The purpose of this study is to study the effect of loading power transformers (PT) in their continuous use on their energy efficiency on a real-life example of existing rural electric networks. It is noted that the vast majority of PT in rural areas have a very low load factor, which leads to an increase in specific losses of electric energy when this is transmitted to various consumers. It is planned to optimize the existing synchronized power supply systems in rural areas by creating new power supply projects in such a way as to integrate existing power sources and ensure the most efficient loading of power transformers for the subsequent transfer of these systems to isolated ones that receive power from distributed generation facilities. As an example, we use data from an electric grid company on loading power transformers in one of the districts of the Irkutsk region. Issues related to the determination of electric energy losses in rural PT at different numerical values of their load factors are considered. A computing device was developed using modern programming tools in the MATLAB system, which has been used to calculate and plot the dependence of power losses in transformers of various capacities on the actual and recommended load factors, as well as the dependence of specific losses during the transit of 1 kVA of power through a power transformer at the actual, recommended and optimal load factors. The analysis of specific losses of electric energy at the actual, recommended and optimal load factors of PT is made. Based on the analysis, the intervals of optimal load factors for different rated power of PT of rural distribution electric networks are proposed. It is noted that to increase the energy efficiency of PT, it is necessary to reduce idling losses by increasing the load of these transformers, which can be achieved by reducing the number of transformers while changing the configuration of 0.38 kV distribution networks.

The article presents calculations the additional electric loss in the case of three-phase voltage system unbalance in the real rural electrical distribution networks (0.38 kV). Measurements were carried out at substations that receive power from distribution substation “Petropavlovsk”. Measurements were carried out using a certified device “Resource-UF2M”. Also presented are graphs of changes in currents/voltages of the negative-sequence and zero-sequence, electric loss and other parameters. The results of the economic assessment of electricity losses are presented. As a result, the proposed method for reducing the power loss factor, that can reduce the losses of electricity.

Study of changes in quality indicators and an increase in additional losses of electrical energy in rural distribution networks of 0.38 kV in the village (Vishnyakovo, Irkutsk region). The measurements were carried out by a certified device “Resource-UF2M”, which records changes in the quality indicators of energy efficiency, but does not record additional losses of electrical energy associated with this changed quality. Therefore, based on the obtained measurement data, we used the developed computer program “Asymmetry” to calculate the required power quality indicators, as well as additional electrical energy losses caused by a change in these indicators. Based on the results of measurements and calculations, time diagrams were built, and an analysis was made of quality indicators and additional losses of electric energy in the existing 0.38 kV networks.

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The guidelines for the design of rural and urban power supply systems do not consider the issues of reactive power compensation and reduction in additional losses due to unbalanced and non-sinusoidal conditions. At the same time, today's rural power consumers have a great number of non-linear loads in their residential premises. Moreover, the unbalanced phase currents and voltages are an established fact. The paper aims to demonstrate the extent to which power quality and losses vary in real rural 0.38 kV networks. To this end, the objectives were posed to study the operation of two facilities: 1-switchgear at the cottage (with an installed capacity of 15 kW); 2 -switchgear at the communal entrance hallway for 60 apartments in an apartment building (with an installed capacity of 75 kW).