One of the causes of local overheating of submersible electric motor caused by the presence of a significant variation of electromagnetic parameters of rotor packages (RP) in the assembly of submersible electric motor is investigated in this paper. Due to the presence in the assembly of RPs with an active resistance much lower than the average resistance of the assembly, the electrical losses in RPs with resistance higher than the average increase, respectively, their heat generation increases. With the help of statistical analysis methods, the distribution of electromagnetic parameters as a two-dimensional random variable was investigated, the "convolution" of the two-dimensional distribution law was constructed. The analysis of the "convolution" of the two-dimensional law of distribution of electromagnetic parameters of the RP showed that there is a high probability of a significant scatter of parameters of the RP in the assembly.

Keywords: submersible electrical motor, rotor package, statistical analysis, local overheating, interrepair period

The article proposes a method for determining the optimal location of a self-supporting fiber-optic cable laid along the supports of high-voltage power transmission lines. The methodology is focused on the use of both a manual calculation method and with the use of electronic computing equipment.

Keywords: fiber-optic communication line, electric field, induced voltage potential, electrothermal degradation, optimization of placement of self-supporting fiber-optic cable

In the work, a method was implemented that allowed estimating the parameters of a control object based on the objective function, the least squares method, and the solution to the system of nonlinear equations was the Levenberg-Marquardt method. The numerical and laboratory experiments carried out allow us to speak about the effectiveness of the proposed method.

Keywords: identification, optimization, least squares method, Levenberg-Marquardt method, differential equation

The article raises the issue of maintaining the stability of the power system, including maintaining the balance of electric power. The occurrence of power imbalance can be determined by a criterion such as frequency. The authors have proposed a method of maintaining frequency including maintaining power balance in the power system by changing voltage on electric energy consumers, a hypothesis has been set and a corresponding laboratory study has been carried out, as a result of which dependence of frequency change on voltage of some electric power receivers has been obtained. A device an automatic unloading regulation of voltage has been developed and described, which will make it possible to supplement the existing emergency control equipment.

Keywords: renewable energy sources, grid inverters, mode parameters, Clark conversions, Park conversions

The article discusses the features of the use and applicability of identification of parameters of the equivalent circuit of an submersible electric motors. The possibilities of technical implementation with a given accuracy are evaluated for definition the parameters of submersible electric motors substitution circuits under various external influences, as well as when designing submersible electric motors as an integral part of the electro-technical complex of electrical submersible pump units.

Keywords: submersible electric motor, electrical submersible pump unit, identification of parameters of the equivalent circuit of an asynchronous electric machine, mathematic simulation, crude oil production