PhD defence by Siavash Beheshtaein on Advanced Protection Strategies for AC and DC Microgrids
14.11.2018 kl. 13.00 - 16.00
Siavash Beheshtaein, Department of Energy Technology, will defend the thesis "Advanced Protection Strategies for AC and DC Microgrids".
Advanced Protection Strategies for AC and DC Microgrids
Professor Josep Guerrero
Associate Professor Tamas Kerekes
Associate Professor Dezso Sera, Dept. of Energy Technology, Aalborg University (Chairman)
Mehdi Zadeh, Norwegian University of Science and Technology (NTNU), Norway
João P. S. Catalão, University of Porto, Portugal
The microgrid is a cluster of Distributed Generations (DGs), energy storage systems, loads, and lines that can operate in both islanded and grid-connected modes. A microgrid needs to have a smooth transition between different operation modes and protect itself from any disturbances in the grid. In addition, for objectives such as reducing the power loss, increasing the reliability, and maximizing the system loadability, a microgrid needs to have a flexible topology. All these requirements result in some serious protection challenges. In addition, in a microgrid with a high penetration of DG, the sudden connection/disconnection of a large number of them may dramatically affect the fault current level.
To deal with the aforementioned shortcomings, some control-based fault current limiters for voltage- and current controlled-modes voltage Source Inverters are presented in this dissertation. Unlike most of the FCLs, which are external devices, the proposed method is a controlled-based method and, therefore, has a low implementation cost. In order to deal with the main challenges of the microgrid protection, two types of high-frequency harmonic injection based protection systems (communication-assisted and communication-less) are proposed to detect and isolate the fault without being affected by topology change and DG impacts. Finally, two different methods based on single-ended and double-ended approaches are proposed to locate the fault. In the single-ended method, once the fault happens, the closest DG, which has the lowest voltage amplitude, detects the fault. However, in the double-ended approach, two closest selected DGs are identified based on two criteria and these two DGs inject two HFH signals at two distinctive frequencies. The measured line impedances from these DGs terminals are fed to a multiple support vector machine to locate the faulty line. The main benefit of these methods is that the fault locating is carried out without any additional devices, therefore these methods have a very low implementation cost.
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ALL ARE WELCOME. THE DEFENCE WILL BE IN ENGLISH.
AFTER THE DEFENCE THERE WILL BE AN INFORMAL RECEPTION AT PONTOPPIDANSTRAEDE 111 IN ThE COFFEE ROOM.
Department of Energy Technology
Pontoppidanstræde 111, auditorium 1.177