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Title: DC grid management and transient analysis of multi-terminal HVDC transmission
Author: Rafferty, John
ISNI:       0000 0004 5368 5621
Awarding Body: Queen's University Belfast
Current Institution: Queen's University Belfast
Date of Award: 2015
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With the advent of large scale offshore wind generation the world has taken a significant step closer to reducing its reliance on fossil fuels as the main source of electricity. To this end, plans in Europe have been proposed to interconnect a variety of renewable generation sources, predominantly wind sourced, via the construction of High Voltage DC lines into a Single Multi-Terminal DC (MTDC) grid, dubbed the European Supergrid, In order to meet a large portion of the total European demand. The object of this thesis is to address some of the issues involved with the Implementation of such a complex system. This work presents possible grid management strategies for the safe and efficient operation of MTDC systems to ensure adequate security of supply under varying grid conditions. It proposes power sharing strategies within MTDC systems incorporating several sending and receiving end terminals based on "power priority" at the receiving end to meet demand and ensure stable system operation is maintained. Further, it proposes the utilisation of DC grid management strategies for the provision of frequency support within MTDC systems through the redistribution of active power during periods of load imbalance within the AC system, Additionally, it proposes a potential method of detection of frequency events In onshore AC systems for interconnected decoupled offshore wind systems via utilisation of DC grid voltage manipulation, Finally. it provides a detailed analysis of the behaviour of a two-level AC/DC converter under DC fault conditions (both line-to-line and line-to-earth) from circuit analysis based on the converters behaviour post-fault. For line-to-earth faults, it analyses the effect of different earthing configurations with an,aim to provide additional insight into the differing behaviour of the converter post-fault and thus assist in the development of optimised fault detection and isolation protocols, as well as reconnection procedures post-fault.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available