Protection and fault management in active distribution systems
The integration of renewable energy resources (RES), as a type of distributed generation (OG) units, is increasing in distribution, systems. This integration, changes the topology, performance and the operational aspects of conventional distribution systems. Protection is one of the main issues that...
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| Tipo de recurso: | tesis doctoral |
| Fecha de publicación: | 2016 |
| País: | España |
| Institución: | Universitat Politècnica de Catalunya (UPC) |
| Repositorio: | UPCommons. Portal del coneixement obert de la UPC |
| Idioma: | inglés |
| OAI Identifier: | oai:upcommons.upc.edu:2117/106486 |
| Acceso en línea: | https://hdl.handle.net/2117/106486 https://dx.doi.org/10.5821/dissertation-2117-106486 |
| Access Level: | acceso abierto |
| Palabra clave: | Àrees temàtiques de la UPC::Enginyeria elèctrica |
| Sumario: | The integration of renewable energy resources (RES), as a type of distributed generation (OG) units, is increasing in distribution, systems. This integration, changes the topology, performance and the operational aspects of conventional distribution systems. Protection is one of the main issues that are affected after the high penetration of OGs. Therefore, new protection methods are necessary to guarantee the safety and the reliability of active distribution systems. On the other hand, most RESs are interfaced with the AC grids through power-electronic devices. These interfaces consist of at least one AC/DC conversion units. Hence, using OC distribution systems can contribute to the loss/cost reduction, as some power conversion stages are eliminated. Enhancement in system stability, reduction of power losses, and power quality 1 improvement are other advantages of OC networks. For these reasons as well as the simple integration of electronic loads that are supplied by OC power, the concept of OC distribution systems has attracted a considerable attention over the last years. In 1 fact, MVOC and LVDC grids can be an important part of the future distribution systems. Furthermore, AC and OC system can contribute to construct hybrid AC/DC distribution systems. According to these significant changes in the distribution systems, it is necessary to modify the algorithm of existing protection methods or to propose new protection schemes for both active AC and OC distribution systems. Moreover, in conventional distribution systems, loads are supplied by upstream grid, i.e. transmission lines; therefore, when a fault impacts the upstream grid and the faulty part disconnected by the protection system, all loads connected to distribution systems are disconnected as well. However, in active distribution systems, DGs can support the on-outage zones if the grid equipped with an appropriate fault management system. Therefore, automatic self-healing methods can increase the network reliability and power supply continuity. To provide the self-healing capability, distribution grids should be equipped with adequate algorithms that are able to guarantee the continuous and optima! operation for the isolated section of the grid. In this thesis, differences between protection issues in OC and AC systems are investigated and analyzed. Then, based on this analyze, effective protection and fault management methods are presented far OC distribution systems and microgrids. In the other part of this thesis, a fault management and self-healing algorithm is proposed far active distribution systems. The proposed methods have been evaluated by the hardware-in-the-loop approach using real-time simulators and suitable controllers. |
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