their combined goal is to ultimately lead to the commercialization of HTS applications.
ABOUT THIS UPDATE
The High-Temperature "Superconductivity News Update" is compiled by Bob Lawrence & Associates, Inc. on behalf of the U.S. Department of Energy's superconductivity program and is issued periodically as events warrant.
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Ashley Thompson
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