Wyniki wyszukiwania - BazTech

1

High availability model of a web service from a system administrator’s perspective

Wirski Robert Tomasz

Zeszyty Naukowe Politechniki Morskiej w Szczecinie

|

2024

|

nr 77 (149)

99--106

EN

Based on cloud providers’ reports on service outages, it has become clear that how a web service is deployed is of great importance. Clearly, using one service supplier is insufficient because it introduces single points of failure. In this paper, a novel high-availability multi-cloud model intended for a web service is proposed, which is free from such shortcomings yet preserves convenient assets of computing clouds. The methodology used to improve web service availability should involve several cloud suppliers and devise management techniques that control access to them. This is achieved by means of the server availability tracking algorithm, which controls client apps’ access to the service. Moreover, typical benefits and problems involved in choosing IT infrastructure for a web service are elaborated. State-of-the-art cloud computing models, such as IaaS, PaaS, SaaS, BPaaS, and INaaS, are outlined. Operating systems statistics used for web services are included. Open-source monitoring software solutions are gathered, which help administrators to monitor and govern web servers.

2

Availability analysis of vertical milling centre using Markov approach and Monte Carlo simulations

Kumar Girish, Mishra Ravi, Khan Tayyab

Safety and Reliability of Systems and Processes

|

2023

|

Summer Safety and Reliability Seminar 2023

117--130

EN

The purpose of this article is to investigate the availability of vertical machining centre using a Markovian technique and Monte Carlo simulation (MSC). Availability is a critical performance metric for industrial systems. Conventional methodologies focus for steady-state availability evaluation of mechanical systems. The research analyses transient availability assessment for four different system configurations. Monte Carlo simulation modelling is used to compare the results and future scope is suggested to use the developed MCS based algorithms/codes for non-exponential (time dependant) failure and repair time distributions. The research also investigates the influence of active and passive redundancy on availability, indicating that for the vertical machining centre, parallel architecture with standby redundancy outperforms active load sharing. The chapter includes a sensitivity study that modifies the repair rates of the ball screw and sub-assembly to make the component selection process easier for engineers. The authors believe that this chapter will be useful to maintenance and practising engineers because it will assist them in making informed decisions about system availability, developing maintenance/replacement policies, and determining the repair level required to achieve the desired system availability.

3

Electrical power and energy balance in the local electrical system by using reconciliation of the generation and consumption schedules

Lezhniuk Petro, Kozachuk Oleh, Komenda Natalia, Malogulko Juliya

Przegląd Elektrotechniczny

|

2023

|

R. 99, nr 9

57--63

EN

The paper considers the problem of balancing power and electricity in a local electric power system (LES), in which electricity consumption and its generation by renewable energy sources (RES) are proportional to each other. In the LES, the principle is implemented - what is generated is consumed by its own consumers. The LES is considered as part of an electric power system (EPS) with large power plants, but which can operate in an autonomous mode. The sources of electricity in the LES are small hydroelectric power plants (SHPP), photovoltaic and wind power plants (PV, WPP), the production of which is unstable due to dependence on natural conditions. That is why the LES provides for reserve existing maneuvering capacity, electrochemical storage, hydrogen technologies and biogas plants in the UES. To assess the possibility and effectiveness of methods and means of reserving the instability of RES electricity production, the criterion method of the similarity theory was used. From the analysis of the proportionality and sensitivity of the relative costs of RES reserve capabilities and means, it is shown that the best are hydrogen technologies and the coordination of electricity generation and consumption schedules in the RES. First of all, we recommend to use the possibility of using electricity generation and consumption schedules in the LES. For the amount of electricity that remained unbalanced after such reconciliation, it is advisable to use the hydrogen produced in the LES for full balancing. Coordination of generation and consumption schedules in the LES for balancing electricity in it is carried out using a morphometric apparatus, which is based on the transition from the Cartesian to the polar coordinate system. It is shown that the use of a morphometric apparatus for analyzing the unevenness of graphs has a number of advantages and allows for a comprehensive and detailed assessment of the graphs shape. Conditions are created for monitoring the dynamics of changes in consumption and generation schedules in the LES and assessing the impact on the technological processes of electricity consumers.

PL

W artykule rozpatruje się problem balansowania mocy i energii elektrycznej w lokalnym systemie elektroenergetycznym (LSE), w którym zużycie energii elektrycznej i jej generowanie przez odnawiane źródła energii (OZE) są dostosowane do siebie. W LSE realizuje się zasadę: to, co zostało wyprodukowane, jest spożywane przez jej własnych użytkowników. LSE jest rozpatrywana jako część składowa systemu elektroenergetycznego (SEE) z dużymi elektrowniami, ale posiadająca możliwość pracy autonomicznej. Żródłami energii elektrycznej w LSE są małe hydroeletrownie (MHE), fotoelektrownie I elektownie wiatrowe (FE, EW), produkowanie energii elektrycznej przez które nie jest stabilne ze względu na zależność od warunków pogodowych. Przeto w LSE są przewidziane rezerwowe moce manewrowe, zbiorniki elektrochemiczne, technologie wodorowe i urządzenia biogazowe. Dla oceny możliwości i skuteczności sposobów i metod rezerwowania niestabilności generowania energii elektrycznej OZE wykorzystano metodę kryterialną teorii podobieństwa. Analiza proporcjonalności i wrażliwości kosztów względnych do ewentualnych sposobów i srodków rezerwowania OZE pokazała, że najlepsze są technologie wodorowe i uzgodnienie wykresów generowania i zużycia energii elektrycznej w LSE. W pierwszej kolejności zaleca się wykorzystanie możliwości uzgadniania w LSE wykresów generowania I zużycia energii elektrycznej. Do ilości energii elektrycznej, która nie jest balansowanie po takim uzgodnieniu, dla pełnego wyrównania zalecane jest wykorzystanie wyprodukowanego w LSE wodoru. Uzgodnienie wykresów generowania i zużycia w LSE w celu wyrównania w nim energii elektrycznej jest realizowane przy użyciu aparatu morfometrycznego, zasadą którego jest przejście od kartezjańskiego do biegunowego układu współrzędnych. Zademonstrowano, że wykorzystanie aparatu morfometrycznego w celu analizy nierównomierności wykresów ma szereg przewag i pozwala na przeprowadzenie wszechstronnego i szczegółowego oceniania formy wykresów. Stwarza się warunki dla śledzenia dynamiki zmian wykresów zużycia i generowania w LSE i oceniania wpływu na procesy technologiczne konsumentów energii elektrycznej.

4

Hydrogen technologies as a method of compensation for inequality of power generation by renewable energy sources

Kudria Stepan, Lezhniuk Petr, Riepkin Oleksandr, Rubanenko Olena

Przegląd Elektrotechniczny

|

2022

|

R. 98, nr 10

1--6

EN

The method and methods of reserving the instability of the generation of renewable energy sources (RES) in electric power systems (EPS) caused by weather conditions are analyzed. It is shown that these can be shunting power plants and various types of energy storage. Existing maneuvering capacities and hydrogen technologies with biogas plants are considered as a reserve for the development and increase of RES capacity in power systems. Attention is mainly paid to the problem of participation of photovoltaic power plants (PV plant) in balancing power and electricity in the power system. An algorithm for using hydrogen as an energy source to reduce the error between the actual and projected hourly schedules of PV plant generation in the balancing group is considered. Mathematical models are developed on the basis of similarity theory and criterion method. This approach, with the least available source information, provides an opportunity to compare different methods of redundancy of non-uniformity of PV plant generation, assess their proportionality, as well as determine the sensitivity of costs to the power of redundancy methods. Criteria models have been formed, which allow to build the dependences of the costs for redundancy of non-uniformity of power generation on the capacity of hydrogen-type storage devices and on the capacity of the system reserve together with the capacity of power transmission lines. It is shown that such dependencies make it possible to more reasonably choose certain methods of reservation in accordance with the characteristics and requirements of the EPS.

PL

Przeanalizowano sposób i metody rezerwowania niestabilności wytwarzania odnawialnych źródeł energii (OZE) w systemach elektroenergetycznych (SEE) wywołanych warunkami atmosferycznymi. Wykazano, że mogą to być elektrownie manewrowe i różnego rodzaju magazyny energii. Istniejące zdolności manewrowe i technologie wodorowe wraz z biogazowniami traktowane są jako rezerwa dla rozwoju i zwiększenia mocy OZE w systemach elektroenergetycznych. Zwrócono uwagę przede wszystkim na problem udziału elektrowni fotowoltaicznych (elektrowni fotowoltaicznych) w bilansowaniu mocy i energii elektrycznej w systemie elektroenergetycznym. Rozważany jest algorytm wykorzystania wodoru jako źródła energii w celu zmniejszenia błędu pomiędzy rzeczywistymi i przewidywanymi harmonogramami godzinowymi wytwarzania elektrowni fotowoltaicznych w grupie bilansowej. Modele matematyczne tworzone są w oparciu o teorię podobieństwa i metodę kryteriów. Takie podejście, przy najmniej dostępnych informacjach źródłowych, daje możliwość porównania różnych metod redundancji niejednorodności generacji fotowoltaicznej, oceny ich proporcjonalności, a także określenia wrażliwości kosztów na moc metod redundancyjnych. Powstały modele kryterialne, które pozwalają na zbudowanie zależności kosztów redundancji niejednorodności wytwarzania energii od pojemności zasobników typu wodorowego oraz od pojemności rezerwy systemu wraz z przepustowością linii elektroenergetycznych. Wykazano, że takie zależności pozwalają na bardziej rozsądny dobór pewnych sposobów rezerwacji zgodnie z charakterystyką i wymaganiami systemów elektroenergetycznych.

5

Reliability of Communication Systems Used in Offshore Wind Farms

Uhl Tadeusz

Journal of Telecommunications and Information Technology

|

2022

|

nr 4

61--66

EN

In the era of renewable energy, offshore wind farms play a very important role. The number of such installations in Europe is increasing rapidly. With the growing capacity of wind turbines installed in these farms (3, 5, 10 MW), the profitability of this type of energy systems plays an increasing role. The number of wind energy turbines installed at offshore wind farms is growing constantly as well. Once installed, the power plants must be under constant technical supervision, with reliability of electronic communication systems being a particularly important aspect in the operation of offshore wind farms. Considerations focusing on this subject form the very core of this paper. After an introduction to offshore wind farms, the following aspects will be discussed: redundant topologies, e.g. multiple HiPERRings, redundant switches and routers within the backbone networks, redundancy of the transmission media used, alternative transmission technologies, e.g. WLANs (IEEE 802.11h, IEEE 802.11g). Finally, requirements applicable to reliable electronic communication systems used in offshore wind farms will be formulated.

6

Markov reliability models of series systems with redundancy and repair facilities

Zhernovyi Yuriy, Kopytko Bohdan

Journal of Applied Mathematics and Computational Mechanics

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2021

|

Vol. 20, nr 3

89--96

EN

In this paper, we use Markov models for studying the reliability of series systems with redundancy and repair facilities. We suppose that the units’ time to failure and recovery times are exponentially distributed. We consider the cases when 1≤ c ≤ m and m + 1 ≤ c ≤ m + n, for the system of n operating units, m unloaded redundant units and c repair facilities. Using the exponential distributions properties, we obtain stationary reliability indices of the series systems: steady-state probabilities, a stationary availability coefficient, mean time to failure, mean time between failures and mean downtime.

7

A method for evaluating and upgrading systems with parallel structures with forced redundancy

Michlowicz Edward, Wojciechowski Jerzy

Eksploatacja i Niezawodność

|

2021

|

Vol. 23, no. 4

770--776

EN

The objects of the study are parallel-structure machine systems with redundancy associated with safety assurance of continuous material flow. The problem concerns systems in which the supply of materials takes place continuously (24 hours a day), and the system of operated machines must ensure the receipt and movement of the material at a strictly defined time and in the desired quantity. It is a system where the presence of a failure poses a threat to human life and environmental degradation. This paper presents a method for system condition assessment and upgrading for maintaining proper operation under conditions of continuous operation. A database of information about the current parameters of the system components (measurements, monitoring) is necessary for condition assessment. The method also uses lean techniques (including TPM). System evaluation and selection criteria for a suitable structure in terms of further operation were proposed. Exemplification was performed for an underground mine drainage system. As a part of the identification, selected parameters of the system components were measured, and their characteristics (motors, pumps, pipelines) were developed. The results of the analysis and the values of the adopted criteria were compared to the indicators for new pump sets. A two-option system upgrade was proposed, in addition to machine operating schedules, maintenance periods, and overhaul cycles.

8

Optimal allocation of the electrical structure design using the bats approach

Chaker Abdelkader, Benaissa Abdelkader, Zablah Abdelkader, Belfedhal Alaa Eddine

Przegląd Elektrotechniczny

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2020

|

R. 96, nr 6

98--102

EN

In this paper we describe and use a meta-heuristic optimization method is the algorithm of bats to be able to solve the problem of optimizing redundancy. This problem is known because we will strive to reduce the investment cost of the serial-parallel power system configuration through the algorithm, not to mention to maximize reliability and this is one of the constraints. Redundant components are included to achieve the desired level of availability, and service continuity. The maintainability of the system is based on a multi-state availability function. The elements of the power system are characterized by their performance, reliability, and availability and cost. These elements are chosen from a list of products available on the market. The meta-heuristic proposed seeks the best solution for a better configuration for our structure, which composes the system to be able to minimize the cost with the desired maximum reliability. To estimate the availability of the serial-parallel power system, a fast method based on the universal moment generation (UMGF) function is suggested. The algorithm approach of bats is used as an optimization technique. One gives an example of a power supply system for present simulation

PL

Opisano I zastosowano meta heurystyczną metodę optymalizacji problemu redundancji. Optymalizacja ma na celu redukcję kosztów szeregowo-równoległego systemu dystrybucyjnego. Elementy systemu były opisywane przez ich właściwości, niezawodność i dostępność.

9

Reliability assessment of a series system with redundancy and repair facilities

Zhernovyi Yuriy, Kopytko Bohdan

Journal of Applied Mathematics and Computational Mechanics

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2020

|

Vol. 19, nr 3

123--131

EN

In this paper, we propose a method for studying the reliability of series systems with redundancy and repair facilities. We consider arbitrary distributions of the units’ time to failure and exponentially distributed recovery times. The approach based on the use of fictitious phases and hyperexponential approximations of arbitrary distributions by the method of moments. We consider cases of fictitious hyperexponential distributions with paradoxical and complex parameters. We define conditions for the variation coefficients of the gamma distributions and Weibull distributions, for which the best and same accuracy of calculating the steady-state probabilities is achieved in comparison with the results of simulation modeling.

10

Elements of the statistical system for vibration tests of machine

Żółtowski Bogdan

Vibrations in Physical Systems

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2019

|

Vol. 30, nr 2

art. no. 2019209

EN

Presented considerations of this work includes selected issues in the area of statistical procedures use in vibration measures study and modal analysis methods to assess the machines state. The indicated statistical procedures are particularly important in vibration and modal research, where the multidimensionality of diagnostic signals requires a wide application of various statistical procedures at the stage of processing and decision-making. This paper presents the MATLAB program for determination of the Symptoms matrix, software tools for reading and exporting files to the unv format, the OPTIMUM computer algorithm, the Singular Values Decomposition (SVD) computer algorithm and the state matrix analysis program using the MAC theory.

11

Safety of complex aircraft ergatic systems

Pila Jan, Kozuba Jarosław

Transport Problems

|

2019

|

T. 14, z. 2

101--110

EN

In this paper, aircraft safety of complex critical systems in terms of the automation and safety has been investigated. We think, due to the automation, the role of operators has shifted from active control to passive monitoring. Performing this last task even might be more difficult because of the monotony and needs of realization of the active control in emergency situation. The management of complex ergatic systems is relevant at the present stage of the development of science and technology. It is a particular concern to evaluate the activity of an operator as the element of the ergatic system. New technologies presented by automation should complement and not displace human functions in aircraft control. The paper focuses on new technologies applied in aircraft systems to ensure higher safety and system reliability. The main problem of aircraft safety is addressed to aircraft critical systems as helicopter transmission system monitoring, aircraft system integration, and system redundancy. The research is based on experimental methods and case studies. The subject of the research is to evaluate the importance of complex ergatical systems, e.g., interaction between the subject and the object in its operational process. As the example of helicopter main gearbox diagnostics, as an object of complex engineering system, is stated hypothesis that there is possibility to determine changes in the characteristics of critical flight parameters and to determine the current level of flight hazard. The work is based on experimental and measurementbased testing, systematic and scientific procedure of data collection, analysis and interpretation. The practical implication can be utilized for safety benefits, risk mitigation and avoidance.

12

Strategie tolerowania błędów w czasie pracy systemu informatycznego

Jóźwiak I., Legut J.

Zeszyty Naukowe. Organizacja i Zarządzanie / Politechnika Śląska

|

2018

|

z. 130

285--292

PL

W artykule przedstawiono metody detekcji błędów w czasie pracy systemu informatycznego. Wskazano, że techniki unikania błędów powinny być wspomagane przez narzędzia sprzętowe i programowe. W pracy zaproponowano strategię tolerowania błędów w czasie pracy systemu informatycznego. Opisano w jaki sposób identyfikuje się obszary problemowe oraz jak na ich podstawie określić można cele związane z ograniczeniem występowania błędów.

EN

This article presents methods of detecting errors in computer science systems during their work. It shows, that techniques of avoiding errors should be supported by program tools and processing equipment. Article offers : strategy of tolerating errors in computer science systems, describes how to find problematic areas and suggest how to define targets, that could eliminate appearing errors.

13

Redundancy as a way increasing reliability of ship power plants

Tarelko W.

New Trends in Production Engineering

|

2018

|

Vol. 1, Iss. 1

515--522

EN

One of key ways of assuring a high level of reliability of a ship power plant is to design redundancy of its structural elements, for example redundancy of prime drivers, drivelines etc. This paper deals with issues related to the redundancy as a way increasing dependability of the ship power and propulsion systems. Especially, fundamental characteristics of dependability, major design strategies influencing the reliability, and types of redundancies related to ship power and propulsion systems are presented.

14

Capabilities of local and remote monitoring and control of equipment used in marine ship industry

Albrecht A., Muc A.

New Trends in Production Engineering

|

2018

|

Vol. 1, Iss. 1

135--141

EN

This article presents two aspects regarding marine equipment control and monitoring. The first one is the issue of remote and local control in the maritime and land industry. The second is the economical and efficient use of redundant devices. This article describes the structure of remote control implemented on vessels. Paper presents an idea of control that combines remote and local control to provide optimal use of redundant devices with simultaneous increase of system reliability. The whole concept is shown on the built physical model with the control and operator panels. The control was implemented using freely programmable controller and HMI panel.

15

Selection measure of energy propagation in vibration diagnostic and modal analysis methods

Żółtowski B., Żółtowski M.

Diagnostyka

|

2018

|

Vol. 19, No. 4

19--26

EN

Presented considerations of this work includes selected issues in the area of statistical procedures use in vibration measures study and modal analysis methods to assess the building structures and machines state. The indicated statistical procedures are particularly important in vibration and modal research, where the multidimensionality of diagnostic signals requires a wide application of various statistical procedures at the stage of processing and decision-making. This paper presents the MATLAB program for determination of the Symptoms matrix, software tools for reading and exporting files in the .unv format, the OPTIMUM computer algorithm, the Singular Values Decomposition (SVD) computer algorithm and the state matrix analysis program using the MAC theory.

PL

Przedstawione rozważania tej pracy obejmują wybrane zagadnienia z obszaru wykorzystania procedur statystycznych w badaniu miar drganiowych oraz metod analizy modalnej do oceny stanu zużycia konstrukcji budowlanych i maszyn. Wskazane procedury statystyczne są szczególnie istotne w badaniach drganiowych i modalnych, gdzie wielowymiarowość sygnałów diagnostycznych wymaga szerokiego stosowania różnych procedur statystycznych na etapie przetwarzania oraz podejmowania decyzji. W tej pracy przedstawiono program MATLAB do wyznaczania macierzy Symptomów, narzędzia programowe do odczytu i eksportu plików w formacie .unv, algorytm komputerowy OPTIMUM, algorytmu komputerowej analizy rozkładu (SVD) i programu do analizy macierzy stanu z wykorzystaniem teorii MAC.

16

Wybrane strategie sterowania redundantnymi urządzeniami okrętowymi

Albrecht A., Muc A., Szeleziński A.

Zeszyty Naukowe Akademii Morskiej w Gdyni

|

2017

|

nr 100

9--19

PL

Artykuł przedstawia wybrane strategie sterowania urządzeniami redundantnymi zawarte w jednym programie, dzięki czemu istnieje możliwość zmiany trybu pracy w zależności od sytuacji i zapotrzebowania. Sterowanie zrealizowano z wykorzystaniem sterownika programowalnego PLC oraz panelu operatorskiego HMI. Celem pracy było przedstawienie kilku uzupełniających się rozwiązań, do efektywnego i optymalnego wykorzystania urządzeń okrętowych.

EN

This paper presents selected control strategies of redundant devices implicted in one program so that there is a possibility to change the operating mode depending on situation. The problem was evolved on pumps example becaue of their often use both in marine, and shore environment. Simulation model was based on two parallel pumps working in one system. First and second control mode assumes one of the pump working as ‘Master’ and second as ‘Stand-by’. It gives freedom in selection which pump is ‘Master’ and opportunity to change the choice. Third mode comprehends rotating work of two pumps depending on medium pressure value in the system. The control was implemented by using Programmable Logic Controller (PLC) and Human Machine Interface (HMI). Described strategies were checked and simulated in a few different configurations. The aim was to present several complementary solutions to achieve efficient and optimum use of the devices.

17

Zastosowanie redundancji w siłowniach okrętowych statków oceanotechnicznych

Tarełko W.

Przegląd Mechaniczny

|

2017

|

nr 12

34--40

PL

Systemy wytwarzania energii i napędu statków oceanotechnicznych muszą mieć bardzo wysoki poziom niezawodności. Utrata zdolności do wykonywania funkcji przez ich elementy strukturalne z reguły powoduje bardzo wysokie straty ekonomiczne. Straty te mogą być zwiększone przez niemożność wykorzystania tzw. okna pogodowego, skutkującego odłożeniem w czasie zaplanowanych operacji oceanotechnicznych. W celu zapewnienia niezawodnej realizacji tak kosztownych operacji, różne rodzaje nadmiarowości są wprowadzane do projektowanej struktury siłowni okrętowej. W artykule omówiono zagadnienia związane z zastosowaniem redundancji w siłowniach okrętowych statków oceanotechnicznych. W szczególności zaś zaprezentowano ewolucję stosowania redundancji w siłowniach okrętowych oraz rozwiązania projektowe nadmiarowości zastosowane w siłowniach okrętowych statków oceanotechnicznych. Ponadto, omówiono szczegółowo specyfikę przeprowadzanych operacji oceanotechnicznych istotnych ze względu na minimalizację strat finansowych związanych z ewentualnymi przerwami spowodowanymi awariami systemów wytwarzania energii i napędu statków oceanotechnicznych.

EN

Power and propulsion systems of offshore units must be of a very high level of reliability. Loss of ability to perform functions of their components causes generally to very high economic losses, which may be increased by unused the weather window resulting to postponing the planned offshore operations. To ensure carrying out so expensive offshore operations in the most reliable way, various types of redundancies are built-in ship power plants. This paper deals with issues related to application of redundancy in ship power plants of offshore vessels. Especially, evolution of redundancy application in ship power plants and design solution of redundancy for offshore vessels are presented. Moreover, the specifics of these offshore operations so important from the point of view of minimizing financial losses due to any interruptions caused by failures of power and propulsion systems are discussed in detailed way.

18

Redundancja jako sposób zwiększenia niezawodności siłowni okrętowych

Tarełko W.

Przegląd Mechaniczny

|

2017

|

nr 11

54--59

PL

Jednym z istotnych sposobów zapewnienia wysokiego poziomu niezawodności siłowni okrętowych jest zaprojektowanie redundancji jego elementów strukturalnych, np.: nadmiarowości strukturalnej systemów generowania energii, układów napędowych itp. W niniejszym artykule omówiono zagadnienia związane z nadmiarem, jako sposobem zwiększenia niezawodności systemów generowania energii i napędu statku. W szczególności zaś zostały zaprezentowane podstawowe cechy niezawodności, główne strategie oddziaływania na niezawodność oraz rodzaje nadmiarowości w odniesieniu do systemów generowania energii i napędu statku.

EN

One of the key ways of assuring a high level of reliability of a ship power plant is to design redundancy of its structural elements, for example redundancy of prime drivers, drivelines etc. This paper deals with issues related to the redundancy as a way increasing dependability of the ship power and propulsion systems. Especially, fundamental characteristics of dependability, major design strategies which influence reliability, and types of redundancies related to ship power and propulsion systems are presented.

19

Water level control system for a boiler drum of a power boiler resistant to measuring track damage

Pawlak M.

Problemy Eksploatacji

|

2016

|

no. 2

135--144

EN

Design and operation methods of automated systems that tolerate measurement track damage are presented. This type of structure for feed water control systems in the drum boilers is described. The study presents a concept of an FTC (Fault Tolerant Control) system in the regulation system of the water level inside a drum. The creation and examination of partial models for the diagnostic system are described. Analytical redundancy has been applied in the presented regulation system. The effects of diagnostics and fault tolerance on the values of reliability and power block operational safety indexes have been determined in the study. Moreover, regulation systems in use are described and backup structures have been developed in order to create a regulation system that would be resistant to fault of the measurement tracks.

PL

Przedstawiono sposób projektowania i działania układów automatyki tolerujących uszkodzenia torów pomiarowych. Opisano układ tego typu dla systemu regulacji zasilania w wodę kotła walczakowego. Praca przedstawia koncepcję systemu FTC (Fault Tolerant Control) w układzie regulacji poziomu wody w walczaku. Opisano sposób tworzenia i badań modeli cząstkowych dla systemu diagnostycznego. W opisywanym układzie regulacji zastosowano redundancję analityczną. W pracy określono wpływ diagnostyki i tolerowania uszkodzeń na wartości wskaźników niezawodności i bezpieczeństwa pracy bloku energetycznego. Opisano także stosowane układy regulacji i opracowano struktury rezerwowe, aby powstał układ regulacji odporny na uszkodzenia torów pomiarowych.

20

Introducing probabilistic models for redundant system reliability

Babagana M., Gimba B., Yusuf I.

Operations Research and Decisions

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2016

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Vol. 26, No. 1

5--18

EN

Probabilistic models have been developed to evaluate the relationship between reliability measures and the performance of a repairable network with built in redundancy. Networks with built in redun-dancy have been considered and explicit expressions have been derived for three characteristics related to such systems including steady-state availability, period of repair, and a profit function. Various graphs have been plotted to discover the impact of availability and mean time to system failure on net profit, as well as the impact of the failure and service rate on the steady-state availability, net profit and mean time to system failure. The system was analysed using first order linear differential equations.