The paper presents methodical principles for analysis of opened 10(6) kV power network modes with symmetrical and asymmetrical phase loads. A mathematical model and an algorithm of sectional point optimization in the distributive 10(6) kV power network has been modified in the paper. The problem is solved with due account of  power supply network of 110 kV and higher and a number of additional limitations. The obtained algorithms serve as a basis for development of the required complex of industrial programs for solution of technological problems pertaining to operation of urban 10(6) kV power networks.

Development of a system for relay protection command transmission by high-voltage lines is shown in the paper. The paper describes an architecture of the system, main principles of its operation, engineering aspects of the development that is accomplishment of technical requirements, solution of trades-off. Justification of the selected design and an algorithm of the reliable detection of relay protection signals are given in the paper.

The paper considers a power scheme and a control system of  two-member frequency converter with voltage inverter which is designed for power supply of a bearing ring demagnetizer inductor. An algorithm for commutation of power keys is proposed in the paper. The algorithm makes it possible to obtain an inductor current which is close to the given current at low commutation frequency of power equipment.  Simulation modeling within the system of computer «Mathlab Simulink» modeling has been applied with the purpose to evaluate the algorithm quality. The obtained charts of frequency converter electrical variables have shown practical coincidence of the given and actual currents that testifies about high efficiency of the proposed commutation algorithm. In addition to this an analytical expression for calculating filter capacity of  demagnetizer inductor  voltage inverter has been developed in the paper.

CoDeSys programming system is considered as the most complete version of software for programmed logical controllers (PLC) that meets requirements of IEC 61131-3-standard. The given software is the most suitable for simulation and development of control system algorithms and execution of semi-full-scale tests without involvement of an actual object. Programming medium operated at a personal computer in Windows medium. As CoDeSys provides a machine code it is rather easy to support its programming and its minimum support presupposes selection of IN/OUT and program debugging functions.

The investigations have been directed on optimization of an electric drive operation with varying inertia moment. The whole software developed for the solution of the considered problem, has been written and realized in the CoDeSys programming system. «Modified principle of maximum» of V. I. Panasiuk is applied as a body of mathematics that allows to obtain positive results of the investigations.

The paper presents the developed methodology that has been used for making calculations of main reliability indices for existing electric power supply circuits of AIC consumers. Some measures pertaining to provision of higher reliability are given in the paper. The paper contains calculations of changes in respect of reliability indices and reduction in cost of supply lost due to power supply interruptions in case of introduction of the proposed  measures.

The paper presents a methodology for calculation of recuperative heat exchangers applied at heating continuous furnaces of press-forging production at machine-building enterprises. Technical and economic calculations of an optimum air heating temperature have been made taking needle-shape heat exchangers in the RUE MAZ heating continuous  furnaces as an example while varying furnace capacity, cost of power carriers and heat-exchange devices.

The paper considers a problem pertaining to better regulation of the superheated vapour tem- perature. This improvement can be achieved while determining dynamic adjustment parameters of automatic regulation systems (ARS) due to reduction of error at approximation of experimental transient characteristics of leading and inertial areas of an object to be regulated by turning to open-closed regulation system and by using an «areas» method.

The paper presents an algorithm of signal processing against actual leakages simulated with the help of an experimental thermo-physical stand. The algorithm for evaluation of leakage coordinates has been developed in the paper and it is based on the signal processing  which are received by every four microphone transducers. Higher accurateness has been achieved while applying an area method of local coherence.

A correction factor that denotes an increase of heat transfer coefficient of a corridor tube bank at longitudinal pitch decrease is widely used in educational literature. The paper shows that such inverse relationship is not confirmed by the majority of scientific investigations. Additional experimental data are given in the paper. The correction factor for consideration of the influence of corridor tube bank geometrical characteristics on heat transfer is offered to be used in engineering calculations.

The mathematical model has been developed and calculation of solid particle movement due to the action of swirling gas flow in a cylindrical element has been made in the paper. The paper investigates hydrodynamics of gas flow and forces influencing on a solid particle, both in the basic flow and during a contact with cylindrical surface. He obtained data can be used for research of processes pertaining to division of two-phase flows in a vortical device.

The paper considers power-efficient systems applied for heating building and structure external walls with ventilated air spaces and prescribes directions and problems pertaining to power-efficiency improvement of such systems.