MTVN: Multi-Terminal VSC-HVDC Networks - Grid Control

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

Abstract

Reliable electricity supply forms a one of the basic requirements of modern 21st Century life. Sustaining this reliable supply is one of the key challenges for the coming decades. A solution is not straight-forward and will have many parts. Integrating offshore wind energy generation as cheaply as possible is one part. Linking our electricity transmission network to the generation and services of other European countries is another part. Reinforcing the onshore electricity network to cope with new power flows, is a further part.
Addressing these challenges requires an offshore electricity network, which is controlled to support our existing infrastructure. Such an offshore network disrupts far less of the onshore countryside and living environment than conventional onshore solutions. Enabling this necessary offshore network is the goal of this proposal. The technology needed to achieve such a solution is so-called Voltage-Source High-Voltage DC Transmission (VSC-HVDC): DC connections using converter stations with the latest state-of-the-art, high-voltage semiconductor power processing technology. Only such stations have the required flexibility, compactness offshore and ability to transmit power over long sub-sea cables. However our experience with such technology is limited to point-to-point systems. No small networks (so-called multi-terminal systems) have been built. No large networks (so-called DC grids) have been constructed. Very little research has been published into how to control such systems. There is a dearth of information on how to make large offshore networks 'work'. However many industrial and academic organizations have highlighted the substantial potential benefits in terms of reduced cost, improved reliability and greater functionality which could be offered by such DC offshore networks to our existing electricity infrastructure.
This project will undertake the research urgently required to assess the best way to control and mange such networks. Since telecommunications, controller architecture and control are intimately linked, research to assess and include the impact of these constraints will also be incorporated. Candidate networks will be formulated, analyzed and simulated using state-of-the-art models. These models will be improved to include the effects of distributed control and telecommunications effects/Quality of Service. New techniques will be developed that allow similar benefits to 'perfect' (idealized Master) control to be achieved with more realistic distributed hardware systems.
The transformative goals of this project are thus:
1. To establish how Master and Distributed Master controllers can improve VSC-HVDC-grid performance and offer robust and reliable services to AC onshore networks.
2. To investigate advanced controls, and effective exploitation of state-of-the-art and developing telecommunication technologies, to integrate this control with local station control and to overcome conventional operational speed limitations.
Better system understanding, models, and improved control will result. This in turn should allow the creation of a cheaper, more effective offshore network.

Planned Impact

The principle impact of this project will be the thorough assessment of the benefits accruing from multi-terminal control of large DC networks compared with traditional local only control. This will significantly inform multi-terminal design, investment decisions in future networks by transmission utilities and design decisions by manufacturers. It will also influence grid code development and system regulation decisions.

The project is also expected to generate IP in the form of new control algorithms and methodologies. 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 investigation of how such control can affect the robust operation of HVDC networks and AC networks, will significantly influence policy decisions in the UK, Europe and beyond as such HVDC connections are developed. The assessment of the degree to which gaming could take place, has a major impact on the markets and international cooperation treaties which need to be negotiated prior to the creation of such a combined market and network structure. This work is thus important and extremely timely.

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) as possible for getting the system 'designed right.' Making the right networks design decisions is important - this proposal aims to ensure that the appropriate research as regards high-level control and operation is available to inform such decisions.
 
Description The study of future DC transmission links is important since their use will increase substantially but their interaction with the existing AC network is not yet fully understood under a scenario where they become widespread. The project addressed a number of issues including high level control, telecommunications and the accuracy required in feedback sensing to achieve the control levels expected. A number of improved models have been developed and have been used to assess the interaction of future AC and DC systems. This will act as an important reference for when the UK comes to connect large offshore wind farms to shore using AC/DC connection, and to connect the UK to Europe using AC/DC electrical power links. The work is presently being used to inform discussion on future electrical power grids, for example through a VSC-HVDC Newsletter and participation in the Cigre B4-72 working group which has published a technical brochure on multi-terminal VSC-HVDC shortly.
Exploitation Route We are continuing to discuss this with our commercialisation team at the university and with our industrial partners. The models developed are being used extensively and extended further in the EPSRC project HOME Offshore (EP/P009743/1) which is applying them to predictive maintenance of offshore wind farms and connections to shore.
Sectors Energy

URL http://homeoffshore.org/index.php/related-projects/mtvn-project/
 
Description EPSRC - standard research
Amount £3,048,221 (GBP)
Funding ID EP/P009743/1 
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Academic/University
Country United Kingdom
Start 04/2017 
End 04/2020
 
Description HOME-Offshore: Holistic Operation and Maintenance for Energy from Offshore Wind Farms
Amount £3,048,221 (GBP)
Funding ID EP/P009743/1 
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Academic/University
Country United Kingdom
Start 04/2017 
End 04/2020
 
Description MTTE: Stability Assessment of Multi-infeed HVDC Systems
Amount £59,000 (GBP)
Organisation Scottish and Southern Energy (SSE) 
Sector Private
Country United Kingdom
Start 07/2016 
End 12/2016
 
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 TNEI 
Organisation TanSat (CarbonSat) mission
Country China 
Sector Public 
PI Contribution Reports adn technical know-how to day-to-day running of business.
Collaborator Contribution Technical advice and case studies.
Impact not at this point yet
Start Year 2014
 
Description Presentation 'Losses, Component Sizing and Modulation in VSC-HVDC' 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Postgraduate students
Results and Impact Presentation as part of the EES-UETP tutorial series in HVDC Technology and Applications this is a series of seminars over several days to educate new Europe Postgraduate students about HVDC.
Year(s) Of Engagement Activity 2014
 
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