Operation Of Supply Systems Research Articles

Анализ технологических направлений электрификации объектов добычи углеводородов на слабоосвоенных территориях.

The article considers modern technological directions for the electrification of hydrocarbon production facilities in the poorly developed or hard-to-reach territories of the Arctic, the Far North or offshore fields, due to the remoteness of the Arctic and Far Eastern regions from existing large energy hubs, which makes it practically impossible to use a unified energy system of RF (UES RF) as the main source of electricity for needs of the oil and gas industry. The conditions of the UES RF using necessitates the additional generation sources for oil and gas companies and the solution of related issues of economic and environmental efficiency of technological projects for the electrification of hydrocarbon production facilities in hard-to-reach and poorly developed territories. The study performed a cluster analysis of literary sources in order to determine the current trends in the electrification and power supply of the oil and gas industry. An assessment of the conditions for the application of modern technological directions for the electrification of hydrocarbon production facilities in the poorly developed and hard-to-reach territories of Russia is presented. The system analysis covers electrification options using gas-fired generators; based on the integration of renewable energy sources and their combination with traditional types of electricity supply; using complexes of unified energy networks for several offshore production facilities and additional energy centers. The study of technological directions for the electrification of hydrocarbon production facilities in poorly developed territories is the basis for further practical application of the results of the analysis in the field of pre-project planning and evaluation of proposed technological solutions based on the rational choice of a power source for remote fields, taking into account the optimal composition of equipment and the location of elements of power supply systems, construction schedule and indicators of the cost of construction and operation of energy supply systems.

АНАЛИЗ ВОЛНОВЫХ ПРОЦЕССОВ В ТЯГОВОЙ СЕТИ ПЕРЕМЕННОГО ТОКА НА ОСНОВЕ ИМИТАЦИОННОГО МОДЕЛИРОВАНИЯ

Wave processes negatively affect energy losses and lead to appearance of emergency situations in traction power supply system. In order to increase energy efficiency, to improve quality of energy and to provide uninterrupted operation of power supply systems there is a need in a comprehensive approach to the analysis of wave processes in the system that includes not only the traction power system but also power transmission lines and electric motive power. A model created in the SimInTech environment allows carrying out studies at multivariate modes of operation of the alternating current traction power supply system with traction load with the consideration for wave processes.

MODERNIZATION OF WATER SUPPLY SYSTEMS FROM SURFACE SOURCES

Surface water bodies, which are sources of drinking water supply, receive a significant amount of pollution from wastewater. This negatively affects the ecological condition of water resources and poses a threat to the health and sanitary well-being of the population. The main pollutants of surface sources are: sewage of economic-fecal and industrial sewage, which contain organic pollutants, surfactants, heavy metal ions; oil products coming from industrial sites and urban areas; effluents from livestock farms and storage ponds of production waste; washing of mineral fertilizers and pesticides from agricultural lands. Adjustment of surface springs additionally affects the deterioration of water quality in them. Therefore, existing water treatment technologies may not always provide the required degree of drinking water purification. According to monitoring studies, more than 38% of water samples taken at centralized water supply facilities did not meet regulatory requirements. This situation encourages the search for ways that would create conditions for more efficient operation of water supply systems. Modernization of existing water supply facilities and application of new water treatment technologies can help solve the problem. The article illustrates constructive schemes of shore and channel water intake and treatment facilities, the use of which makes it possible to reduce the dirt retention load on the main treatment facilities, increase the reliability of fish fry protection and improve the ecological condition of reservoirs at water intake sites. For effective removal of organic matter at water treatment plants, it is advisable to use bioreactors and contact-clarifying filters. Such solutions allow not only to increase the productivity of the water treatment plant, but also significantly reduce its construction cost, simplify the operation of facilities and reduce annual operating costs.

DETERMINATION OF TECHNOGENIC RISKS IN TRANSITIONAL STATES DURING OPERATION OF WATER TREATMENT SYSTEMS IN HEAT ENERGY

Introduction. Currently, the most important issues in the national economy are the issues of continuous, reliable and safe operation of circulating water supply systems, namely power units of thermal power plants and thermal power plants of industrial enterprises. Faultless and reliable operation of water supply systems ensures the normal operation of social and industrial enterprises, as well as the safe operation of fire protection systems, which can be disrupted by stopping the supply of quality products to the consumer. In Ukraine and abroad, this issue is devoted to many scientific papers on the assessment, calculation and management of man-made risks, the calculation and management of risks in water treatment systems in heat and energy. But the impact of these risks on environmental safety is not covered, while the issue is of great economic importance. However, the influence of these risks on environmental protection is not covered, while the problem is of great economic importance. There is no general methodological approach that considers the diversity of water treatment systems and their design solutions. There is no clear ranking of objects to be protected by risk analysis, and there is no analysis of the effects acting on them.Purpose and methods. The purpose of the work is to determine the risks associated with the patterns of the probability of failure of units, the patterns of transition from state to state and the risks associated with changes in patterns when replacing the blocks of the water treatment system or its elements. To study the probability of risks as a result of failures for the entire period of operation of the water treatment system in the heating industry, a structural and functional block diagram of the water treatment system is built. To obtain numerical data on the failure probability at any time, the failure probability curve was approximated by the curves of the law of normal distribution (Gaussian curves).Results and discussion. Studies have shown that the minimum risk is proportional to the minimum probability of failure. Then it will be fair to say that to minimize the risk, it is necessary to reduce the failure probability function on the part of the failure curve that corresponds to the operating state of the unit or element, that is on the plot or in the normal operation. To calculate the minimum probability of risk, it is necessary to determine the minimum of this function. Since failure is a function of many variables, thus Rfail = f (x, y, z) → 0. It is also established that for most water treatment systems at any time of operation it is possible to determine the risks associated with the regularities of failure probabilities of units, with regularities the transition of the system from state to state and the risks associated with changes in the above patterns when replacing the blocks of the water treatment system or its elements.Conclusions. As a result of the conducted researches, it is received that at long enough work of water treatment system it is necessary to establish in it a probabilistic constant mode of transition from a condition to a condition according to the scheme "working condition of all blocks - failure of one or several blocks - repair - working condition of all blocks". The probabilities of the sequence and duration of these events are determinable, which makes it possible on the one hand to assess the risks arising from the operation and to determine a management strategy to minimize these risks. The probability of failure rate intensity and possible changes in this probability during the operation of the water treatment system depending on the time interval on the failure curve on which the operation of this system is considered. Determining this probability makes it possible to predict risks throughout the periods of operation of systems and take measures to minimize them.

On the need of addressing voltage sag and short interruption concerns in power supply system design and operation

Voltage sags and interruptions are generally caused by faults on power supply systems. Voltage sags and interruptions significantly reduce electric power quality and can result to equipment failures, control malfunctions, and other technical and financial losses. In our research, we proof the need of addressing voltage sag and short interruption concerns in power supply systems to make them safer and more cost-effective. We describe certain characteristics of voltage sags and short interruptions, determine what causes them, how they affect various types of equipment, and how to improve design and operation of power supply systems taking into account protection from voltage sags and short interruptions.

Analysis of the concepts of building microgrids containing distributed generation objects

In this article, the authors consider the materials of research on the construction and operation of intelligent power supply systems with a nominal voltage of up to 1000 V, containing distributed generation facilities. The author’s approach to the construction of microgrids based on multi-contact switching systems is proposed. The similarities and differences of the presented concepts are determined. The main problematic issues that arise in the process of implementing projects for the construction of microgrids and the management of electric power modes of operation are formulated. The ways of solving the problems related to the management of the modes of operation of microgrids are proposed.

ЭКОНОМИЧЕСКАЯ ЭФФЕКТИВНОСТЬ БЕСКОНТАКТНОГО АВТОМАТИЧЕСКОГО РЕГУЛИРОВАНИЯ НАПРЯЖЕНИЯ ТИРИСТОРНО-РЕАКТОРНЫМ ПЕРЕКЛЮЧАЮЩИМ УСТРОЙСТВОМ В СИСТЕМЕ ТЯГОВОГО ЭЛЕКТРОСНАБЖЕНИЯ ПОСТОЯННОГО ТОКА

The paper presents results of analysis of disadvantages of contactless automatic voltage regulation (CAVR) system with a reactor switching device (RSD) that is used on direct current electrified railways. It also shows direction of its improvement. The authors have considered a functional scheme of the closed CAVR system of a converter unit with a thyristor-reactor switching device (TRSD) and a TRSNP-12500/10 converter transformer. They have also carried out an engineering and economical comparison of two modes of traction power supply system (TPSS) operation: without application of voltage regulation devices on traction substations with no-load voltage of 3500 V and with application of voltage regulation devices by the CAVR system at stabilization of voltage on levels of 3500, 3600 and 3700 V with various variants of switching devices. As a result, the authors have determined that the use of the CAVR system with the TRSD is economically efficient.

Collision Mechanism and Deposition Characteristics of Particles on the Catenary Insulator Surface

To solve the problem of contamination flashover of a catenary insulator in an electrified railway, the collision mechanism and deposition characteristics of contamination particles on the insulator surface should be studied to ensure the safe operation of traction power supply systems. This research used horizontal and oblique cantilever insulators as objects, and established the collision model between particles and insulator surface under different arrangements. The deposition conditions of particles on the insulator surface were obtained, and the simulation model of insulator contamination accumulation was established by using the Euler two-phase flow. The difference of contamination deposition characteristics between horizontal and oblique cantilever insulators was analyzed with the volume fraction of contamination particles as the characterization parameter. By comparing the cantilever insulator with the positive feeder insulator, this study analyzed the influence of shed structure on the contamination deposition characteristics. Results show that the installation method of an insulator has an impact on the contamination deposition on the insulator surface. When particle size and wind velocity are fixed, the degree of contamination accumulation on the surface of the oblique cantilever insulator is constantly higher than that of the horizontal cantilever insulator. The insulator shed structure also has a certain effect on the contamination deposition on the insulator surface. For the cantilever insulator, the degree of contamination accumulation of the windward side is higher than that of the leeward side. However, for the positive feeder insulator, the degree of contamination accumulation of the windward side is consistently less than that of the leeward side. Measures to deal with contamination flashover of catenary insulator are proposed.

Истоки и потоки

Истоки и потоки

Improving quality of ac electric power supply of autonomous power sources using in agriculture

Autonomous AC electricity supply systems are now widely introduced in agriculture. As the experience of operation of these electricity supply systems has shown, their various properties, determined largely by the type of voltage regulators and sensors used, do not always fully meet the constantly growing requirements for the quality of electricity. Further improvement of voltage regulation systems, and, consequently, the quality of electricity, is associated with the use of technology in them that can implement optimal control laws.

Optimal Operation of Heat Supply Systems with Piping Network by a Mixed-Integer Nonlinear Model

Optimal Operation of Heat Supply Systems with Piping Network by a Mixed-Integer Nonlinear Model

МАТЕМАТИЧНЕ МОДЕЛЮВАННЯ РЕЖИМІВ ПЕРЕМИКАННЯ НАРЕЗЕРВНЕ ЖИВЛЕННЯ АСИНХРОННИХ ДВИГУНІВ

Purpose. Simulation of transient and steady state modes of induction motor for analysis of processes of switching to backup power by means of mathematical model. Method. The methods of linear algebra, numerical optimization methods, methods of modeling and analysis of established and transient modes are used. Results. A mathematical model is proposed in the form of a circuit diagram of an induction motor with a double-circuit rotor, which allows to take into account the effect of displacement of current and saturation of the steel of the motor magnetic circuit. A technique for determining the parameters of the induction circuit of an induction motor is proposed, which allowsto improve the accuracy of modeling in steady state and transient modes. The mathematical model isreduced to a three-phase coordinate system a, b, c. The results of mathematical modeling have shown that the induction motor asynchronous activation, which takes place in the case of automatic input of the reserve and in other cases, leads to dangerous values of the shock currents and shock torque of the induction motor. Shock currents can also be dangerous to other power supply equipment. Thus, induction motors, when the rotor's own field has not yet gone out, require synchronization before being connected to the network, as well as synchronous machines. Scientific novelty. The mathematical model of the asynchronous motor was improved, taking into account the displacement of current and saturation of the magnetic circuit, the method of determining the parameters of the mathematical model was improved, which allowed to increase the accuracy of the simulation and the reliability of the simulation results. The modes of switching to backup power are simulated and the values of shock current and shock torque of the engine are obtained. Practical meaning. The mathematical model of an induction motor allows to analyze the behavior of induction motors in interaction in the power supply system and to identify the dangerous states of asynchronous motors. The proposed model allows to improve the accuracy of determination of the limits of dangerous states and to increase the reliability of operation of induction motors and power supply systems

Integrated approach to assessment of impact of beyond-design modes on operation of steam supply systems

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.

Organizational operation model of water supply agricultural organizations

Water supply for agricultural organizations in sufficient quantity and quality with minimum costs is the foundation of efficient production and raw materials for some industries, as well as the basis for water management.This article discusses the features and operation problems in water supply systems, surpluses on the balance of agricultural organizations. Science-based approaches to optimize the operation of water supply systems are presented in the article.For planning and control of exploitation of water supply systems in agricultural organizations it is recommended to group all repair and maintenance works into stages. These stages vary in purpose, scope and deadlines. One of four designed organizational operating models must be used for delegation of authorities.

Reducing water shortage crisis through rainwater reuse: lessons learned from ancient toward integrated technology

The quantity of freshwater available per person in the world has been proceeded to decrease due to a combination of factors, including population increase, water pollution, inadequate planning and management of transboundary water, and inefficient operation of water supply and distribution systems. There is a direct water source to cease increasing potential for water scarcity, crisis and associated conflicts around the world in the future called rainwater harvesting that is an ancient technique enjoying a revival in popularity due to the inherent quality of rainwater and interest in reducing consumption of treated water. Rainwater harvesting is included as an innovative site design strategy to minimise runoff based on LID practices. The present study on literature attempts to offer a comprehensive account of the above issues and also some important guidelines for advancing research in this direction. Assessments of past, present and future statuses of the world's water are reviewed.

Selection of filter parameters of Individual water supply systems

The paper is devoted to the problem of optimal design, construction and operation of water supply systems and their elements. The key element of the system is a water well. The quality of its design and construction determines the operation of the water intake as a whole. Disadvantages in the construction of a well lead to disruption of the entire water supply system of a particular object. The paper proposed a methodology for selecting the optimal diameter and length of the well filter of a water well. Based on the methodology, an example of filter parameters selection for hydrogeological conditions of the city of Kursk is given. The above calculation showed that the use of the entrance velocity criterion in the design of wells can significantly reduce the cost of well construction while ensuring the design flow rate and allowable lowering of the water level. The cost of the filter, depending on the well design, is 20-30% of the total price for its construction. The most important filter parameters affecting the cost of a well are its length and diameter. Justifying the minimum diameter of the filter that ensures the designed water intake and allowable dewatering can significantly reduce the cost of the well, taking into account the fact that modern pumping equipment allows the use of columns of small diameter above the filter.

Problems of energy efficiency of heat supply systems

The main task of energy-efficient heat supply is to ensure full compliance between the produced and consumed thermal power, subject to a minimum of reduced costs. To achieve this goal, various methods of central and local regulation are applied. Analysis of the thermal schemes of some cities in Russia showed that most of the heat sources of centralized heat supply systems are not able to support the design hightemperature graphs with central regulation. Therefore, the area of centralized qualitative method of regulation of heat load has decreased substantially. A perspective direction for the further development of heat supply systems is to appeal to the experience of foreign countries, i.e. the use of qualitative-quantitative and quantitative methods of central regulation and low-temperature heat supply. There is also an acute problem of the complete use of heat by consumers, since overstating of the temperature of the return water substantially reduces the efficiency of heat sources. A new formula has been obtained which makes it possible to predict the temperature of the return network water in variable operating modes of heating points. The resulting formula can be used to set up programmable regulators and will allow correcting irrational modes of operation of heat supply systems.

ACCIDENT ANALYSIS OF LOW PRESSURE GAS DISTRIBUTION SYSTEMS

In terms of safety, gas supply represents a highly important area of science and engineering. On the one hand, gas is a very convenient primary energy source for consumers. On the other hand, gas can be extremely dangerous for life and health of people, if strict requirements to design, construction and operation of gas supply systems are not complied with. The article reviews an accident that occurred in a small Polish city in 2010. We analyzed data from the Prosecutor’s Office and relevant publications and questioned workers of the gas supply company. The article describes how an unlucky train of events resulted in a tragedy. The main circumstances were an unacceptable change in the gas distribution plant equipment and violation of operating rules, which resulted in an unauthorized pressure increase in a district network and internal systems designed for low pressure. We analyzed follow-up technical and administrative measures taken regarding the Polish gas supply system and compared some peculiarities of Polish and Russian gas technologies. The main purpose of the analysis is to prevent such accidents in future.

Informacionno-analiticheskaja tehnologija optimalnogo upravlenija ustojchivym razvitiem i funkcionirovaniem sistem vodosnabzhenija

Informacionno-analiticheskaja tehnologija optimalnogo upravlenija ustojchivym razvitiem i funkcionirovaniem sistem vodosnabzhenija

SELECTION OF PARAMETERS OF THE FILTER AT DESIGN OF WATER WELLS

The article is devoted to present the problem of optimal design, construction and operation of water supply systems and their elements. A key element of the downhole water intake is water intake well. The quality of its design and construction determines the operation of the water intake as a whole. Disadvantages in the design of the well lead to disruption of the entire water supply system of a particular facility. The choice of a filter suitable for specific geological conditions of the well and ensuring a long operating time is a very complex technical task. When calculating the filters, it is necessary to determine their length, diameter, duty cycle and the size of the through holes. These filter parameters are determined so that the input speed does not exceed the permissible speed for the filter, i.e. V ф ≤ V доп. . The article suggests a method for selecting the optimal diameter and length of a downhole filter of a water intake well. Based on the methodology, an example is given of the selection of filter parameters for hydro-geological conditions in the city of Kursk. The calculation showed that application of the input speed criterion for well design allows to significantly reduce the cost of wells while ensuring the design production rate and permissible level reduction.