Superconducting fault current limiter to enable grid integration of wind power

The project focuses on the design of superconducting fault current limiter (SFCL) using second generation high-temperature superconductors (HTS). The proposed application of SFCL is to limit the ever-increasing fault current level of the grid network due to the increasing capacity of newly integrated renewable energy, especially wind power. Compared to exiting technology, e.g. SFCL using 1st generation HTS, the proposed SFCL has the advantage of quick recovery and low AC loss, which is enabled by thorough understanding of the underlying HTS physics.

The project has three phases. The initial physics study focuses on the quench development and propagation of HTS which is closely related to the performance of SFCL. Experimental and numerical methods will be employed in the study to explore how HTS reacts to applied currents which are higher than its critical current. The second phase focuses on the design of SFCL, optimized geometries will be identified, and the critical current and ac loss of the designs will be estimated by the modeling. The third phase is the integration simulation platform of grid system study with wind power, considering the real time reaction of SFCL. This simulation platform will serve as a strong tool to evaluate the SFCL performance under various system fault conditions.

1.Knowledge and people
The knowledge of HTS physics we learn from this project, especially the quench mechanism, will pave the way of future application of HTS. The knowledge will be delivered to both academic and industrial societies by means of project collaboration, article publishing, and conference presentations. We already have good publication records and impacts on journals of both applied physics and superconductivity fields (Applied physics letters, journal of applied physics, superconductivity technology and science, IEEE applied superconductivity), future impacts will be expanded to journals of energy (Energy, IEEE Sustainable energy). It is not certain that at this stage whether the project can lead to patents about SFCL. However, efforts will be made towards this end.

One post-doctoral researchers, and several 4th year undergraduates will be involved in the project with various contribution. The multidisciplinary study is a good opportunity to practise creative thinking and broaden their horizons. A fault current limiter workshop is in plan, collaborating with experts from applied superconductivity, and electrical engineering. The workshop aims at postgraduate students from EU countries, who are interested in the exploration of renewable energy, smart grid, and applied superconductivity. The superconductivity group of University of Cambridge has successfully organized a numerical modeling workshop of HTS (a workshop series with 2012 in Barcelona ) in 2011, a renewable energy summer school in 2012 (both based on Magdalene college). Both of the events offer import experience for organizing future events.

2.society
The project is expected to have great society impacts. The success of the project will have strong international influence, because it deals with a world wide challenge. And by using cutting-edge technology to a solve world-wide challenge, the UK will demonstrate to the world, its determination and strength to play a leading role in renewable energy development. Although we cannot make decision for the policy maker about how much renewable power would be integrated into the grid in the coming years, one thing is for certain: the successful development of SFCL with high performance will pave the way for future grid with high penetration of wind power.

In terms of pathways, initially, we will use media to internationally broadcast the launch of new funded SFCL project in the UK. During the project, we will update the progress of the project, using the means of academic papers, industrial news, interviews, and conferences. In the final test stage, we will spread our testing results to major national grids, wind manufacturers, and HTS manufacturers around the world.



3.Economy
The potential beneficiaries in terms of economy will be the grid, wind power manufacturers, and HTS manufacturers. The installation of robust SFCL in the grid will save potential troubles for the grid companies: the old network and equipments may not need to upgrade in order to withstand increasing fault current level; the choice of locations for the wind farm would be more flexible. Commercialization of high-temperature superconductors is essential to promote the HTS industry, because the consumption of HTS conductors will drive down the price, which, in return, stimulates future application and commercialization. For wind turbine manufacturers, the solution of wind power integrating challenge will influence the policy of future wind penetration in an implicit way, and the grid operators will be more willing to accept wind power to the network.