The article outlines the conceptual provisions for new approaches to assessing the technical condition of assets. Here, an approach through weight coeffi cients of the values of groups of parameters of functional equipment units is taken as the basis of expert defi nition. The methodology of determining weight coeffi cients based on the method of analyzing the hierarchies of T. Saaty is described in suffi cient detail. Based on the calculation of technical condition indices of individual functional units, in accordance with the solution of the problem of fi nding optimized values under fuzzy conditions and constraints, the integral indicator of equipment (equipment group) is determined by the minimum value. The author, in accordance with the method of assessing the technical condition of the main technological equipment and power transmission lines of electric power stations and electric grids and developing the optimal type, composition and cost of the technical impact on equipment (equipment group), develops concepts of the state of the equipment, correlating them with specifi c measures of technical impact. This allows us to objectify the assessment process and create an information base for making managerial decisions on the use of assets. The given example of calculation of the technical condition index allows to visually demonstrate the practical importance of the proposed approaches and methods for assessing production assets. The approaches defi ned in the article create an information and methodological basis for the transition from planned preventive repair of electrical power facilities equipment to condition-based repair. The article outlines the problem of comprehensive assessment of the technical and economic effi ciency of energy system assets, which includes numerous energy facilities. Formation of the methodological and technological basis of the production assets management system and ensuring its functioning determines the scientifi c value and innovative approach to solving the identifi ed problems mentioned in the article.

According to research, the total number of accidents on thermal networks which is related to exceeding the normative operation period has increased in the last two years. Obsolete networks lead to signifi cant heat losses. Energy effi ciency of heat supply can be increased with improvement of the reliability of thermal networks. When the federal law No. FZ-190 «On heat supply» was introduced, diagrams of heat supply of settlements began to be developed again. Calculation of heat supply reliability became an obligatory requirement. Methods of calculation of thermal networks reliability are provided in most detail in [1, 2]. The [2] technique suggests calculating reliability in the ZuluThermo software complex. The main basic parameter for calculation is the average failure rate. This value is theoretically the result of statistical investigations, and on practice uses the average value. Absence or lack of statistical information leads to a change in the actual reliability index, bringing it closer to the target value. A technique for collection and processing of failure statistics is suggested in [1]. However, for a number of reasons, there are certain diffi culties of receiving reliable basic data. Besides, as practice shows, data processing and assessment of the results also causes diffi culties. The results of the critical analysis of the listed techniques has shown that in order to receive calculations which are true it is necessary to have an up-to-date database on failures. What is new is that the principles of gathering the failure statistics and infl uence of real basic data on the actual reliability value are studied. It is revealed that formation of a database on failures in thermal networks will have a positive impact on promoting the reliability theory among specialists of the heat supplying organizations and operators, will minimize possible deviations of calculated reliability values, will allow to predict the development of heat supply systems in general and to prevent possible cascade damages of the vital power supply systems.

Thermal networks of Volzhsky, Volgograd region, are the object of research. The aim of this paper is to determine quantitative reliability indicators expressed as failure rates, time periods between failures and establishing a failure distribution law. Research of statistical data on failures of thermal networks have been conducted in the town of Volzhsky, Volgograd region, during the operation period from 2010 through 2012 after commissioning in 1970. All revealed failures led to interruption of heat supply and, accordingly, restoration of thermal networks. The article presents mathematical relationship between an assessment of reliability indicators in the form of failure rates and time periods between failures and the pipe diameter, the extent of thermal networks and the in-service time. The novelty of this article is that research of thermal networks’ reliability has been conducted in Volzhsky for the first time, and the results of these studies show actual numerical values of failure rates and provide an assessment of time periods between failures, analyzing its relationship with the diameter of pipes, the extent of thermal networks and the time of their operation. It has been established that failure rate is subject to the exponential law of distribution depending on the diameter and extent of pipes with parameters λ = 2,77·10^-3 (1/m), T = 362 m, and the operation time – with parameters λ = 35,31·10^-3 (1/h), T = 28 h. It is recommended to use the received estimates of reliability indicators during creation of modern thermal networks. The established system of maintenance and repair ensures reliable functioning of thermal networks with a confi dence level of 99%.

In accordance with the requirements of the current Electrical Code, all facilities receiving electricity from a centralized power supply system must be provided with the necessary reliability of electricity supply. This is particularly true for oil and gas facilities. Disconnecting these objects from the power supply network even for a short period of time can lead to accidents and bring great material and moral damage. Even if the equipment is not directly struck by a lightning, an electromagnetic pulse between the clouds and a distant lightning strike to the ground can still occur. The article presents a lightning protection device — the «Grozozaschita» installation, which is being tested at the Kiengop oil fi eld in the Udmurt Republic and installed on a standalone support in the area of CTS-6/0.4 kV, taking into account the confi guration of the 6 kV electric network at a 110 / 6 kV substation. A «Grozozaschita» installation is usually located on a hill at some remote distance from important infrastructure facilities. The operation principle of the installation is based on creation of an artifi cial lightning discharge zone. The problem with this setup is that it concentrates electric charges induced by various atmospheric phenomena. Therefore, during its operation, higher safety requirements must be observed. The designation of the main components of the lightning protection system and their functional purpose are described. During the operation of the device, no lightnings struck the equipment of the Kiengop oilfi eld and power transmission line, and there were no dangerous eff ects from lightning surges. Thus, protection of all electrical equipment has been enhanced, both against voltage drops and sudden voltage surge and pulses.

The article presents modern burner devices for power and industrial boilers that provide NOx emissions (when burning natural gas — 125 mg/m3, when burning fuel oil — 250 mg/m3). The burners are equipped with modern ignition safety devices and injectors. There are also new burners for combustion of blast furnace, coke oven and natural gas. Combustion of gases with diff erent properties causes certain diffi culties associated with providing operational parameters of power plants. Diff erences in the characteristics of combustible fuels also determine the diff erences in the course of combustion processes, emission characteristics of the fl are, and volumes of combustion products. The article gives successful examples of the operation of combined burners. Also considered in the article are the peculiarities of the organization of the furnace process for co-incineration of blast furnace gas, coke oven gas and natural gas in boiler furnaces from 100 to 500 t/h. The article provides guidelines on combustion of low-calorifi c by-products of industrial enterprises (blast furnace gas, coke oven gas, etc.). An important factor for solving environmental problems is the need to recycle liquid and gaseous wastes of powerful industrial enterprises. We have developed special ovens for neutralizing industrial effl uents and various gases. The main technical solutions for the organization of combustion of gaseous and liquid wastes are given in the article. Two variants of furnace arrangements (vertical and horizontal) are presented. A furnace with a burner for burning water-coal suspension is also of considerable interest. Materials are presented on new developments of various types of heat generators: with internal refractory and fi reproof lining and those completely made of metal (air-cooled, internal fl ame tube made of steel Х18Н9Т, outer housing — steel 20). Special combustion chambers can be used to neutralize gaseous and liquid wastes.

At present, plate heat exchangers (PHE) are used everywhere, starting from the housing and utilities sector to nuclear power. However, there are no standard methods for heat and hydraulic calculations for plate heat exchangers. That is why the manufacturer uses special software to select heat exchangers for a particular task. And often even engineers have no access to the code and algorithms of these programs. Thus, correctness of such calculations is questionable, especially for the unusual operating modes of heat exchangers. To solve these issues, it is necessary to carry out thermal-hydraulic tests of plate heat exchangers from diff erent companies, with subsequent comparative analysis and identifi cation of possible diffi culties in thermal-hydraulic calculations. In the course of this work, we proposed a test procedure for plate heat exchangers with the same fl ow rate along the circuits, simplifying the subsequent processing of the experimental data. This method is applicable for PHEs with an equal number of channels on their hot and cold sides. Using this method, 13 plate heat exchangers were tested at the KS10606 Complex test facility of JSC “NPO CKTI”. The results of experiments and analysis of the data provided by the PHE manufacturers showed no signifi cant diff erence in the thermal-hydraulic characteristics of plates of the same size of diff erent manufacturers. Presence of breathing eff ect in PHEs was confi rmed. Breathing eff ect is caused by elastic deformation of heat transfer plates in the presence of pressure diff erence between hot and cold sides of PHE. It is shown that this eff ect can signifi cantly aff ect the hydraulic resistance. The maximum observed diff erence between the hydraulic resistance coeffi cients in circuits with a lower and higher pressure was about 3.5 times. However, this eff ect is not typical of all plate heat exchangers.

In accordance with NP-096-15 [1], management of equipment and pipelines resources at the stages of design, operation and decommissioning should be based on the evaluation of the technical condition and residual life; identifi cation of the dominant (controlling) mechanisms of aging, degradation and damage of equipment and pipelines of nuclear power plants (NPP); the constant improvement of monitoring processes of aging, degradation and damage of equipment and pipelines of nuclear power plants. Despite the progress in computer development in recent decades, its capabilities are still insuffi cient to solve equations of hydrodynamics when high Re numbers are of practical interest (solution instability: arbitrarily small perturbation radically alters the stability of the solution of the Navier-Stokes equations). Challenges remain in the verifi cation of CFD codes. Due to the complex spatial confi guration of diff erent functional purpose piping systems of NPPs, as well as the specifi cs of the hydro-elastic interaction of the fl ow and tubing, calculation methods to evaluate the dynamic stress-strain state can be selected only based on the results of experimental measurements of vibration parameters of pipelines. The vibration parameters of the pipelines are the vibrational acceleration, velocity and displacement. Vibration of piping from the point of view of resource is classifi ed as high cycle fatigue, which, due to its specifi cs, requires adopting conservative approaches in substantiation of vibration strength of pipelines. As the pipelines are operating within the elastic deformation, the strength test with time-dependent load can in some cases be replaced with a quasistatic calculation. A numerical experiment illustrates the application of the quasistatic approach that gives satisfactory results. Substantiated application of the quasistatic approach is based on the analysis of the spectral density of the pipeline vibration at diff erent points of measurement and can be eff ectively used to assess vibrostresses, fracture toughness and substantiation of vibration strength of NPP pipelines.

Estimation is given of thermodynamic efficiency of flow diagrams for small scale power plants with a working substance of fluoroorganic composition. A review of existing organic Rankine cycle (ORC) 4 technologies with working media other than those of the fluorocarbon composition has been given. As an object of comparison and replacement by a nonaqueous power plant, a small scale biomass fuelled power plant has been chosen using solid bark waste biomass as a fuel. This plant design is based on the traditional water-steam Rankine cycle. The calculated analysis of thermodynamic efficiency of multicircuit flow diagrams, with staged heat utilization circuits, as well as consecutive heat transfer from one circuit to another, proposed as an alternative to the traditional cycle, has been provided. The efficiency of steam-turbine cycles of the proposed arrangement has been analyzed for octafluoropropane (C₃F₈) and decafluorobutane (C₄F₁₀). The calculation of cycles and processes for new power generating units involved using experimentally substantiated state equations obtained by the authors earlier. The influence on internal cycle efficiency of new small scale power generating units depending on initial live steam pressure at turbine inlet and condensing temperature has been studied. A significant increase of thermal efficiency is noticed for the staged heat utilization arrangement, compared to the water-steam cycle. A number of technological and design advantages have been noted that can be achieved through applying working fluids of the fluorocarbon composition as the working media for small scale thermal power plants.

The article is devoted to the problem of low temperature corrosion of heating surfaces occurring in the non-heating season in heat exchangers of gas turbine cogeneration power plant when working on 150/70 heating system temperature chart. An overview is presented of the existing methods of eliminating such corrosion, including the analysis of their drawbacks. A new approach to ensuring the required temperature level of water in the heat exchangers is proposed. Based on the proposed approach, design solutions are developed and proposed aimed at eliminating the problem of low temperature corrosion of the heating surfaces during the non-heating season. The developed solutions are based on the arrangement of loop pre-heating of the network water where the reverse network water is heated to the minimum allowable temperature at the inlet to the gas-water heat exchanger (GWHE). Two options of thermal circuits with a closed circuit coolant circulation are proposed. The circuits differ in the method of heating the heating medium flowing in WTO: the first one operates by burning fuels in boilers, and the second one by using the heat of the exhaust gas entering the dedicated heating surface of GWHE. The advantage of the first option is the ability to disable the loop pre-heating at low outdoor temperatures when the temperature of the water at the inlet to GWHE exceeds the allowed minimum which reduces the annual cost of electricity for own needs. The advantage of the second option of the thermal circuit is a reduction in energy costs of the circulation pump operation by reducing the flow of coolant circulating in a closed circuit. The calculations of the proposed thermal schemes allowed to conclude that the proposed methods of closed loop pre-heating of the network water provide acceptable water temperature in GWHE with consideration of CHP operation modes throughout the year and help to prevent low-temperature corrosion of heat exchangers heating surfaces.

The article presents the results of research on the eff ect of damage rate of steam turbine technological subsystems equipment on the operation of a power plant. It was revealed on the basis of analysis of reliability indicators of power units that malfunctions of steam turbine unit (STU) equipment accounted for 25 – 30 % of the total number of failures. The article presents the results of the malfunction analysis for the equipment of various STU technological subsystems operating in the power units and at cross-links power stations and leading to the turbine unit shutdown (failure). It is shown that critical equipment causing turbine unit shutdown in 70 or more percent of cases is represented by the equipment of three technological subsystems: condenser unit, oil supply subsystem and feed water subsystem. Based on the analysis results for operational documentation obtained at the Ural-Siberian region power plants for more than 300 power units with capacity of 200 to 800 MW, the article presents data on the eff ect of equipment failures at various technological subsystems on unplanned shutdowns of steam turbines. It also studies the basic malfunctions of the most critical equipment (that is of condenser, ejector, gland steam heaters, feedwater and condensate pumps, oil coolers, etc.) which can result both in its failure and in turbine unit functional shutdown. Statistical data is presented on the distribution of the causes of damage to condensers, ejectors, feedwater and condensate pumps and oil system equipment. Data presented in the article can be used to develop modules of technical condition monitoring and diagnostics as well as failure preventing measures for steam turbine technological subsystems equipment.

The article covers approaches to building the mathematical models of cogeneration steam turbine units. The objective of this work is the development, justifi cation and practical implementation of methods of mathematical modeling of cogeneration steam turbines for solving research problems and improving the energy effi ciency of the CHP. The use of normative characteristics to solve these tasks, which require the calculation of variable modes, in most cases turns out to be unjustifi ed, due to a number of their signifi cant shortcomings. It is shown that the application of the developed mathematical models based on experimentally determined fl ow and power characteristics allows to solve various practical tasks arising during operation. We have given an example of constructing a computational mathematical model of a T-50-12.8 type turbine. The method of construction of this model is described, which consists of a large number of nonlinear equations (over 50), and an enlarged block diagram of calculations for this turbine (using the modernized Newton method with a step change of the iteration process in several variables) is provided. The method of calculating an arbitrary turbine compartment or a stage using some experimental fl ow and power characteristics is given as part of the general algorithm. A method for calculating the LPH-1 regenerative heater is also given as an example. It is shown how similar models of other equipment can be developed on the basis of the described mathematical model. The article provides examples of the use of mathematical models of turbines for solving problems of determining the most economical and safe operating modes and preventing ineffi cient solutions. The obtained results allow to determine the optimal operating modes of real CHP equipment and calculating their absolute and comparative energy efficiency.

In the Russian energy sector, the process of modernization of turbine units with a capacity of 100÷800 MW is underway aimed at increasing their capacity and improving the efficiency of the wheelspace of turbine units. The modernization focuses on the design of the flowing part of turbines, which allows to obtain a significant, but not a complete, modernization effect, since the regeneration scheme and its equipment remain the same. In the best case, old equipment is replaced with newly manufactured one which was still designed in the 1970s – 1980s. Improvement of thermal schemes of power units of all types is one of the priority tasks for improving operational and technical and economic indicators of TPPs. The regeneration scheme increases the efficiency of the cycle by 12÷14%; therefore, its modernization, provision of new highly-efficient and reliable equipment, a reduction in the underheating of the main condensate and feed water, and the hydraulic resistance of their paths can have a significant positive effect and help to save fuel. The article presents the shortcomings of the existing regeneration schemes, summarizes the selection criteria and gives options for regeneration schemes for 100÷800 MW turbine units. Different solutions are proposed, both in terms of the composition of the equipment and the structure of the regeneration scheme. A comprehensive approach has been implemented in the development and modernization of turbine regeneration schemes. The designs of low and high-pressure heaters have been developed with reference to the adopted regeneration scheme. The accumulated experience of introducing mixing heaters and using no-deaerator thermal circuits is generalized. The proposed solutions for the modernization of the regeneration scheme, the composition and type of equipment can be implemented for turbine units of various capacities.