ВПЛИВ ОПОРУ РЕЗИСТОРА ЗАЗЕМЛЕННЯ НЕЙТРАЛІ НА РЕЖИМИ РОБОТИ РОЗПОДІЛЬНИХ НАПРУГОЮ 20 КВ

The article examines the impact of different modes of neutral grounding on the operating parameters of 20 kV distribution networks, in particular, the selection of the optimal resistor resistance for resistive neutral grounding. One of the main tasks is to improve the efficiency of distribution networks of the UES of Ukraine by switching from a voltage of 10 kV to 20 kV. This solution is aimed at reducing power losses, increasing the amount of transmitted energy and improving the operation of relay protection. In the context of such a transition, the choice of the method of grounding the neutral of the power transformer is particularly relevant, which significantly affects the reliability and safety of operation of electrical networks. In the study, an analysis of the effect of resistive grounding of the neutral of the transformer on the operating characteristics of the 20 kV network was performed, as well as determination of the optimal value of the resistance of the resistor. The article presents the results of a comparison of a network with an isolated neutral and resistive grounding. The main operating parameters, such as short-circuit currents, overvoltages on undamaged phases, power losses and operation of relay protection, which have a significant impact on the stability and safety of network operation, are analyzed. Modeling is performed using the PowerFactory software complex, which provides the ability to accurately reproduce the real operating conditions of electrical systems. To conduct the research, a simulation model of the distribution network was created based on a two-transformer 110/20 kV substation, which includes two sections with outgoing lines of different lengths and loads. Special attention was paid to the selection of the resistance of the neutral grounding resistor and its influence on network parameters. Four options were considered in the study: isolated neutral and resistive grounding with a resistance of 10 Ohm, 15 Ohm and 20 Ohm. It was established that in order to ensure stable and safe operation of the distribution network, it is important to correctly choose the neutral grounding method. The best option is resistive grounding with a resistance of 15 Ohms, which allows you to reduce power losses, provides a sufficient level of currents for the effective operation of relay protection, and minimizes the risks of overvoltages on undamaged phases. This study is important for increasing the reliability of the operation of distribution networks and the security of electricity supply, especially in the context of the modernization of Ukraine's UES networks.