Netzschutz im Verteilungsnetz bei sehr hohem Anteil dezentraler Erzeugung
Creators: name: Temkeng Zebaze, Rochnel
name: :Unav
Publisher: name: Fraunhofer-Gesellschaft
Year: 2021
Subjects: Netzschutz
Verteilungsnetz
Dezentrale Erzeugung

description: The energy transition is the topic at the center of most debates today. While in the past only consumers on the lower grid levels were connected, today decentralized generators such as photovoltaic systems, small home power plants and wind turbines are increasingly being integrated into the grids to ensure a 100% CO2-free energy supply by 2050. This is likely to change fundamental assumptions of the current mode of operation. Existing grid protection concepts will also be affected. For our safety, it is absolutely essential that the installed protection systems function properly at all times. Similar to household fuses that protect people, lines and appliances from overloads and short circuits, there are protection systems in distribution grids that ensure safe operation and thus prevent damage and large-scale power outages. However, it is not sufficiently known today how these protection devices will behave in future power grids. This Master thesis first deals with the development of future scenarios in distribution grids with regard to grid protection, then with the expansion of grid and system models and finally with the automation and implementation of simulation studies and their evaluation. In this master thesis, the first two chapters deal with the current situation in the electricity grid, taking into account a higher number of decentralized generators that are fed into the grid. Furthermore, the prerequisites that protective devices must fulfil in an electrical distribution grid are dealt with, and finally the different protection concepts that one has depending on the voltage level are explained. Chapter 3 deals with the planning and general design of the various protection concepts in a closed ring medium-voltage grid (previously selected from the Simbench website database), without decentralized generators. In chapters 4 and 5, first the short-circuit simulation is carried out to see whether our protection concept has been implemented and works as planned. After that, the next part is about automatizing the different simulations of short circuit calculations by varying certain parameters using programs like Python. Lastly, decentralized electricity generators are gradually added to the grid and the reaction and adaptation of our different protection concepts are simulated again. Chapter 6 analyzes how our grid would behave, if it were operated as an island grid: this is the system state in which a part of the electricity grid containing both generators and consumers is separated from the rest of the trans-European interconnected grid and its components. The consumers connected to the sub-grid continue to be supplied with electrical energy. Finally, based on simulations that have already been carried out automatically and with the help of various results, the future challenges and outlooks for grid protection in grids with a large number of generation plants are given. In Chapter 7, the objectives of this thesis are explained again, then the methods used to achieve these objectives, and finally the analysis of the results obtained through the different simulations.