In this masters thesis, we defined the concept of voltage flickering or so-called flickers in the network, which lead to flickering of light caused by changes in voltage in certain time intervals, the consequences of which can be due to changes in the load and an increase in the output power of the generator. After dealing with the basic terms, we got acquainted with the sources of the mentioned flickers. Then, mathematically and with the help of physical quantities, we presented the flickering, the permitted levels of flickering and the possibility of reducing the impact of flickering on the network. In the second part of the work, we analyzed the influence of the plant on voltage flicker levels according to the IEC 61000 – 3 – 7 standard. In the practical part of the work, we simulated the default network in the DIgSilent PowerFactory program package, which we calculated the flicker levels at certain places. With the help of EMT simulation, we obtained the voltage change values on certain buses, and with the help of a flickermeter, we calculated the long-term and short-term flicker values, which we compared with the permitted values from the standard, and reached a conclusion based on the comparison.