The specificity of overhead power lines is associated with the fact that the length of conductors between the supporting structures can reach tens of thousands of meters. Wires and their components are exposed to climatic factors, viz. wind, rain, ice, snow. As compared to other structural elements, conductors are of the highest flexibility and lowest rigidity, and, therefore, they are the most sensitive elements to these effects. Since the early fifties of the XX century, the increase in energy consumption has caused the construction of high and ultra-high voltage overhead lines with split phases. For these types of conductors, new forms of oscillations have been noticed in the areas between the struts, the essence of which is torqueing the split phase. As a result, there is a violation of the torsional stability of the phase: collision of wires in the middle of sub-span and friction of wires of stranded conductor against each other, which leads to damaging conductors and, as a consequence, to disruption of power supply to consumers. Almost any overhead lines may be subjected to oscillations of wires in the span under the influence of wind. One of the types of such mechanical oscillations is galloping, i. e. low-frequency oscillations of wires with an amplitude reaching the value of the boom of wire sagging, and, taking into account the possibility of elongation of the wire, even exceeding it. Fluctuations in the galloping can cause significant mechanical forces and last long enough to lead to the destruction of structural elements of power lines, viz. wires, insulators, fittings and even pillars. Due to the large amplitude of oscillations, conductors of neighboring phases can approach each other at an unacceptable distance, resulting in a short circuit. The boundary value problem of the torsional stability calculation of the split phase with a given multiplicity of splitting has been set and solved. The critical lengths of the sub-spans at which the stable violation of torsional stability is most likely have been determined. A computer program has been developed, which can be used in the design of high-voltage lines with split phase.

The method of calculation of the steady-state mode of the open city distribution electric network with small generation sources is offered. It is shown that the city electric network consists of passive and active physical elements. Passive elements include power transformers and linear regulators, overhead and cable power lines, current-limiting reactors, etc. Active elements of networks are power sources (transformer inputs of low voltage of feeding substations and distributed small generation sources) and loads, mathematical models of which can be various. Power sources in urban distribution networks of 10 kV and below are classified by type and power and can be of two kinds, viz. power feeding centers of the network and small generation sources. Consumer loads are modeled by current sources connected to network nodes. The parameters of the current sources are usually graphs of the change of the module of the actual current value and the power factor in time. The values of these parameters in single-line substitution schemes of 6–10 kV distribution networks with isolated neutral are assumed to be average for three phases. The power centers are transformer inputs of low voltage power substations of the main electric networks of 35 kV and above, equipped with digital devices of the account of the electric power connected to the automated system of control and accounting of power resources. The developed technique allows receiving the refined balanced calculation model of the steady mode of the open city network for the set time of the daily schedule. It includes the sequential distribution of the specified power of each network power supply between its loads, followed by clarification of flows and power losses in the sections, as well as voltages and actual loads in the nodes of the scheme by the overlay method.

Load profile alignment based on optimal power consumption management is considered to be one of the main ways to ensure efficient operation of energy systems in the short-term planning. Alignment load profile with a view to reducing costs can be implemented with the aid of consumers’ involvement by administrative and economic measures. Administrative measures are associated with the forced restriction of consumer loads in certain intervals of the planning period. On one hand, these measures provide benefits to the power system by alignment load profile, and on the other hand, they cause detriment to consumers. Ultimately, in some cases, for the whole power system, the detriment may be greater than the benefits. Therefore, it is advisable to use administrative measures in conditions of shortage of power and electricity in the power system. Optimal planning of short-term regimes of power systems according to rigid load profile received after alignment can be carried out by traditional methods. The solution of such a problem ought to be initially carried out under conditions of non-rigid load profile resulting from the directive use of administrative and economic measures carried out with the help of specially developed models. In this regard, the paper proposes a mathematical model of the problem of optimizing load profile of regulated electricity consumers to be used for optimal planning of shortterm power system modes, an algorithm for optimal planning of a short-term power system mode with optimizing load profile of regulated power consumers. Also, algorithms are proposed for accounting for simple and functional constraints in the form of equalities and inequalities when optimizing load profile. The effectiveness of the described algorithm for optimizing the short-term mode of the power system, taking into account the optimal load control of adjustable electricity consumers, has been studied using the example of optimal coverage of the load profile of power system, which contains two consumers with adjustable load profile, and two TPPs. Based on the calculated-and-experimental studies, it was determined that the proposed mathematical model of the problem is adequate, while the developed algorithms for optimal planning of short-term power system modes with optimization of load profile of regulated electricity consumers and taking into account various types of limitations are of high computational qualities.

The paper presents a fragment of on-going investigations directed on creation of optimal information environment that ensures an access to the R&D publications from the known scientific journals and other scientific serials which are necessary for qualitative execution of scientific and technological activities on priority areas in highway engineering. A citation analysis has been applied while using data of Journal Citation Reports for selection of world scientific publications which are necessary for execution of investigations on heat and mass transfer in road dressings. Their deformations occur under various climatic conditions due to heat and mass transfer processes, interaction of transport flows and road surface that leads to crack formation in depth and on the surface of road dressings. Structure of constructive layers especially which are created with the help of technogenic wastes (asphalt-, reinforced concrete, concrete, brick scrap and products of their recycling, various wastes of production etc.) exerts an influence on heat and mass transfer. The paper presents results of investigations on heat flows, boundary layers according to viscosity, air velocity, geometric characteristics, permeability, capillary pressures in materials. It has been shown that calculations based on principles of complex number usage have specific features in engineering practice: it is required to observe their accuracy in approaches, calculation reduction due to some accuracy degradation as a consequence of transition from complex numbers to their modules with exclusion of phase shift account and related with propagation of thermal waves. In this respect calculations of heat resistance without phase shifts are considered as rather important if they are in agreement with principles based on the fact that a complexity is characterized by thermal absorptivity of the material in a great number of calculations. The investigations have been supported by Henan Center for Outstanding Overseas Scientists, Grant Number GZS 2018006 (People’s Republic of China, Henan Province).

The influence of hydration of the components of combustion (air-oxidizer and – in some cases – fuel) including hydration in the conditions of substitution of natural gas by alternative gas fuels, viz. by coke blast furnace mixture and natural blast furnace mixture – on energy efficiency of the use of different fuels has been determined. Calculations of fuel saving for substitution of natural gas (NG) by wet process gas (blast furnace gas (BFG), coke gas (CG), their mixtures) were performed taking into account real technological parameters (on the example of a specific metallurgical plant). All the calculations were performed within the framework of the author’s methodology on fuel substitution grounded on the 1st and the 2nd laws of thermodynamics. The analysis of possibility for saving or overspending NG is performed in the conditions of preservation of the flow of the used total enthalpy (as the main requirement of the methodology that had been proposed) and of taking into account the corresponding efficiency of fuel use. The calculation of the required heat flow of natural gas combustion depending on the content of wet blast furnace gas in NG + BFG mixtures for the cases of NG substitution by process gases has been carried out. It is established that the presence of moisture in the fuel-oxidation mixture always reduces the efficiency of the combustion chamber or the energy process and the unit. In order to increase the efficiency of a high-temperature furnace (boiler), it is necessary to provide heating of combustion components when utilizing the heat of the outgoing combustion products. It is shown that the efficiency of the fuel-using system can be significantly increased when the potential (excess total enthalpy) of the working fluid (combustion products) is activated. There are additiоnal benefits due to the fact that the existing heat of products of combustion with humid air in a full range of temperatures – from the theoretical combustion temperature to ambient temperature under conditions of equilibrium, including account of the heat of condensation – increases with increasing moisture content of the initial components of combustion, viz. air-oxidizer and/or fuel gas.

The combustion of hydrocarbon fuels in the chambers of heat generating plants is one of the main sources of pollutant emissions. Environmental standards and rules that limit emissions are becoming more stringent and their implementation requires the introduction of advanced technologies and equipment. The main device in combustion systems are blow burners, the design of which largely determines the level of emission. The article considers factors that intensify the formation of normalized pollutants, provides global chemical reactions, various types of mechanisms, and kinetic schemes. Based on the analysis of modern methods for reducing harmful emissions, the most effective design solutions for mixing devices, nozzles and systems for distributing the flow of fuel and air supplied to combustion are determined. A comparative analysis of the methods and conditions for determining the emission class of the burner device is carried out depending on the selected units of measure, the coefficient of excess air (oxygen concentration in flue gases), air humidity and the initial composition of natural gas using examples of EU and EAC standards. The methodology for calculating the emissions of nitrogen oxides depending on the measurement conditions is given. The conversion factors for the values of pollutant emissions from the accepted units in the EU (mg/(kW×h)) into the units indicated according to the EAC environmental rules (mg/m3) taking into account the respectively normalized coefficient of excess air are obtained. As a result of the calculations, the types of burners were determined by emission classes corresponding to the applicable environmental standards and rules in the Republic of Belarus, depending on the heat output of the boiler plants.

In the first part of the paper the theory of infrared radiation and the use of nondestructive measurement of electrical devices by means of thermovision are under analysis. In the second part of paper basic principles and application of non-contact temperature measurement are examined. In the third part of paper thermal processes in distribution oil transformer – temperature in dependence on height of oil transformer and temperature distribution in sectional plan of oil transformer – are considered. In the fourth part of paper, by means of the experimental measurements and subsequent analysis, practical thermal imaging and contact thermal measurements by optical detectors for the diagnosis of distribution oil transformers in the field of mechanical strength of windings are shown. In this paper, we wanted to show out the possibility of using thermal measurements in this field of analysis and detection of quality of winding for distribution oil transformer. It is possible to use these methods to localize places of faults, and they are also applicable for the diagnosis and detection of disorders of the quality of materials and other anomalies during operation of the equipment. By means of the experimental measurements followed by diagnostic analysis the practical use of thermovision and optical sensors for diagnostics of power oil transformers in field mechanical strength and quality of winding is demonstrated.