FCL/B: An Integrated VSC-HVDC Fault Current Limiter/Breaker

Lead Research Organisation: University of Manchester
Department Name: Electrical and Electronic Engineering


Multi-terminal DC networks and meshed DC grids have been advocated by transmission utilities, industry and academe, as a potentially more cost effective means of integrating offshore renewable energy than point-to-point links. National Grid's Electricity Ten Year Statements and the European Network of Transmission System Operators for Electricity's Ten Year Network Development Plan as well as studies by The North Seas Countries' Offshore Grid Initiative all support this view.
To realize such HVDC networks, DC circuit breakers are necessary to isolate faulted DC sections. The unacceptable alternative would be to temporarily de-energise the whole DC network to then allow isolation of the faulted section. This is unacceptable because the resulting simultaneous loss of supply to the AC system would radically exceed onshore network design limits and would lead at least to severe disruption among consumers. For larger DC grids and power loss it would even cause widespread black-outs.
ABBs proactive HVDC circuit breaker comes close to the required efficiency and operational speed and indeed provides a solution for some cases. However it is fairly large, especially when the series 100mH inductor it requires to operate is considered. It is also appears to be targeted at a 5ms operating time, and commentators have indicated the need for protection against frequent faster events. The fastest such events have a rate of rise of current that requires breaking action in 2ms. A faster, smaller, cheaper solution is therefore still needed to enable offshore location of circuit breakers to allow offshore wind park integration.
This project will investigate novel designs integrating the circuit breaker with fault current limiter technology, which may thus be capable of achieving these size, speed and cost transformative targets.

Planned Impact

The principle impact of this project will be the thorough assessment of the capabilities and multi-physics limits of superconducting Fault Current Limiters and HVDC Circuit Breakers for VSC-HVDC systems. DC circuit breakers form a bottleneck in the development of HVDC offshore grids, and if suitable devices are not available, the construction of large integrated DC grids will not be possible and more expensive solutions will be required. This project's research will thus majorly shape the development of DC offshore networks. The research will accordingly influence investment decisions in future networks by transmission utilities and design decisions by manufacturers, as well as influencing grid code development and system regulation decisions.

The project is also expected to generate IP in the form of new DC circuit breaker/fault current limiter component inventions and designs. This will be protected and developed through the intellectual property management arm of the University of Manchester (UMIP) either in the form of licensing, or should sufficient novelty arise, as potentially a spin-out company in partnership with project sponsors.

The potential expenditure on offshore VSC-HVDC networks is up to £30billion in just the UK, and just in the foreseeable future. Savings of up to one third (Peter Jones, ABB) are possible for getting the system 'designed right.' Making the right network design decisions is important - this proposal aims to ensure that the appropriate research as regards DC protection is available to inform such decisions.
Description Large DC grids are being developed as a solution to integrate large amounts of low-carbon renewable energy into the power network, and to connect to other countries. As such networks develop, DC protection (DC breakers) will be required. This proposal investigates a new category of ultra-fast breaker and its components and use. Extensive new knowledge on innovating faster mechanical breakers, superconducting fault current limiter / breaker designs, powering such systems and their interaction with the remaining HVDC system has been generated. This has resulted in a large amount of papers and considerable interest from allied fields (e.g. marine systems).
Exploitation Route Manufacturers of HVDC equipment are all developing DC breaker technology and this first large scale grid requiring such breakers is due to be constructed in China in 2018 (Zhangbei). We are in discussion with manufacturers in electrical power networks and marine / aerospace on how to develop our findings further. However in the last 3 years a lack clarity on the development of the UK generation system arisen, meaning plans for large DC grids, and therefore the need for HVDC breakers, have become less urgent.
Sectors Energy

URL http://homeoffshore.org/index.php/related-projects/fclb-project/
Description The results of this project are of considerable interest to a Swedish HVDC breaker company (SciBreak) and they have expressed interest in the technology. However our partnership with their competitor (GE) has prevented further development of this beyond such results as are published.
First Year Of Impact 2017
Sector Energy
Impact Types Economic

Description GE 
Organisation Alstom
Department Alstom UK
Country United Kingdom 
Sector Private 
PI Contribution Reports and research relevant to company business.
Collaborator Contribution Technical advice, engineering time, case studies.
Impact None yet.
Start Year 2013
Description SSE 
Organisation Scottish and Southern Energy (SSE)
Country United Kingdom 
Sector Private 
PI Contribution Research advice on day-to-day and future technical aspects of SSE's business.
Collaborator Contribution Engineering time, advice and case studies.
Impact None at this point.
Start Year 2014
Description UNSW - Placement 
Organisation University of New South Wales
Country Australia 
Sector Academic/University 
PI Contribution We worked with Prof Pou's team at UNSW to trial out HVDC breaker ideas out on the Real Time Simulator and test interaction with the HVDC converter and the formulation of supervisory control. The PDRA (O Cwikowski) spent 3 months in their labs, and Prof Mike Barnes visited UNSW also and was in contact through regular Skype calls.
Collaborator Contribution Prof Pou and his colleagues provided technical guidance and access to their world-leading real-time simulation facility.
Impact This work was fully report in the paper O. Cwikowski, H. R. Wickramasinghe, G. Konstantinou, J. Pou, M. Barnes, R. Shuttleworth, Modular Multilevel Converter DC Fault Protection, IEEE Trans. Power Delivery, DOI: 10.1109/TPWRD.2017.2715833.
Start Year 2016
Description Keynote at the IEEE PEDS Conference in Sydney Australia 2015 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Keynote given at conference on research in this project.
Year(s) Of Engagement Activity 2015
Description Presentation to Canterbury University, Christchurch, New Zealand 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Professional Practitioners
Results and Impact Presentation to the Engineering Department at Canterbury.
Year(s) Of Engagement Activity 2015
Description Presentation to Cigre B4-72 Working group 
Form Of Engagement Activity A formal working group, expert panel or dialogue
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Description of research to study group on multiterminal grids comprising international academics and industrialists from the UK, Europe, N America, China and Brazil.
Year(s) Of Engagement Activity 2017
Description Presentation to the University of New South Wales, Australia on research 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Postgraduate students
Results and Impact Presentation to research group at UNSW.
Year(s) Of Engagement Activity 2015
Description VSC HVDC Newsletter 
Form Of Engagement Activity A magazine, newsletter or online publication
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact This is a newsletter which goes to industry, utility, academia and government providing monthly updates on VSC HVDC research.
Year(s) Of Engagement Activity 2014,2015,2016,2017