The present report deals with economic issues of selecting means ensuring the capacity adequacy of electric power systems. Cost analysis of various engineering measures ensuring the capacity adequacy has been performed, namely: construction of backup generating facilities, erection of new power transmission lines, or increase of transmission capacity of existing power lines. The cost-based analysis has been conducted based on investment programs and regulatory acts in place. Recommendations on developing computational models of power systems have been given based on the results obtained in order to assess the capacity adequacy parameters, with account made for the cost of various engineering measures to be taken for their improvement.

In prevailing practice of calculation of capacity adequacy parameters, the structure of electric power systems transmission network is presented as a transport model which makes an aggregate of reliability zones and tie-lines between them of a given transmission capacity. The main objective of calculation of capacity adequacy parameters is to determine the required generating capacity redundancy level, i.e. the values of the capacity margin and its location within electric power systems to ensure a required level of capacity adequacy. With that in mind, when evaluating and accordingly when forming transport models, it should be useful to take into account the transmission constraints only for those power grid segments, whose cost of transmission capacity increase is comparable with that of construction of new generating facilities.

On the basis of calculation data, one may state that for overhead electric lines of short or average length the cost of 1 kW of its transmission capacity will be considerably lower than that of installed capacity of a new generating facility, with the above costs comparable only with the length of the line close to its critical value. When forming transport models of electric power systems, it is useful to take into account not only the distance between electric power system nodes, but also their potential need of margin capacity. As far as remote nodes are concerned, if these are of low need in margin capacity, it should be reasonable to separate them as specifi c reliability areas.

The object of the study are the steam networks of Smolensk. The purpose of the article is to determine the influence of beyond-design modes on the functioning of the entire steam supply system. Beyond-design modes of industrial steam supply pose a serious problem for all elements of the system: they make it difficult to fully load the turbines, lead to high excess losses of heat and coolant, and also lead to disruption in technological processes. Analysis of statistical data on reduction of industrial steam extraction has been carried out, archived data on heat supply and consumption have been processed and analyzed over the period from 2007 to 2017. A methodological error is found in the accounting of thermal energy and coolant by variable pressure drop flowmeters designed to handle superheated and dry steam. Calculation of heat network quality indicators is carried out, maximum permissible lengths of steam pipeline sections are determined, enabling to transport superheated steam to consumer regardless of the load reduction. The influence of the extent of wear of insulation and the diameter of the pipeline on the change in the aggregate state of the coolant has been analyzed, and the maximum load for steam networks has been found as being 30% of the designed one. It has been established that, with industrial extraction decreased, the CHPP is forced to disengage the turbine from operation, since a load drop of more than 50% brings the turbine to the condensation mode and reduces the technical and economic performance of the CHPP to the threshold permissible values. The obtained results enable to draw a conclusion that such a problem as beyond-design modes, especially in steam supply systems, requires an integrated approach, since the influence on an individual element in isolation from the system leads to a change in the performance of the remaining elements.

The influence of the periodicity of diagnostic measurements on the operational state of high-voltage transformers is considered. Examples of defects of switching devices of converter transformers and methods for their detection are given. The rationale for the importance of recognition of defects at an early stage of their occurrence is given. The influence of the multiplicity of overvoltages on the service life of converter transformers in the aluminum industry is investigated. Based on the analysis of the service life of converter transformers of one of the powerful aluminum plants, where 83% of converter transformers have exhausted their standard service life, it is shown that in 40% of cases it would be possible to avoid their failures, with timely detection and elimination of emerging defects. Examples of defects of OLR (on-load regulators) of converter transformers and methods for their detection are given. The importance of recognition of defects at an early stage of their occurrence is substantiated. A method for chromatographic analysis of dissolved gases in transformer oil has been developed for the qualitative determination of defects and ways to eliminate them. Examples of diagnostics of converter transformers at operating voltage and working load are given, providing the best quality operational characteristics of converter transformers. The periodicity of diagnostic measurements and the reduction of defects and failures has been substantiated. The question of diagnosing the state of the converter transformer TDNP-40000/10 at an enterprise of the aluminum industry is investigated. Currently, diagnostic methods are being developed based on chromatographic analysis of dissolved gases in transformer oil. The presented method of evaluating the operating parameters of transformers allows for the safe operation of high-voltage transformers and enables to increase the reliability of the power supply scheme of aluminum industry plants.

One of the most important issues for modern domestic power industry is the creation and further widespread introduction of solid propellant energy units for super-critical steam parameters with high efficiency (43–46%) and improved environmental parameters. This will significantly reduce the use of natural gas.

At the same time, one of the major drawbacks of the operation of pulverized coal power units is the need to use a significant amount of fuel oil during start-up and shutdown of boilers to stabilize the burning of the coal torch in the variable boiler operating modes.

In this regard, solid fuel TPPs need to be provided with fuel oil facilities, with all the associated problems to ensure the performance (heating of fuel oil in winter), reliability and safety. All of the above problems increase both the TPP capital construction costs, and the electricity generating cost.

A practical solution to the above problems at present is the use of a plasma technology for coal torch ignition based on thermochemical preparation of fuel for combustion. The materials of the developments of JSC “NPO CKTI” on application of plasmatrons in boilers of thermal power plants at metallurgical complexes of the Russian Federation are also considered.

Plasma ignition systems for solid fuels in boilers were developed by Russian specialists and were introduced at a number of coal-fi red power plants in the Russian Federation, Mongolia, North Korea, and Kazakhstan. Plasma ignition of solid fuels is widely used in China for almost 30% of power boilers.

The introduction of plasma-energy technologies will improve the energy efficiency of domestic solid-fuel thermal power plants and can be widely implemented in the modernization of boilers.

During the construction of new TPPs, the construction of fuel oil facilities can be abandoned altogether, which will reduce the capital costs of the construction of thermal power plants, reduce the construction footprint, and increase the TPP safety.

The crisis of heat exchange at boiling of water in porous structures used for cooling of heat-stressed surfaces of various aggregates is investigated. The study refers to thermal power installations of power plants. The experiments were carried out on a stand with heat supply from an electric heater. Cooling of heat-exchange surfaces was performed by water supply to porous structures with diff erent cell sizes. It is shown that in porous cooling systems of elements of heat and power plants processes of fl uid boiling take place, and at high heat fl ows it is possible to approach a crisis situation with overheating of the heat-exchange surface. The heat exchange processes are described, the infl uence of thermophysical properties of heat exchange surface is shown, and optimal sizes of porous structure cells are determined. A calculated equation is obtained for determining the critical heat fl ux at high pressures. The calculation of the critical load with respect to the examined porous structures was carried out with taking into account the underheating and fl ow rate, from which it follows that the underheating of the liquid enables to expand slightly the heat transfer capabilities in a porous cooling system. The experimental data of the investigated capillary porous cooling system operating under the joint action of capillary and mass forces are generalized, and its characteristics q=f(ΔT) are compared with boiling in large volume, heat pipes and thin-fi lm evaporators. The limits of diff erent capillary-porous coatings are given. High heat transfer boosting is provided by combined action of capillary and mass forces and has advantages in comparison with boiling in large volume, thin-fi lm evaporators and heat pipes. It is shown that the results of theoretical calculations conform well with experimental data.

An analytical model of the operation of the relay protection of power systems is presented, which takes into account such types of failures as unwanted operation, failure to operate, as well as defects dangerous from the point of view of unwanted operation and failure to operate. Operability checks of relay protection of power systems are conducted with a constant period. The listed events can be divided into two groups: random and regular ones. The presence of random and regular components of events of recovery of relay protection of power systems can be correctly taken into account in the framework of the apparatus of the theory of Markov processes. The model is based on the description of the process of operation of relay protection of power transmission line by a semi-Markov process. The functioning of the system in time is presented in the form of cycles. The cycle of the functioning of the system consists of a subset, where the system is functioning and verifi ed, and a subset, in which it is restored. The model is implemented in a graph with 9 states. Probabilities of events describe the process of changing states on a discrete set of states of relay protection of the power system. The probability of a change of states is the initial characteristic of a semi-Markov process. This model has enabled to obtain the dependence of operation and reliability parameters on the frequency of regular checks. It is established that the frequency of regular checks with the exponential distribution law overstates the value of the unavailability factor, since the time of the onset of a periodic check is greater than the mathematical expectation of a given value of the periodic check under a random distribution law. With a signifi cant time between checks, or in absence of periodic checks, the unavailability factor tends to a value that does not depend on the way of setting the time between periodic checks.

Expediency is considered of substitution of water heating and transition to air heating that can be implemented with “air-air” type heat pumps (HP). The absence of water pipelines raises the reliability of heating systems. In addition to improved reliability, heat pumping systems ensure comfortable conditions for consumers at intervals between the heating seasons, when the central water heating is disabled.

The “air-air” type HP use the ambient air as a low-grade heat source (LGHS). At low air temperatures, transformation ratio μ is about 2 and would rise to 3÷4 at higher air temperatures, which ensures high cost-efficiency of heating systems based on heat pumps. The heating season can generally be divided into two periods. One of the periods is characterized by the highest ambient air temperatures (–5÷8°С). This period is rather long and, in warmer winters, can last for about 4000 hours per heating season, or longer. This is the period, when the heat pump operates efficiently at a transformation ratio above 4.

The other period, when the ambient temperature falls below –10÷ –20°С, generally lasts for a small number of hours, which makes about 15÷18% of the total duration of the heating season. At this period, the efficiency of the heat pump would decrease to μ =1.9÷2. Yet, even with such an efficiency, a heat pump delivers twice as much heat as the electric power it consumes.

Therefore, in regions with a long period of temperatures within the range of –5÷8°С during a heating season, air heating based on HP can be advantageous compared to water heating.

A solution to the problem of modeling the removal of a finely dispersed phase from stack gases and process gases at power engineering and petrochemical enterprises using a column apparatus filled with new highly efficient random and structured packings is considered.

The use of diffusion and cell models of the flow structure for calculating a concentration profile of particles settling on a liquid fi lm in apparatuses filled with various packings is shown. Accounting for the deposition of finely dispersed particles from gases on the interfacial surface of the liquid fi lm flowing down along the packing is carried out using a bulk source of mass. The model of turbulent-inertial sedimentation of particles is adopted. The main parameters of the model are the coefficient of turbulent migration of particles to the fi lm surface on contact devices, a modified Peclet number with a backmixing coefficient, and the number of complete mixing cells. This approach can be generalized to a wide class of fi lm-type apparatuses for wet gas cleaning with the aim of designing them or choosing modernization options. Expressions are obtained for calculating the efficiency of aerosol separation on packings as well as the required depth of the packed bed for a given efficiency.

Results of calculating the efficiency of gas purification from aerosols with the use of various types of packings in scrubbers as well as the required depth of the packed bed for a given efficiency are presented. A graphical dependence of the power spent on gas cleaning in apparatuses with different packings is given. Results of solving the production problem of cleaning pyrogas from coke and tar by circulating water in a modernized scrubber with new highperformance packings are shown.

Expressions for calculating the rate of turbulent particle migration for random and structured packings as well as modified Peclet numbers are presented. A distinctive feature of these expressions is the calculation based on the known hydraulic resistance of contact devices.

The article presents new models and methods for estimating the residual service life of an autonomous energy system, using the functional operational risk criterion (FOR). The purpose of the article is to demonstrate a new method of durability evaluation using the fuzzy logic and soft computing framework. Durability in the article is understood as a complex property directly adjacent to the complex property of system resilience, as understood in the Western practice of assessing and ensuring the reliability of technical systems. Due to the lack of reliable homogeneous statistics on system equipment failures and recoveries, triangular fuzzy estimates of failure and recovery intensities are used as fuzzy functions of time based on incomplete data and expert estimates. The FOR in the model is the possibility for the system availability ratio to be below the standard level. An example of the evaluation of the FOR and the residual service life of a redundant cold supply system of a special facility is considered. The transition from the paradigm of structural reliability to the paradigm of functional reliability based on the continuous degradation of the technological parameters of an autonomous energy system is considered. In this case, the FOR can no longer be evaluated by the criterion of a sudden failure, nor is it possible to build a Markov’s chain on discrete states of the technical system. Assuming this, it is appropriate to predict the defi ning functional parameters of a technical system as fuzzy functions of a general form and to estimate the residual service life of the technical system as a fuzzy random variable. Then the FOR is estimated as the possibility for the residual life of the technical system to be below its warranty period, as determined by the supplier of the equipment.