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Projects: Projects for Investigator
Reference Number	NIA_NGET0045
Title	Multi-terminal VSC HVDC operation, control and ac system integration
Status	Completed
Energy Categories	Other Power and Storage Technologies(Electricity transmission and distribution) 100%;
Research Types	Applied Research and Development 100%
Science and Technology Fields	ENGINEERING AND TECHNOLOGY (Electrical and Electronic Engineering) 100%
UKERC Cross Cutting Characterisation	Not Cross-cutting 100%
Principal Investigator	Project Contact No email address given National Grid Electricity Transmission
Award Type	Network Innovation Allowance
Funding Source	Ofgem
Start Date	01 October 2011
End Date	01 June 2016
Duration	56 months
Total Grant Value	£531,000
Industrial Sectors	Power
Region	London
Programme	Network Innovation Allowance
Investigators	Principal Investigator	Project Contact , National Grid Electricity Transmission (100.000%)
Web Site	http://www.smarternetworks.org/project/NIA_NGET0045
Objectives	The objective of the project is to improve understanding of the problems of Voltage Sourced Converter (VSC) HVDC integration into the existing transmission system. The project aims to make progress in three related areas: 1. Multi-terminal VSC HVDC operation;2. AC/DC VSC HVDC interaction-controland3. AC/DC VSC HVDC interaction - detailed model (fast transients). These areas have been identified as requiring to be addressed as part of the risk managed introduction of the technology onto the transmission system. The project will deliver reports on the results of studies and a documented set of models for use in National Grid’s internal system studies. The work forms an essential step in being able to implement the technology on the transmission system. The project is likely to increase understanding of the issues associated with application of a multi-terminal VSC HVDC system on the GB transmission system. There is a high likelihood that such studies will allow application issues to be identified, better understood and enable their mitigation to be evaluated. This is success for the project.
Abstract	It was recognised in the report that due to planning constraints and environmental concerns, traditional methods of enhancing system capacity can be difficult to achieve and consideration was given to employing the latest technology, especially where this would yield additional economic and/or environmental benefits. One such technology potentially contributing to the achievement of the above aims is Voltage Sourced Converter (VSC) HVDC transmission. Furthermore, VSC HVDC is, in principle, well suited to multi-terminal applications which would allow optimised designs integrating onshore and offshore networks to be achieved and such solutions are under consideration for the GB transmission system. However, while the technology is believed to be achievable, National Grid has not previously implemented VSC HVDC on the GB transmission system and multi-terminal VSC HVDC has not previously been implemented anywhere. It is essential, therefore that an adequate understanding of the application issues be developed. In order to initiate work in this important and urgent area, it is proposed that National Grid fund three PhD students who are available to start work immediately at the University of Manchester. Each student would address one of the three areas indicated above. The work is complementary to the simulation of multi-terminal VSC HVDC system by means of real time digital simulator (RTDS) at the University of Birmingham which is the subject of a separate R&D proposal. The method that has been proposed for this project includes the following;1. MULTI - TERMINAL VSC HVDC OPERATION- Familiarisation with VSC HDVC and AC system modelling in DigSILENT. - Construction of a base case 40terminal generic VSC HVDC system in DigSILENT - hardware and structure- Investigation of multi-terminal HVDC and development of a series of multi-terminal scenarios; comparison of methods of ac and dc side control with DigSILENT simulation verification- Development of lead candidate scenarios into models - RMS AC system representation - detailed dc multi- terminal behaviour. Parameterisation and testing- First year PhD transfer report- Investigation of dc control parameterisation for quasi-steady-state operation - local terminal control and multi terminal system control. Development of droop line settings for terminal control over whole operating range- Fault study for power electronics system and system parameterisation - introduction of the associated non- linarites and the subsequent re-design of control algorithms and other system elements to be capable of dealing with them- Study and identification of key slower transient phenomena (both ac and dc side), severity assessment and impact on control- Robustness study identification of controller stability limits and key compensation requirements/controller modifications at both the local and multi-terminal levels- Develop and test a detailed, more fully parameterised case study for a multi-terminal HVDC system- Test the detailed case study system fully across the whole operating range of possible operational scenarios identified to help establish design and specification guidelines. 2. AC/DC HVDC INTERACTION - CONTROL- Familiarisation with VSC HVDC and system modelling in DigSILENT- Construction of base case VSC HVDC and generic AC network system in DigSILENT - hardware, structure and control- Scoping study - investigation of a range of probable future scenarios with different level of penetrationand technology mix of HVDC lines and series compensation of AC lines. Identification of key dynamics and fidelity of models required, identification of key studies to be performed. Justification of key scenarios to model. - Implementation of key scenarios and model verification in PSCAD/EMTCD to act as a base case comparison- First year PhD transfer report- Implementation of key scenarios and model verification in DigSILENT with PSCAD/EMTDC to act as a comparator- Investigation of transient control behaviour and parameterisation (RMS/EMT mode) for system in response to candidate scenarios. - Revised and more realistic system models; thorough testing of detailed fidelity scenarios against published/public performance of system components- Robustness and sensitivity study; identify potential for controller interactions (FACTS and SVC controllers and conventional, existing POD controllers, i.e. PSSs, series compensation) over pre-determined range of parameter variation and operating scenarios. Identify potential remedial actions required- Second year PhD transfer report- Identify minimum additional control requirements for each of probable scenarios. This could include required re-tuning of existing POD controllers (conventional PSSs) and/or application of supplementary WAMS based POD controllers applied at HVDC terminals. Illustrate effectiveness of each of the potential solutions on generic case studies. - Review of methodologies applied to carefully chosen limited set of particular case study/studies. 3. AC/DC HVDC INTERACTION - DETAILED MODEL- Familiarisation with VSC HVDC and AC system modelling in PSCAD- Construction of detailed VSC HVDC model in PSCAD - hardware, structure and control. Familiarisation with DigSILENT modelling- Identification of key system dynamics and fidelity of AC and DC component models required, identification of key studies to be performed. Justification of key scenarios to model- Implementation of key AC and DC component models in PSCAD and DigSILENT. This will include key primary plant components (power electronics and applicable control, transformers, cable transmission line, circuit- breaker, busbar, current and voltage transformers, filter banks). An assessment will be made of the level of fidelity required in the DigSILENT models to capture key dynamics. A PSCAD model set will be used as a detailed system model comparator. First year PhD transfer report. - Report writing and documentation for models- Detailed system model for local AC network model to allow candidate scenarios of AC/DC detailed interaction to be studied- Second year PhD transfer report- Scoping of investigation of detailed system interaction behaviour, including harmonics, switching transients, faults and detailed system electromagnetic interaction. Preliminary validation against published results. The goal is to define which models need further refinement and/or information and to undertake such refinement - Robustness and sensitivity study; identify potential for AC/DC component interactions over a range of parameter and operating scenarios. Identify remedial actions required- Identify minimal additional requirements for problems identified in robustness and sensitivity study that cannot be resolved by basic remedial actions (such as choosing a different rating or different controller gain). This could include the use of supplementary harmonic filters at HVDC terminals for example.Note : Project Documents may be available via the ENA Smarter Networks Portal using the Website link above
Publications	(none)
Final Report	(none)
Added to Database	10/09/18