HTS Transformer and SFCL-Transformer
Overview | HTS Transformer Project | SFCL-Transformer Project
Transformers are an integral part of the electricity transmission and distribution network throughout the world. Energy is transmitted from substation to substation through transformers that either step up voltage (for long distance transmission) or step down voltage (for consumer use). In the U.S. there are approximately 140,000 medium-power transformers that are approaching 40 years of service – the end of their life. Within the coming generation, the vast majority of these conventional transformers will need to be replaced.
HTS Transformer offer numerous benefits:
- Greater efficiency – HTS transformers help reduce the amount of energy lost in the transmission of power over long distances to more than pay for initial capital cost of the device over its lifetime. This benefits the electricity consumer through lower costs from the reduction in losses due to the inefficiencies of conventional power transformers
- Smaller, lighter and quieter – HTS transformers occupy a smaller footprint than conventional transformers, enabling existing substations to increase distribution capability without expanding into limited or expensive real estate
- Ability to run above rated power without affecting transformer life - HTS-based transformers with operation at cryogenic temperatures completely avoid the thermal aging processes that ultimately destroy conventional transformers
- Liquid nitrogen cooling – HTS transformers do not require cooling oil like conventional transformers, thereby eliminating the possibility of oil fires and related environmental hazards and enable placement in an enclosed building or even a multi-story building in densely populated areas
- Flexibility in siting – smaller size and weight, and the capability to operate at over-capacity result in greater siting flexibility and potential lower transformer cost per unit power delivered, and more power per unit area in existing substations
- Economic advantages for utilities - Lower installation and total owning cost for each transformer
SFCL-Transformers offer additional benefits by integrating fault current limiting (FCL) capability into a medium-power utility transformer:
- Meaningful downstream protection for existing substation circuit breakers and other devices
- Reduction of prospective fault current due to network upgrades or the addition of new generation (including wind, solar and distributed generation) to a lower, safer level where the existing switchgear can still protect the grid
- Providing the necessary current limiting impedance during a fault, with essentially zero impedance during normal grid operation. SFCL transformers, therefore, have no negative impact on overall system performance.
Relevance: Demonstrating the SFCL Transformer in a utility substation brings many near and long-term benefits. The device is expected to lower power consumption through reduction of losses, increase the reliability of the nation’s grid, and through the demonstration of this device, speed commercial adoption by utility operators.
2010-2015 SFCL Transformer Project
The overall project objective is to design, develop, manufacture and install on a live grid utility host site a Smart Grid-compatible Superconducting Fault Current Limiting Transformer.
This project extends the earlier work on the development of both a 1 MVA and a 5 MVA, 25 kV / 4.2 kV HTS power transformer carried out in previous DOE Superconductivity Partnerships with Industry (SPI) and Superconductivity Programs for Electrical Systems (SPE) projects by the team including Waukesha Electric Systems, SuperPower, and Oak Ridge National Laboratory (ORNL). Additional project partners in this new DOE Smart Grid Demonstration Project include the Texas Center for Superconductivity at the University of Houston and Southern California Edison, the host utility for the device.
Program Duration: 2010-2015
- Waukesha Electric Systems – transformer design and fabrication, commercial product development
- SuperPower Inc. – 2G HTS wire production, FCL expertise
- University of Houston, TcSUH – 2G HTS wire design, FCL expertise
- Oak Ridge National Laboratory (ORNL) – cryogenics and application
- Southern California Edison (SCE) – host utility, general specifications, site preparation and field work, installation and commissioning
- $21.5M overall cost
- $10.7M from U.S. Department of Energy
SFCL Transformer Specifications:
- 28 MVA 3-phase FCL medium-power utility transformer (69 kV / 12.47 kV class)
- ~ 40% overload capability without loss of life
- Incorporating fault current limiting capability into the superconducting transformer without adding significant complexity or cost to the device
- To be installed within Southern California Edison’s Smart Grid substation in Irvine, CA in 2013
- First transformer to use significant amounts of the new second-generation (2G) (RE)BCO HTS wire
... the mark of excellence
1996-2002 HTS Transformer Projects
Development of the HTS Transformer began in 1996 under the DOE’s Superconductivity Partnerships with Industry (SPI) program. Waukesha Electric Systems partnered with Intermagnetics General Corporation (acquired by Royal Philips Electronics in 2006) in two program phases, both of which utilized BSCCO-based HTS, also known as 1G HTS:
- A 1 MVA prototype HTS transformer was designed and built by the team and successfully tested in 1998.
- A larger, 5/10 MVA system-level prototype transformer program was subsequently designed and built. Further development work has focused on the use of 2G HTS wire in the device.
Program Duration: 1996-2002
- Waukesha Electric Systems – transformer manufacturer
- Intermagnetics General Corporation/SuperPower Inc. – HTS wire and coil manufacturer
- Rochester Gas & Electric – utility end user
- Oak Ridge National Laboratory (ORNL) – supporting research
- Rensselaer Polytechnic Institute – supporting research
- $21.5M overall cost
- $10.7M from U.S. Department of Energy