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EN
When comparing the performance indicators of electrical networks with different types of neutral grounding, along with the fulfilment of the requirement to ensure reliability of power supply to consumers, serious attention is drawn to the main network parameters influencing the performance of power supply systems. Analysis of research and its results, reported above, on the influence of the neutral ground of power networks on the reliability and electrical safety conditions of the power supply systems as a whole, on the damage of distribution networks and electrical equipment as well as on the working capacity of relay protection devices, provides an opportunity to estimate each specific operation mode of the neutral and to develop recommendations aimed at strengthening the positive indicators of the corresponding modes. Other things being equal, reliability of power supply to electrical receivers or reliability of distribution networks is mainly determined by the damage to network elements and the performance of relay protection devices. The degree of influence of these factors on the reliability of distribution networks depends on the neutral mode, which in turn determines the level of internal overvoltages and the nature of transient processes at earth fault.
2
Content available Port oil terminal reliability optimization
EN
A method for reliability optimization, which is relevant for critical infrastructure activity governed by operational processes, is presented and applied to a port oil terminal. The optimal values for the reliability and resilience indicators related to the operation, are determined for this critical type of infrastructure. Simple suggestions regarding optimized infrastructural operation strategies are formulated and implemented towards reorganizing the port oil terminal processes in order to maximize its lifetime in defined reliability states.
EN
In this paper the LNG carrier with steam turbine propulsion plant maintenance records has been analysed. Actual observed data from the ship, built in 2001, are from ship maintenance history data from September 2002 until August 2010. During the analysed period, main propulsion turbine had one major failure and several minor failures. The ship had three dry docks and one was prolonged due to increased requirements for cargo transport. Total running hours of the main propulsion turbine in the observed period of time were 63204 hours. The list of failures and influence of each mentioned failure of main turbine propulsion machinery is discussed and analysed in respect to the propulsion autonomy of the vessel.
PL
Krajowy system energetyczny zmienia w ostatnich latach swoją strukturę. Wynika to z naturalnych procesów zużycie skutkujących koniecznością wycofywania z eksploatacji starych bloków energetycznych i zastępowania ich nowymi źródłami. Drugim istotnym motywem zmian jest polityka klimatyczna Unii Europejskiej wymuszająca zastępowanie bloków węglowych odnawialnymi źródłami energii. Udział źródeł odnawialnych w produkcji energii systematycznie rośnie, ale o niezawodności dostaw energii decydują przede wszystkim źródła stabilne, czyli obecnie bloki węglowe. Z uwagi na fakt, że rolę bilansującą system będą one pełnić jeszcze co najmniej kilkanaście lat, ich niezawodność i dyspozycyjność będą decydowały o niezawodności całego systemu. W artykule omówiono zmianę struktury krajowego systemu energetycznego w ostatnich dziesięciu latach. Przeanalizowano również zmianę wskaźników awaryjności i dyspozycyjności bloków węglowych. Oszacowano poziomy mocy możliwe do pokrycia przez źródła zainstalowane w krajowym systemie energetycznym.
EN
The national energy system has changed its structure in recent years. This is due to natural wear processes resulting in the need to decommission old power units and replace them with new sources. The other important motive for changes is the European Union's climate policy forcing the replacement of coal units with renewable energy sources. The share of renewable sources from energy production is steadily growing, but the reliability of energy supplies is primarily determined by stable sources, i.e. currently coal units. Due to the fact that they will perform the balancing role of the system for at least a dozen or so years, their reliability and availability will determine the reliability of the entire system. The article discusses the change in the structure of the national energy system in the last ten years. The change of failure rates and availability of coal units was also analysed. The power levels that could be covered by the coal sources installed in the national energy system were estimated.
EN
In this paper the analysis of electric systems' structures in nuclear power plants with emphasis on ensuring the operational reliability has been prepared. The authors focused on different issues regarding necessary conditions of a safe work of nuclear power plant. Based on authors research the auxiliaries’ power supply systems must be designed to assure a maximal reliability level of the supply for the most important auxiliaries. In the nuclear power plant, it is necessary to remove the decay heat produced in nuclear fuel during the long time after the reactor shutdown. It is also necessary to supply the devices responsible for the radiation protection of people and environment. The authors analyzed the categories of the nuclear power plant auxiliaries and the standards for qualifying electrical equipment for nuclear power plants. Electric part of nuclear power plant is a set of electric power equipment, interconnected using the electric current paths, designed to leading-out energy from the power plant to the electric power system (power leading-out system) and to supply auxiliaries (auxiliaries’ power supply system). The tasks of auxiliaries’ power supply system in normal conditions differ significantly from the tasks that this system satisfies in the transient conditions: starts-up, shut-downs and failures. The other thing is presented review of solutions of auxiliaries’ power supply in currently developed plants. The paper presents the solutions of auxiliaries’ power supply system in chosen power plants, which are presently design and/or in construction process.
PL
W artykule dokonano analizy struktur układów elektrycznych w elektrowniach jądrowych, ze szczególnym uwzględnieniem zapewnienia niezawodności operacyjnej. Autorzy skupili się na różnych zagadnieniach dotyczących niezbędnych warunków bezpiecznej pracy elektrowni jądrowej. Układy zasilania potrzeb własnych muszą być projektowane tak, aby zapewnić maksymalny poziom niezawodności zasilania najważniejszych odbiorników potrzeb własnych. W elektrowni jądrowej konieczne jest usuwanie ciepła wytwarzanego w paliwie jądrowym przez długi czas po wyłączeniu reaktora. Konieczne jest również zasilanie urządzeń odpowiedzialnych za ochronę radiologiczną ludzi i środowiska. Autorzy przeanalizowali kategorie urządzeń potrzeb własnych elektrowni jądrowej oraz standardy kwalifikowania urządzeń elektrycznych dla elektrowni jądrowych. Część elektryczna elektrowni jądrowej to zespół urządzeń elektroenergetycznych, połączonych torami prądowymi, przeznaczony do wyprowadzenia energii z elektrowni do systemu elektroenergetycznego (układ wyprowadzenia mocy) oraz do zasilania potrzeb własnych (układ zasilania potrzeb własnych). Zadania układu zasilania potrzeb własnych w normalnych warunkach znacznie odbiegają od zadań, które spełnia ten układ w warunkach przejściowych: rozruchy, wyłączenia i awarie. Kolejnym elementem artykułu jest przegląd rozwiązań zasilania potrzeb własnych w obecnie budowanych elektrowniach jądrowych. W artykule przedstawiono rozwiązania układów zasilania potrzeb własnych w wybranych elektrowniach, które są obecnie projektowane i / lub budowane.
EN
Nuclear power plants play an important role in power systems of many countries. Ability to reasonable increase installed capacity of nuclear power units allow to reduce the cost for building of new power plants. When increasing NPP capacity to 104% there is a need to estimate the residual life of plant’s typical elements and continue their operation. The mathematical model of estimation of service life indicators of steam turbine K-1000-60/3000 is developed. The effect of increasing the capacity of a nuclear reactor on the heat transfer coefficients of a steam in the nozzle segments of high-pressure cylinder was established by using CFD modeling. The thermal and stress-strain state of the high-pressure rotor for the most typical operating modes are calculated. Using the correlation dependences of low-cycle fatigue, the rate of accumulation of cyclic damage of the base metal is established. The resistance of the metal to the exhaustion of long-term strength is also determined. On the example of the high pressure rotor of the 3rd power unit of Rivne NPP the service life indicators are calculated. The validity of increasing the installed capacity of the power unit was also confirmed.
EN
Machine failures in each production system cause an increase in costs and delays in order execution. Therefore, companies decide to introduce solutions that detect and immediately remove worrying symptoms before more serious consequences occur. Unfortunately, not all failures can be avoided – in such cases, the most important thing is the quick reaction of machine operators, maintenance and production managers. This paper identifies reliability indicators and presents the steps and effects of implementing selected KPIs (Key Performance Indicators), which aim at the production process. For the machines in which a failure occurred in the surveyed period, technical availability, Mean Times Between Failures (MTBF), Mean Down Time (MDT), technical object readiness, and the downtime coefficient were calculated.
PL
Omówiono najczęściej występujące zaburzenia elektromagnetyczne, które mają wpływ na poprawność działania urządzeń elektrycznych wykorzystywanych w przemyśle chemicznym. Wyjaśniono pojęcie kompatybilności elektromagnetycznej urządzeń elektrycznych i przedstawiono możliwe skutki oddziaływania pól elektromagnetycznych. Dokonano przeglądu metod badania odporności urządzeń przeciwpożarowych, które odgrywają fundamentalną rolę w procesie zapewnienia bezpieczeństwa w przemyśle chemicznym.
EN
A review, with 20 refs., of common electromagnetic disturbances that affect the correct operation of elec. devices used in chem. industry and the methods for testing the immunity of fire protection devices which play a fundamental role in ensuring safety in the chem. industry.
EN
An investigation of the Mosul reservoir system within the Tigris river basin in Iraq was conducted to determine the ability of the system to generate hydroelectric power. A reproduction model utilizing the Simulink environment on the MATLAB platform was used to imitate the Mosul reservoir system. The reliability of the system under various future scenarios of data sources was also examined by employing a stochastic model used to create an inflow time series. The Thomas–Fiering model was chosen for this reason, which provided a wide range of data sources (inflows) to generate hydropower from the reservoir system under examination. Generally, the annual potential capacity of the Mosul basin for energy generation reaches 20,000 GW·h–1. Realizing that Iraq’s energy requirements are approximately 12 GW of power, and the integrating power production of the basin under examination is about 1.5 GW, this would cover around 12% of the total demand, which is significant.
10
Content available remote Optimal allocation of the electrical structure design using the bats approach
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.
PL
W artykule syntetycznie zaprezentowano analizę zmienności oraz rozrzuty wartości wskaźników SAIDI, SAIFI i MAIFI pięciu krajowych Operatorów Systemu Dystrybucyjnego za lata 2012-2018. Obliczenia przeprowadzono w środowisku R z zastosowaniem nieparametrycznych metod analizy danych. Graficzną prezentację wyników przedstawiono na wykresach pudełkowych. Przedstawiono również wybrane zagadnienia związane ze zmianami w modelu regulacji jakościowej. Artykuł zakończono uwagami dotyczącymi modelu regulacji jakościowej.
EN
The paper presents synthetically the analysis of variability and dispersion of the SAIDI, SAIFI and MAIFI indicators of the five national Distribution System Operators for the years 2012-2018. Calculations were performed in the R environment using non-parametric data analysis methods. Graphic performance of results is presented on box plots. Selected issues related to changes in the quality regulation model were also presented. The paper ends with comments on the quality regulation model.
EN
Our national security, economic prosperity and national welfare depend on a set of highly interdependent elements of critical infrastructure. Examples of critical infrastructure facilities include the national electricity grid, oil and gas systems, telecommunication and information networks, transportation networks, water systems and banking and financial systems. Given their importance, it is crucial to maintain the reliability of critical infrastructure facilities, especially power plants, both in times of peace and also in times of crisis or under conditions of attack. For this purpose, on the one hand, it is possible to improve and create new technical solutions supporting the restoration of the proper functioning of critical infrastructure facilities, such as remotely controlled mobile robots for example. On the other hand, it is important to prepare employees to operate in unusual conditions by organising appropriate training. In both cases, it can be useful to apply virtual reality techniques.
PL
Nasze bezpieczeństwo narodowe, dobrobyt gospodarczy i dobrobyt narodowy zależą od zestawu wysoce zależnych od siebie infrastruktur krytycznych. Przykładem obiektów infrastruktury krytycznej jest krajowa sieć elektryczną, systemy naftowe i gazowe, sieci telekomunikacyjne i informacyjne, sieci transportowe, systemy wodne oraz systemy bankowe i finansowe. Biorąc pod uwagę ich znaczenie kluczowe jest zachowanie niezawodności obiektów infrastruktury krytycznej, zwłaszcza elektrowni, również w warunkach kryzysowych lub ataku. W tym celu z jednej strony mogą być udoskonalane i tworzone nowe rozwiązania techniczne wspomagające przywrócenie prawidłowego funkcjonowania obiektów infrastruktury krytycznej, takie jak np. zdalnie sterowane roboty mobilne. Z drugiej ważne jest aby przygotować pracowników do działania w nietypowych warunkach organizując odpowiednie szkolenia. W obu przypadkach przydatne może okazać się zastosowanie technik rzeczywistości wirtualnej.
EN
In the period of shortage of gas supply, special attention is given to reducing the supply of gas to its consumers, that is, their complete and uninterrupted gas supply. Increasing gas losses associated with technological transportation costs, in particular caused by gas flow instability and frequent changes in gas transmission network operating modes. Considering losses due to unreliability of gas pumping is one of the important tasks of gas supply optimization. The purpose of the study is to develop an optimization mathematical model that will simultaneously take into account the factors of reliability and minimum lossesIn the general case, the optimization calculations of the modes of operation of the main gas pipelines are intended to solve three main problems: determining the maximum productivity, calculating the optimal mode with a given productivity and choosing the optimal strategy, the development of the pipeline. On the basis of approaches of simulation modeling of complex systems, a multiparameter mathematical model of gas supply process optimization was developed. It is shown that a comparative analysis of the forecast and actual indicators of the operating modes of the plunger gas pumping unit shows their satisfactory convergence. The performance of the compressor operation period in the process of injection according to the forecast deviates from the actual value for the whole period of operation of the plunger gas pumping unit in 2016 by 2.98%. The optimization problem of gas pumping planning is considered, taking into account the expected losses, on the basis of which the transfer of the controlled system from the initial state to the final one is carried out by such a sequence of states that minimizes the total cost of the system evolution.
EN
Reservoirs have a very important function in providing multi-sector water requirements. In the future, reservoirs not only serve to store and available water can also be used as disaster mitigation instruments. The completeness of hydrological measurements in reservoirs can be expanded more widely for climate change mitigation. The reliability of the reservoir capacity varies greatly depending on the El-Nino character that occurs among them El-Nino is weak, moderate, strong and very strong. The El-Nino characteristic is very influential on the period of water availability, the increase of evaporation capacity and decrease of reservoir capacity. Analysis of the reliability of the reservoir volume due to El-Nino using the Weibull equation. The deficit reservoir was calculated using the concept of water balance in the reservoir that is the relationship between inflow, outflow, and change of storage at the same time. Based on the results of the analysis showed that the evaporation increase and the decrease of reservoir capacity had a different pattern that is when the evaporation capacity started to increase at the same time the reservoir capacity decreased significantly. The correlation coefficient between evaporation capacity increase and decrease of reservoir water capacity are consecutively –0.828, –0.636, and –0.777 for El- Nino weak, moderate and very strong respectively. At the reservoir capacity reliability of 50% reservoir has a significant deficit. When weak El-Nino the deficit is 2.30∙106 m3, moderate: 6.58∙106 m3, and very strong 8.85∙106 m3.
EN
The paper presents an example of reliability analysis of shell structures susceptible to stability loss from the condition of node snapping. In the reliability analysis of the structure, uncertain parameters of the task are represented by uncorrelated random variables. The approach used in the paper is an extension of the idea, which assumes the use of Neural Networks (NNs) in Monte Carlo (MC) simulations to analyze the reliability of the structure. For this purpose, it was necessary to build a simple hybrid system formed with the two independent sequentially working Finite Element Method (FEM) and Neural Networks applications.
16
Content available remote Impact of the cargo customs complex efficiency on the supply chain reliability
EN
Creating supply chain involving the customs infrastructure facilities is an urgent topic when shipping cargo internationally. The most in demand are cargo customs complexes, which have in their structure customs storerooms, warehouses of temporary storage, perform freight-forwarding, and customs-brokerage and other functions that are necessary to perform foreign economic activity. Also there are subdivisions of customs authorities on their territory. This type of business activity provides the business entities with the comprehensive service and enables them to reduce the time spent moving to each of the necessary control services or logistics facilities when moving cargoes in different customs regimes. Therefore, it is proposed to apply the concept of logistics chain reliability with a freight customs complex as its element. The latter will take into account business entities` financial and time expenditures with non-productive timing at the different transition stages of material flow, and will enable to optimize information flows. The paper considers the procedure of placing imported goods in a temporary storage warehouse. It is proposed the regulation methodology for individual service stages provided by a freight customs complex. The generalized algorithm for constructing a reliability model of a freight customs complex`s operation is offered allowing to determine the reliability level of each individual element in a logistics chain.
EN
The paper presents the application of the CREAM (Cognitive Reliability and Error Analysis Method) method to assess operator reliability in the backwashing of filters process at the Water Treatment Station. For this purpose, two operators were surveyed. Based on the results, the human error probability was determined, which in both cases ranges from 5∙10-5 to 1∙10-2 . The results also indicate that the surveyed operators have extensive work experience and high qualifications.
PL
W artykule przedstawiono zastosowanie metody CREAM (ang. Cognitive Reliability and Error Analysis Method) do oceny niezawodności operatora podczas płukania filtrów na stacji uzdatniania wody. W tym celu badaniom poddanych zostało dwóch operatorów. Na podstawie wyników określono prawdopodobieństwo popełnienia błędu przez operatorów, które w obu przypadkach wynosi od 5∙10-5 do 1∙10-2. Wyniki wskazują również na duże doświadczenie oraz wysokie kwalifikacje badanych operatorów.
EN
The paper presents the developed simulation model enabling the evaluation of the reliability of technical objects, which in the process of operation is subjected to several different groups of factors causing their failures. Probability distributions of failures resulting from wear and random factors are used in the developed model to estimate the time of operation of the elements and the reliability of the system. The developed model together with the appropriate computer program is a tool of significant importance for design and operational practice. It enables decision-makers to estimate the reliability of elements and the whole system before the beginning of their operation.
PL
W artykule przedstawiono opracowany model symulacyjny umożliwiający ocenę niezawodności obiektów technicznych, które w procesie eksploatacji podlegają kilku różnym grupom czynników powodujących ich uszkodzenia. Rozkłady prawdopodobieństwa uszkodzeń wynikających ze zużycia i czynników losowych są w opracowanym modelu wykorzystywane do prognozowania czasu pracy elementów i niezawodności układu. Model ten wraz z odpowiednim programem komputerowym stanowi narzędzie o istotnym znaczeniu dla praktyki projektowej i eksploatacyjnej. Umożliwia decydentom szacowanie niezawodności elementów oraz całego układu jeszcze przed rozpoczęciem jego eksploatacji.
19
Content available remote Reliability determination of nanoelectronic devices using semi-Marcov processes
EN
The main purpose of the article is to investigate the reliability process of nanoelectronics devices. Firstly, the research problem is presented based on foreign data source. Then, the analytical method has been chosen – semi-Marcov processes. Next, according to the adopted method and input data, the operating process has been analyzed. Finally, the probabilities of objects being in particular operating states, e.g. in the state of failure-free operation have been determined.
PL
W artykule badany jest proces niezawodności urządzeń nanoelektronicznych. Na początku przedstawiono problem badawczy, w oparciu o zagraniczne źródła danych. Następnie dobrano metodę analityczną – procesy półmarkowowskie. W kolejnej części, bazując na przyjętej metodzie i danych wejściowych, przeanalizowano proces eksploatacji, wyznaczając prawdopodobieństwa przebywania obiektów w poszczególnych stanach eksploatacyjnych, np. w stanie bezawaryjnej pracy.
EN
The purpose of this paper is to determine the impact of using ferro-oil with 2% or 8% concentration of the magnetic particles as the lubricant of the slide journal bearing on its operating parameters regarding the reliability aspect. There has been presented an analytical and numerical calculation model based on experimentally determined physical quantities describing the dependence of viscosity of ferro-oil on fundamental parameters in the paper. Numerical calculations were performed by solving the Reynold’s type equation using the finite difference method using Mathcad 15 and own calculation procedures.
PL
Celem niniejszej pracy jest określenie jaki wpływ na zmianę parametrów eksploatacyjnych łożyska ślizgowego w aspekcie niezawodności może mieć zastawanie jako środka smarnego ferro-oleju o 2% lub 8% stężeniu cząstek magnetycznych. W pracy został przedstawiony analityczno-numeryczny model obliczeniowy bazujący na eksperymentalnie wyznaczonych fizycznych wielkościach opisujących zależność lepkości ferro-oleju od zmian podstawowych parametrów pracy. Obliczenia numeryczne wykonano rozwiązując równania typu Reynoldsa metodą różnic skończonych przy wykorzystaniu program Mathcad 15 i własnych procedur obliczeniowych.
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