394 research outputs found

    Threshold of microvascular occlusion: injury size defines the thrombosis scenario

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    Damage to the blood vessel triggers formation of a hemostatic plug, which is meant to prevent bleeding, yet the same phenomenon may result in a total blockade of a blood vessel by a thrombus, causing severe medical conditions. Here, we show that the physical interplay between platelet adhesion and hemodynamics in a microchannel manifests in a critical threshold behavior of a growing thrombus. Depending on the size of injury, two distinct dynamic pathways of thrombosis were found: the formation of a nonocclusive plug, if injury length does not exceed the critical value, and the total occlusion of the vessel by the thrombus otherwise. We develop a mathematical model that demonstrates that switching between these regimes occurs as a result of a saddle-node bifurcation. Our study reveals the mechanism of self-regulation of thrombosis in blood microvessels and explains experimentally observed distinctions between thrombi of different physical etiology. This also can be useful for the design of platelet-aggregation-inspired engineering solutions.Comment: 7 pages, 5 figures + Supplementary informatio

    Blood flow controls coagulation onset via the positive feedback of factor VII activation by factor Xa

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    <p>Abstract</p> <p>Background</p> <p>Blood coagulation is a complex network of biochemical reactions, which is peculiar in that it is time- and space-dependent, and has to function in the presence of rapid flow. Recent experimental reports suggest that flow plays a significant role in its regulation. The objective of this study was to use systems biology techniques to investigate this regulation and to identify mechanisms creating a flow-dependent switch in the coagulation onset.</p> <p>Results</p> <p>Using a detailed mechanism-driven model of tissue factor (TF)-initiated thrombus formation in a two-dimensional channel we demonstrate that blood flow can regulate clotting onset in the model in a threshold-like manner, in agreement with existing experimental evidence. Sensitivity analysis reveals that this is achieved due to a combination of the positive feedback of TF-bound factor VII activation by activated factor X (Xa) and effective removal of factor Xa by flow from the activating patch depriving the feedback of "ignition". The level of this trigger (i.e. coagulation sensitivity to flow) is controlled by the activity of tissue factor pathway inhibitor.</p> <p>Conclusions</p> <p>This mechanism explains the difference between red and white thrombi observed <it>in vivo </it>at different shear rates. It can be speculated that this is a special switch protecting vascular system from uncontrolled formation and spreading of active coagulation factors in vessels with rapidly flowing blood.</p

    Continuous Modeling of Arterial Platelet Thrombus Formation Using a Spatial Adsorption Equation

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    In this study, we considered a continuous model of platelet thrombus growth in an arteriole. A special model describing the adhesion of platelets in terms of their concentration was derived. The applications of the derived model are not restricted to only describing arterial platelet thrombus formation; the model can also be applied to other similar adhesion processes. The model reproduces an auto-wave solution in the one-dimensional case; in the two-dimensional case, in which the surrounding flow is taken into account, the typical torch- like thrombus is reproduced. The thrombus shape and the growth velocity are determined by the model parameters. We demonstrate that the model captures the main properties of the thrombus growth behavior and provides us a better understanding of which mechanisms are important in the mechanical nature of the arterial thrombus growth

    Th1 and Th17 Cells in Tuberculosis: Protection, Pathology, and Biomarkers

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    Simulation of the Electrical-Technical Complex of the Power Transmission Line of DC in the MATLAB Program Environment

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    Одним ΠΈΠ· основных Π½Π°ΠΏΡ€Π°Π²Π»Π΅Π½ΠΈΠΉ развития элСктроэнСргСтичСских систСм являСтся Π²Π½Π΅Π΄Ρ€Π΅Π½ΠΈΠ΅ устройств ΠΈ Ρ‚Π΅Ρ…Π½ΠΎΠ»ΠΎΠ³ΠΈΠΉ Π½Π° Π±Π°Π·Π΅ силовых ΠΏΠΎΠ»ΡƒΠΏΡ€ΠΎΠ²ΠΎΠ΄Π½ΠΈΠΊΠΎΠ²Ρ‹Ρ… ΠΊΠ»ΡŽΡ‡Π΅ΠΉ (HVDC (High Voltage Direct Current) Ρ‚Π΅Ρ…Π½ΠΎΠ»ΠΎΠ³ΠΈΠΉ), Π² частности вставок постоянного Ρ‚ΠΎΠΊΠ° Π½Π° Π±Π°Π·Π΅ прСобразоватСля источника напряТСния (VSC). VSC-HVDC ΠΈΡΠΏΠΎΠ»ΡŒΠ·ΡƒΡŽΡ‚ΡΡ для Ρ€Π΅ΡˆΠ΅Π½ΠΈΡ Ρ‚Π°ΠΊΠΈΡ… Π·Π°Π΄Π°Ρ‡, ΠΊΠ°ΠΊ соСдинСниС нСсинхронных элСктричСских сСтСй Ρ€Π°Π·Π»ΠΈΡ‡Π½Ρ‹Ρ… частот, ΠΏΠ΅Ρ€Π΅Π΄Π°Ρ‡Π° элСктроэнСргии, ΠΏΠΎΠ²Ρ‹ΡˆΠ΅Π½ΠΈΠ΅ локальной ΠΈ систСмной управляСмости элСктроэнСргСтичСской систСмы, ΠΏΠΎΠ²Ρ‹ΡˆΠ΅Π½ΠΈΠ΅ пропускной способности элСмСнтов сСти, содСрТащих «слабыС» связи. Благодаря высокой стСпСни управляСмости ΠΏΡ€Π΅ΠΎΠ±Ρ€Π°Π·ΠΎΠ²Π°Ρ‚Π΅Π»Π΅ΠΉ источника напряТСния (VSC) Π² основном рассматриваСтся Ρ€Π°Π±ΠΎΡ‚Π° HVDC. Однако Π²Π½Π΅Π΄Ρ€Π΅Π½ΠΈΠ΅ ΠΈ эксплуатация VSC-HVDC ΠΎΠΏΡ€Π΅Π΄Π΅Π»ΡΡŽΡ‚ Π½Π΅ΠΎΠ±Ρ…ΠΎΠ΄ΠΈΠΌΠΎΡΡ‚ΡŒ Π² ΠΏΡ€ΠΎΠ²Π΅Π΄Π΅Π½ΠΈΠΈ ΡˆΠΈΡ€ΠΎΠΊΠΎΠ³ΠΎ спСктра Π°Π½Π°Π»ΠΈΠ·Π° ΠΈ исслСдований, ΠΊΠΎΡ‚ΠΎΡ€Ρ‹Π΅ ΠΌΠΎΠΆΠ½ΠΎ провСсти Ρ‚ΠΎΠ»ΡŒΠΊΠΎ с ΠΏΠΎΠΌΠΎΡ‰ΡŒΡŽ матСматичСского модСлирования. ΠŸΠΎΡΡ‚ΠΎΠΌΡƒ Ρ†Π΅Π»ΡŒΡŽ Ρ€Π°Π±ΠΎΡ‚Ρ‹ являСтся: Π°Π½Π°Π»ΠΈΠ· повСдСния систСмы ΠΏΠ΅Ρ€Π΅Π΄Π°Ρ‡ΠΈ HVDC Π½Π° основС VSC с использованиСм Ρ€Π°Π·Π»ΠΈΡ‡Π½Ρ‹Ρ… Ρ€Π΅ΠΆΠΈΠΌΠΎΠ² управлСния ΠΏΡƒΡ‚Π΅ΠΌ модСлирования Π² ΠΏΡ€ΠΎΠ³Ρ€Π°ΠΌΠΌΠ½ΠΎΠΉ срСдС MATLAB. One of the main directions of the development of electric power systems is the introduction of devices and technologies based on high-power semiconductor switches (HVDC (High Voltage Direct Current) technologies; one of the elements of this technology is direct current link on the basis of voltage source converter (VSC). VSC-HVDC are used for tasks such as connecting asynchronous power grids for various frequencies, transmission of electricity, improve local and systemic handling of electric power system, increasing the capacity of network elements that contains a β€œweak” connection. Due to the high degree of controllability of voltage source converters (VSCs), it is mainly addressed in the recent literature on HVDC operation. However, the implementation and operation of VSC-HVDC determines the need for a wide range of analysis and research that can only be done with the help of mathematical modeling. therefore, the purpose of the work is: to analyze the behavior of the HVDC transmission system based on VSC using various control modes by modeling in the MATLAB software environmen

    MODEL OF GEOMEDIA CONTAINING DEFECTS: COLLECTIVE EFFECTS OF DEFECTS EVOLUTION DURING FORMATION OF POTENTIAL EARTHQUAKE FOCI

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    This paper describes the statistical thermo-dynamical evolution of an ensemble of defects in the geomedium in the field of externally applied stresses. The authors introduce β€˜tensor structural’ variables associated with two specific types of defects, fractures and localized shear faults (Fig. 1). Based on the procedure for averaging of the structural variables by statistical ensembles of defects, a self-consistency equation is developed; it determines the dependence of the macroscopic tensor of defects-induced strain on values of external stresses, the original pattern and interaction of defects. In the dimensionless case, the equation contains only the parameter of structural scaling, i.e. the ratio of specific structural scales, including the size of defects and an average distance between the defects.The self-consistency equation yields three typical responds of the geomedium containing defects to the increasing external stress (Fig. 2). The responses are determined from values of the structural scaling parameter. The concept of non-equilibrium free energy for a medium containing defects, given similar to the Ginzburg-Landau decomposition, allowed to construct evolutionary equations for the introduced parameters of order (deformation due to defects, and the structural scaling parameter) and to explore their solutions (Fig. 3).It is shown that the first response corresponds to stable quasi-plastic deformation of the geomedium, which occurs in regularly located areas characterized by the absence of collective orientation effects. Reducing the structural scaling parameter leads to the second response characterized by the occurrence of an area of meta-stability in the behavior of the medium containing defects, when, at a certain critical stress, the orientation transition takes place in the ensemble of interacting defects, which is accompanied by an abrupt increase of deformation (Fig. 2). Under the given observation/averaging scale, this transition is manifested by localized cataclastic deformation (i.e. a set of weak earthquakes), which migrates in space at a velocity several orders of magnitude lower than the speed of sound, as a β€˜slow’ deformation wave (Fig. 3). Further reduction of the structural scaling parameter leads to degeneracy of the orientation meta-stability and formation of localized dissipative defect structures in the medium. Once the critical stress is reached, such structures develop in the blow-up regime, i.e. the mode of avalanche-unstable growth of defects in the localized area that is shrinking eventually. At the scale of observation, this process is manifested as brittle fracturing that causes formation of a deformation zone, which size is proportional to the scale of observation, and corresponds to occurrence of a strong earthquake.On the basis of the proposed model showing the behavior of the geomedium containing defects in the field of external stresses, it is possible to describe main ways of stress relaxation in the rock massives – brittle large-scale destruction and cataclastic deformation as consequences of the collective behavior of defects, which is determined by the structural scaling parameter.Results of this study may prove useful for estimation of critical stresses and assessment of the geomedium status in seismically active regions and be viewed as model representations of the physical hypothesis about the uniform nature of deveΒ­lopment of discontinuities/defects in a wide range of spatial scales

    Control Strategies of the Electrical Complex of High-Voltage Electricity Transmission Lines of the Direct Current

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    Π’ настоящСС врСмя спрос Π½Π° ΡΠ½Π΅Ρ€Π³ΠΈΡŽ растСт высокими Ρ‚Π΅ΠΌΠΏΠ°ΠΌΠΈ, ΠΈ Π²ΠΎΠ·Π½ΠΈΠΊΠ°ΡŽΡ‚ ΠΏΡ€ΠΎΠ±Π»Π΅ΠΌΡ‹, стоящиС ΠΏΠ΅Ρ€Π΅Π΄ ΠΈΠ½Ρ‚Π΅Π³Ρ€Π°Ρ†ΠΈΠ΅ΠΉ элСктричСской сСти, Π² ΠΏΠ΅Ρ€Π²ΡƒΡŽ ΠΎΡ‡Π΅Ρ€Π΅Π΄ΡŒ с ΠΏΠ΅Ρ€Π΅Π΄Π°Ρ‡Π΅ΠΉ энСргии Π½Π° большиС расстояния. Описанная Π²Ρ‹ΡˆΠ΅ ΠΏΡ€ΠΎΠ±Π»Π΅ΠΌΠ° ΠΌΠΎΠΆΠ΅Ρ‚ Π±Ρ‹Ρ‚ΡŒ Ρ€Π΅ΡˆΠ΅Π½Π° с использованиСм систСм ΠΏΠ΅Ρ€Π΅Π΄Π°Ρ‡ΠΈ HVDC. ΠžΡΠ½ΠΎΠ²Π½Ρ‹Π΅ прСимущСства этих систСм связаны с Π±ΠΎΠ»Π΅Π΅ Π½ΠΈΠ·ΠΊΠΈΠΌΠΈ потСрями ΠΏΡ€ΠΈ ΠΏΠ΅Ρ€Π΅Π΄Π°Ρ‡Π΅, Π° Ρ‚Π°ΠΊΠΆΠ΅ мСньшими Π·Π°Ρ‚Ρ€Π°Ρ‚Π°ΠΌΠΈ ΠΏΠΎ ΡΡ€Π°Π²Π½Π΅Π½ΠΈΡŽ с Ρ‚Ρ€Π°Π΄ΠΈΡ†ΠΈΠΎΠ½Π½Ρ‹ΠΌΠΈ систСмами ΠΏΠ΅Ρ€Π΅Π΄Π°Ρ‡ΠΈ HVAC. По ряду ΠΏΡ€ΠΈΡ‡ΠΈΠ½ тСхнология прСобразования напряТСния (ΠΏΡ€Π΅ΠΎΠ±Ρ€Π°Π·ΠΎΠ²Π°Ρ‚Π΅Π»ΡŒ источника напряТСния – VSC) с использованиСм ΡˆΠΈΡ€ΠΎΡ‚Π½ΠΎ-ΠΈΠΌΠΏΡƒΠ»ΡŒΡΠ½ΠΎΠΉ модуляции (ШИМ) систСмы ΠΏΠ΅Ρ€Π΅Π΄Π°Ρ‡ΠΈ постоянного Ρ‚ΠΎΠΊΠ° высокого напряТСния (VSC- HVDC) ΠΈΠΌΠ΅Π΅Ρ‚ ряд ΠΏΠΎΡ‚Π΅Π½Ρ†ΠΈΠ°Π»ΡŒΠ½Ρ‹Ρ… прСимущСств ΠΏΠΎ ΡΡ€Π°Π²Π½Π΅Π½ΠΈΡŽ с систСмой ΠΏΠ΅Ρ€Π΅Π΄Π°Ρ‡ΠΈ постоянного Ρ‚ΠΎΠΊΠ° с использованиСм ΠΏΡ€Π΅ΠΎΠ±Ρ€Π°Π·ΠΎΠ²Π°Ρ‚Π΅Π»Π΅ΠΉ с Π»ΠΈΠ½Π΅ΠΉΠ½ΠΎΠΉ ΠΊΠΎΠΌΠΌΡƒΡ‚Π°Ρ†ΠΈΠ΅ΠΉ (LCC-HVDC), Π² частности, упрощаСтся рСализация ΠΌΠ½ΠΎΠ³ΠΎΡ‚Π΅Ρ€ΠΌΠΈΠ½Π°Π»ΡŒΠ½Ρ‹Ρ… систСм ΠΏΠ΅Ρ€Π΅Π΄Π°Ρ‡ΠΈ постоянного Ρ‚ΠΎΠΊΠ° HVDC, появляСтся Π²ΠΎΠ·ΠΌΠΎΠΆΠ½ΠΎΡΡ‚ΡŒ Π±Ρ‹ΡΡ‚Ρ€ΠΎΠ΄Π΅ΠΉΡΡ‚Π²ΡƒΡŽΡ‰Π΅Π³ΠΎ ΠΈ нСзависимого рСгулирования Π°ΠΊΡ‚ΠΈΠ²Π½ΠΎΠΉ ΠΈ Ρ€Π΅Π°ΠΊΡ‚ΠΈΠ²Π½ΠΎΠΉ мощности, Π²ΠΎΠ·ΠΌΠΎΠΆΠ½ΠΎΡΡ‚ΡŒ Π΄Π²ΡƒΠ½Π°ΠΏΡ€Π°Π²Π»Π΅Π½Π½ΠΎΠΉ ΠΏΠ΅Ρ€Π΅Π΄Π°Ρ‡ΠΈ мощности ΠΏΡ€ΠΈ сохранСнии Π½Π΅ΠΈΠ·ΠΌΠ΅Π½Π½ΠΎΠΉ полярности напряТСния постоянного Ρ‚ΠΎΠΊΠ°. Благодаря высокой стСпСни управляСмости ΠΏΡ€Π΅ΠΎΠ±Ρ€Π°Π·ΠΎΠ²Π°Ρ‚Π΅Π»Π΅ΠΉ источника напряТСния (VSC) Π² основном рассматриваСтся Π² Π½Π΅Π΄Π°Π²Π½Π΅ΠΉ Π»ΠΈΡ‚Π΅Ρ€Π°Ρ‚ΡƒΡ€Π΅ Ρ€Π°Π±ΠΎΡ‚Π° HVDC. Π’ ΠΏΡ€ΠΎΡˆΠ»ΠΎΠΌ Π±Ρ‹Π»ΠΎ ΠΏΡ€ΠΎΠ²Π΅Π΄Π΅Π½ΠΎ ΠΌΠ½ΠΎΠ³ΠΎ исслСдований ΠΈ Ρ€Π°Π·Ρ€Π°Π±ΠΎΡ‚ΠΎΠΊ Π² области ΠΏΠ΅Ρ€Π΅Π΄Π°Ρ‡ΠΈ VSC-HVDC, особСнно Π² аспСктах Π΅Π΅ управлСния. Однако Π² Π±ΠΎΠ»ΡŒΡˆΠΈΠ½ΡΡ‚Π²Π΅ случаСв для описания ΠΎΠΏΠ΅Ρ€Π°Ρ†ΠΈΠΎΠ½Π½Ρ‹Ρ… характСристик Ρ€Π°Π·Π»ΠΈΡ‡Π½Ρ‹Ρ… ΠΏΡ€Π΅Π΄Π»Π°Π³Π°Π΅ΠΌΡ‹Ρ… стратСгий управлСния использовались Ρ‚ΠΎΠ»ΡŒΠΊΠΎ качСствСнныС ΠΌΠ΅Ρ‚ΠΎΠ΄Ρ‹. ΠŸΠΎΡΡ‚ΠΎΠΌΡƒ Ρ†Π΅Π»ΡŒ ΠΈΡΡΠ»Π΅Π΄ΠΎΠ²Π°Ρ‚Π΅Π»ΡŒΡΠΊΠΎΠΉ Ρ€Π°Π±ΠΎΡ‚Ρ‹ Π² этой ΡΡ‚Π°Ρ‚ΡŒΠ΅ – Π·Π°ΠΏΠΎΠ»Π½Π΅Π½ΠΈΠ΅ Π½Π΅ΠΊΠΎΡ‚ΠΎΡ€Ρ‹Ρ… ΠΏΡ€ΠΎΠ±Π΅Π»ΠΎΠ², Ρ‚Π°ΠΊΠΈΡ… ΠΊΠ°ΠΊ исслСдованиС Ρ€Π°Π·Π»ΠΈΡ‡Π½Ρ‹Ρ… стратСгий управлСния Ρ‚Π΅Ρ€ΠΌΠΈΠ½Π°Π»Π°ΠΌΠΈ VSC-HVDC для использования Π² сСтях постоянного Ρ‚ΠΎΠΊΠ°Currently, the demand for energy is growing at a high rate, and there are problems facing the integration of the electrical network, primarily with the transmission of energy over long distances. The problem described above can be solved using HVDC transmission systems. The main advantages of these transmission systems are associated with lower transmission losses as well as lower costs compared to traditional HVAC transmission systems. For a number of reasons, voltage conversion technology (Voltage Source Converter – VSC) using Pulse Width Modulation (PWM) high voltage direct current (VSC-HVDC) transmission system has a number of potential advantages over a DC transmission system using line commutated converters. (LCC-HVDC), in particular, the implementation of multi-terminal HVDC DC transmission systems is simplified, it becomes possible to quickly and independently control active and reactive power, the possibility of bidirectional power transmission while maintaining the same DC voltage polarity. Due to the high degree of controllability of voltage source converters (VSC), it is mainly dealt with in the recent literature on HVDC operation. Much research and development has been done in the past in the field of VSC-HVDC transmission, especially in its control aspects. However, in most cases, only qualitative methods have been used to describe the operational characteristics of the various proposed management strategies. Therefore, the purpose of the research work in this article is to fill in some of the gaps, such as investigating different control strategies for VSC-HVDC terminals for use in DC network

    Effective Targeted Chemoprophylaxis of Recurrent Liver Echinococcosis with Haplotype CYP1A2F1*A/A: a Clinical Case

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    Background. One of the main longΒ­term quality criteria for treatment and prevention of echinococcosis is postoperativeΒ relapse, which rate varies widely within 3–54% between medical facilities. The genetic traits of recurrent liver echinococcosis comprise an important subject of research into its etiopathogenetic factors forΒ  an effective prognosis of cyst relapseΒ and treatment personalisation.Materials and methods. Bashkir State Medical University (Ufa, Russia) provided facilities to study targetedΒ  chemoprophylaxis efficacy in a case of relapsed liver echinococcosis with haplotype CYP1A2F1*A/A (AA) and theΒ  UM phenotype ofΒ ultrarapid albendazole sulfoxideΒ­toΒ­albendazole sulfone metaboliser.Results and discussion. The clinical case presented illustrates the rationale behind personalisedΒ  chemoprevention of recurrent echinococcosis with albendazole based on genotyping data. Genotyping allowsΒ  detection of an ultrafast metaboliserΒ haplotype in blood implicating a rapid degradation of administered albendazole, reduced antiparasitic impact of drugΒ therapy and more feasible relapse, in contrast with a normal metaboliser phenotype.Conclusion. A successful secondary prevention of relapsed echinococcosis suggests the efficacy of personalisingΒ  albendazoleΒ­based chemoprophylaxis of recurrent echinococcosis with genotyping data

    Power Flow Control in Multi-Terminal Electrical Complexes, Taking Into Account the Effect of Dc Line Resistance

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    ΠŸΠΎΡ‚Π΅Ρ€ΠΈ ΠΈΠ·-Π·Π° сниТСния напряТСния Π² Π»ΠΈΠ½ΠΈΠΈ постоянного Ρ‚ΠΎΠΊΠ° ΠΎΠΊΠ°Π·Ρ‹Π²Π°ΡŽΡ‚ Π·Π½Π°Ρ‡ΠΈΡ‚Π΅Π»ΡŒΠ½ΠΎΠ΅ влияниС Π½Π° Ρ‚ΠΎΡ‡Π½ΠΎΠ΅ ΡƒΠΏΡ€Π°Π²Π»Π΅Π½ΠΈΠ΅ ΠΏΠΎΡ‚ΠΎΠΊΠΎΠΌ мощности Π² ΠΌΠ½ΠΎΠ³ΠΎΡ‚Π΅Ρ€ΠΌΠΈΠ½Π°Π»ΡŒΠ½Ρ‹Ρ… систСмах ПИН-Π’ΠŸΠŸΠ’ с использованиСм управлСния напряТСниСм Π½Π° ΡˆΠΈΠ½Π°Ρ… постоянного Ρ‚ΠΎΠΊΠ°. Когда ΡƒΠΏΡ€Π°Π²Π»Π΅Π½ΠΈΠ΅ напряТСниСм Π½Π° ΡˆΠΈΠ½Π°Ρ… постоянного Ρ‚ΠΎΠΊΠ° ΠΈΡΠΏΠΎΠ»ΡŒΠ·ΡƒΠ΅Ρ‚ΡΡ Π² ΠΌΠ½ΠΎΠ³ΠΎΡ‚Π΅Ρ€ΠΌΠΈΠ½Π°Π»ΡŒΠ½Ρ‹Ρ… систСмах ПИН- Π’ΠŸΠŸΠ’, ΠΈΠ·-Π·Π° Π½Π΅Ρ€Π°Π²Π½Ρ‹Ρ… напряТСний Π½Π° ΡˆΠΈΠ½Π°Ρ… постоянного Ρ‚ΠΎΠΊΠ° сниТСния напряТСния Π² Π»ΠΈΠ½ΠΈΠΈ постоянного Ρ‚ΠΎΠΊΠ° Π²ΠΎΠ·Π½ΠΈΠΊΠ°ΡŽΡ‚ большиС отклонСния ΠΏΠΎΡ‚ΠΎΠΊΠ° мощности. ΠŸΠΎΡ‚Π΅Ρ€ΠΈ мощности Π² Π»ΠΈΠ½ΠΈΠΈ постоянного Ρ‚ΠΎΠΊΠ° ΠΈ Π² прСобразоватСлях Ρ‚Π°ΠΊΠΆΠ΅ Π²Ρ‹Π·Ρ‹Π²Π°ΡŽΡ‚ отклонСния ΠΏΠΎΡ‚ΠΎΠΊΠ° мощности Π² сСти постоянного Ρ‚ΠΎΠΊΠ° ΠΎΡ‚ ΠΆΠ΅Π»Π°Π΅ΠΌΠΎΠ³ΠΎ значСния. Для Ρ‚ΠΎΡ‡Π½ΠΎΠ³ΠΎ управлСния ΠΏΠΎΡ‚ΠΎΠΊΠΎΠΌ мощности Π² сСти постоянного Ρ‚ΠΎΠΊΠ° Π½Π΅ΠΎΠ±Ρ…ΠΎΠ΄ΠΈΠΌΠΎ ΡƒΡΡ‚Ρ€Π°Π½ΠΈΡ‚ΡŒ отклонСния мощности, Π²ΠΎΠ·Π½ΠΈΠΊΠ°ΡŽΡ‰ΠΈΠ΅ ΠΈΠ·-Π·Π° ΠΊΠ°ΠΆΠ΄ΠΎΠ³ΠΎ ΠΈΠ· этих Ρ„Π°ΠΊΡ‚ΠΎΡ€ΠΎΠ². ΠŸΡ€ΠΈ ΠΌΠΎΠ΄Π΅Π»ΠΈΡ€ΠΎΠ²Π°Π½ΠΈΠΈ ΠΏΡΡ‚ΠΈΡ‚Π΅Ρ€ΠΌΠΈΠ½Π°Π»ΡŒΠ½ΠΎΠΉ систСмы ПИН-Π’ΠŸΠŸΠ’ Π² Matlab/ Simulink ΠΏΠΎΠΊΠ°Π·Π°Π½ΠΎ, ΠΊΠ°ΠΊ Π΄ΠΎΠ±ΠΈΡ‚ΡŒΡΡ Ρ‚ΠΎΡ‡Π½ΠΎΠ³ΠΎ управлСния ΠΏΠΎΡ‚ΠΎΠΊΠΎΠΌ мощности Π² систСмС с ΡƒΡ‡Π΅Ρ‚ΠΎΠΌ сниТСния напряТСния постоянного Ρ‚ΠΎΠΊΠ° ΠΈ ΠΏΠΎΡ‚Π΅Ρ€ΡŒ мощности Π² Π»ΠΈΠ½ΠΈΠΈ постоянного Ρ‚ΠΎΠΊΠ° (ΡƒΡ‡Π΅Ρ‚ ΠΏΠΎΡ‚Π΅Ρ€ΡŒ мощности прСобразоватСля Π²Ρ‹Ρ…ΠΎΠ΄ΠΈΡ‚ Π·Π° Ρ€Π°ΠΌΠΊΠΈ Π΄Π°Π½Π½ΠΎΠΉ ΡΡ‚Π°Ρ‚ΡŒΠΈ)Losses due to voltage drop in the DC line have a significant impact on the accurate control of power flow in multi-terminal VSC-HVDCs using DC voltage droop control. When DC voltage droop controls are used in multi-terminal VSC-HVDC, due to unequal DC bus voltages, voltage drops in the DC link cause large power flow variations in the DC grid. Power losses in the DC link and converter power losses also cause deviations in the power flow in the DC network. To accurately control the power flow in a DC network, it is necessary to eliminate the power deviations that occur due to each of these factors. Modeling a five-terminal VSC-HVDC system in Matlab/Simulink shows how to achieve precise power flow control in a multi-terminal VSC-HVDC, taking into account the reduction of DC voltage and power losses in the DC line (accounting for converter power losses is beyond the scope of this article

    Influence of DC Line Resistance on Power Balance Distribution in Multi-Terminal Electrical Complexes

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    Π’ этой ΡΡ‚Π°Ρ‚ΡŒΠ΅ обсуТдаСтся влияниС сопротивлСния Π»ΠΈΠ½ΠΈΠΈ постоянного Ρ‚ΠΎΠΊΠ° Π½Π° распрСдСлСниС баланса мощности систСмы постоянного Ρ‚ΠΎΠΊΠ° МППВ ΠΏΡ€ΠΈ стабилизации напряТСния постоянного Ρ‚ΠΎΠΊΠ°. Π‘ΠΎΠΏΡ€ΠΎΡ‚ΠΈΠ²Π»Π΅Π½ΠΈΠ΅ Π»ΠΈΠ½ΠΈΠΈ постоянного Ρ‚ΠΎΠΊΠ° Π² ΠΌΠ½ΠΎΠ³ΠΎΡ‚Π΅Ρ€ΠΌΠΈΠ½Π°Π»ΡŒΠ½ΠΎΠΉ систСмС MППВ ΠΏΡ€ΠΈΠ²ΠΎΠ΄ΠΈΡ‚ ΠΊ измСнСниям напряТСния Π½Π° шинС постоянного Ρ‚ΠΎΠΊΠ° ΠΏΡ€ΠΈ ΠΈΠ·ΠΌΠ΅Π½Π΅Π½ΠΈΠΈ ΠΏΠΎΡ‚ΠΎΠΊΠ° мощности Π² систСмС. Π­Ρ‚ΠΎ, Π² свою ΠΎΡ‡Π΅Ρ€Π΅Π΄ΡŒ, влияСт Π½Π° распрСдСлСниС ΠΌΠ³Π½ΠΎΠ²Π΅Π½Π½ΠΎΠ³ΠΎ баланса мощности Π² систСмС МППВ ΠΏΡ€ΠΈ ΡƒΠΏΡ€Π°Π²Π»Π΅Π½ΠΈΠΈ с Ρ†Π΅Π»ΡŒΡŽ стабилизации напряТСния постоянного Ρ‚ΠΎΠΊΠ°. ЗначСния коэффициСнта усилСния напряТСния постоянного Ρ‚ΠΎΠΊΠ° ΠΎΠΏΡ€Π΅Π΄Π΅Π»ΡΡŽΡ‚ ΡΡ‚Π΅ΠΏΠ΅Π½ΡŒ влияния сниТСния напряТСния постоянного Ρ‚ΠΎΠΊΠ° Π½Π° распрСдСлСниС баланса мощности Π² систСмС постоянного Ρ‚ΠΎΠΊΠ°. Π’ Π΄Π°Π½Π½ΠΎΠΉ ΡΡ‚Π°Ρ‚ΡŒΠ΅ ΠΏΠΎΠ»ΡƒΡ‡Π΅Π½Π° матСматичСская модСль для ΠΎΡ†Π΅Π½ΠΊΠΈ распрСдСлСния баланса мощности с ΡƒΡ‡Π΅Ρ‚ΠΎΠΌ влияния сопротивлСния постоянного Ρ‚ΠΎΠΊΠ°. БистСма МППВ с ΠΏΡΡ‚ΡŒΡŽ Ρ‚Π΅Ρ€ΠΌΠΈΠ½Π°Π»Π°ΠΌΠΈ ПИН-Π’ΠŸΠŸΠ’ Π±Ρ‹Π»Π° смодСлирована Π² ΠΏΡ€ΠΎΠ³Ρ€Π°ΠΌΠΌΠ½ΠΎΠΌ ΠΏΠ°ΠΊΠ΅Ρ‚Π΅ Matlab/Simulink для дСмонстрации влияния сопротивлСния Π»ΠΈΠ½ΠΈΠΈ постоянного Ρ‚ΠΎΠΊΠ° Π½Π° распрСдСлСниС баланса мощности, Π° Ρ‚Π°ΠΊΠΆΠ΅ для ΠΏΡ€ΠΎΠ²Π΅Ρ€ΠΊΠΈ ΠΏΡ€Π΅Π΄Π»ΠΎΠΆΠ΅Π½Π½ΠΎΠΉ матСматичСской ΠΌΠΎΠ΄Π΅Π»ΠΈ, которая ΠΎΡ†Π΅Π½ΠΈΠ²Π°Π΅Ρ‚ распрСдСлСниС баланса мощностиThis article discusses the impact of direct current resistance on the distribution of the power of the DC power system of the MPPT when stabilizing direct current voltage. The resistance of the DC line in the multi-terminal MTDC system leads to changes in the voltage on the direct current with a change in power flow in the system. This, in turn, affects the distribution of instant power balance in the MTDC system during control in order to stabilize direct current voltage. The values of the direct current voltage reinforcement values determine the degree of influence of a reduction in direct current on the distribution of power balance in the DC system. In this article, a mathematical model was obtained to assess the distribution of power balance, taking into account the effect of direct current resistance. The MTDC system with five VSC-HVDC terminals was modeled in the Matlab/Simulink software package to demonstrate the impact of direct current resistance on the distribution of power balance, as well as to check the proposed mathematical model, which evaluates the distribution of power balanc
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