The paper presents an approximate method for calculation of electrodynamic resistance parameters of a flexible bus-bar with bundled phases. Comparison of the approximate calculation results with the computer calculations using a FAZA software tool has been given in the paper. An evaluation of permissible aerial cable spacer compression forces for designed modern standard distribution substations of 330 and 550 kV has been provided in the paper. The paper proposes an algorithm for determination of dynamics parameters in a bundled phase with due account of influence pertaining to viscoelastic characteristics of damping spacers.

The paper shows non-efficient application of the existing economical models for determination of replacement time for transformers with long service life because these models do not take into account real changes in transformer parameters during its operational period. An improved mathematical model for estimation of replacement efficiency of power transformers which are used at substations of power distribution networks has been developed in the paper. The model makes it possible to determine an optimum replacement time and economically justified operational service life of the transformers.

The paper presents an implementation of a mathematical model for wye-connected current transformers in Simulink-SimPowerSystems environment.
TПЛ-10-type current transformer has been taken as an example for calculations that confirm an adequacy of the mathematical model implementation and the possibility of its usage for engineering analysis.

Mathematical relationships characterizing a storage impact on energy losses in case of different charge/discharge power ratio in the device have been obtained in the paper. The relationships have used as a basis for calculations that have estimated changes in energy losses for a wide scope of variants pertaining to setting up reference conditions and charge/discharge power ratio of the storage. The obtained results have made it possible to compare various storage operational modes on the assumption of an energy losses reduction criterion.

The paper considers stationary and transient processes of an asynchronous two-machine system. A mathematical model for investigation of stationary and transient modes, static characteristics and research results of dynamic process pertaining to starting-up the asynchronous two-machine system has been given in paper.

The paper proposes an analytical expression for calculating a manipulated variable of stator voltage in a frequency-controlled induction generator with a cage rotor of a wind power plant while regulating a constant value of the absolute slip of the generator. Comparison of the calculated results by the proposed expression and full differential equations of the generator (an equation of state) at steady state has confirmed a high accuracy of the analytical expression.

The paper investigates technical and economic indices (specific capital inputs, construction period, pay-off period, possible economically substantiated generation of electric power) of electric power plants using renewable energy sources under climatic conditions ofBelarus. The indices have been compared with the data of nuclear power engineering. The most efficient directions are wind and biomass power engineering. In accordance with its technical and economic and ecological indices the biomass power engineering is more profitable than nuclear, hydro- and solar power engineering.

Useful physical regularities of a reversible thermodynamic cycle for heat engines have been established in the paper. The engines are using fuel combustion products as a heat source, and the environment - as a heat sink that surpasses Carnot cycle according to efficiency factor.

The paper presents an analysis of specific features of lining thermal performance in electric-arc furnaces at various technological periods. It has been  shown that on the basis of mathematical modeling methods for thermal processes it is possible to predict power consumption of furnaces at the operational split schedule with due account of such furnace characteristics as capacity, lining materials, furnace idle times under closed and open conditions etc. The paper shows distinctions in thermal performance of acid and the basic linings in the electric-arc furnaces. The proposed approach allows to analyze thermal losses by heat conductivity and on accumulation by a refractory lining and rather accurately to determine the required balance sheet items while calculating power consumption during various periods of scrap melting for furnaces of various capacity.

A classification on systems for passive afterheat removal from reactor containment has been developed in the paper.  The classification permits to make a detailed analysis of various concepts pertaining to systems for passive afterheat removal from reactor containment of new generation. The paper considers main classification features of the given systems.

The paper considers modeling of dynamics on hot extrusion process for polyester fibre. New modifications of nonlinear dynamic models are have been proposed in the paper. The models in contrast with the known ones make it possible to take into account an effect of tensile stress magnitude and duration of its application on temperature of the hot extrusion, in order to achieve the desired values of strength and relative elongations of the polyester fibre. The proposed models are applicable for efficient solution of problems on synthesis of combined control systems for regulation of hot extrusion temperature.

The paper contains an analysis that reveals an influence of technological parameters of a cross-country pipeline on operational indices of a compressor station. An actual dependence of the gas pipeline capacity and consumed power of the compressor station and real indices of power efficiency of gas compressor units have been determined in the paper.