The master's thesis presents an analysis for the connection of small photovoltaic power plants to the low-voltage network.
The assignment first presents the basic issue of connecting scattered sources to the distribution system. In the following, a few words are dedicated to distributed energy sources, where the emphasis is on small photovoltaic power plants. The importance of self-supply, the currently valid regulation on self-supply of electricity from renewable sources, the basics of the distribution system and the SIST EN 50160 standard are also presented. This is followed by a description of the PIS ELJ information system, applications with a database of measurements from advanced meters, and the software tool QGIS - KN3. In the central part of the thesis, the calculation and use of all tools in the analysis for the connection of small photovoltaic power plants are presented in more detail, where the calculations are shown on examples from practice. The calculations are compared with measurements before and after the connection of small photovoltaic power plants, where the correctness of the results and the actual influence on the voltage conditions are proven. An example of calculating the impact of connecting solar power plants to a stronger network and to a network that does not allow the connection of photovoltaic power plants due to weakness and poor electrical conditions is also presented.
The results show that the calculation in the program gives correct results, and that the mutual influence of the connected solar power plants calculated by the program is comparable to the realistic situation on the network. In advanced user meters measurements, the voltage rises caused by the connected mFEs are expressed by pronounced local voltage rises. Despite the small impact of the new power plant, the connection of photovoltaic power plants to the weak grid is not possible due to the high existing voltage.
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