Research

18 pages, 1061 KiB

Open AccessFeature PaperArticle

The Reliability and Exploitation Analysis Method of the ICT System Power Supply with the Use of Modelling Based on Rough Sets

by Marek Stawowy, Adam Rosiński, Jacek Paś, Stanisław Duer, Marta Harničárová and Krzysztof Perlicki

Energies 2023, 16(12), 4621; https://doi.org/10.3390/en16124621 - 09 Jun 2023

Viewed by 979

Abstract

The article describes a new approach to the reliability–exploitation analysis of the critical information and communications technology (ICT) system power supply. A classic approach based on statistical indicators and a new one founded on uncertainty modelling based on the rough set method is [...] Read more.

The article describes a new approach to the reliability–exploitation analysis of the critical information and communications technology (ICT) system power supply. A classic approach based on statistical indicators and a new one founded on uncertainty modelling based on the rough set method is presented. The main advantage of the uncertainty modelling approach is the simplification of the calculations and the fact that, unlike statistical analysis, uncertainty modelling does not require complete information on the used data sets. An extensive study of world publications was carried out, proving that this is an entirely innovative approach to solving the problem of reliability and exploitation analysis. Calculations, analyses and syntheses are also exhibited in a specific example. A sample of the ICT system power supply was simulated, and the simulation results are shown. The simulations were prepared by one of the co-authors for the purposes of this article. Full article

(This article belongs to the Special Issue Modeling of Quality, Reliability, and Exploitation for Power Supply Systems, ICT Systems, and Transportation Systems)

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22 pages, 5568 KiB

Open AccessEditor’s ChoiceArticle

Formal Verification of the European Train Control System (ETCS) for Better Energy Efficiency Using a Timed and Asynchronous Model

by Andrzej Kochan, Wiktor B. Daszczuk, Waldemar Grabski and Juliusz Karolak

Energies 2023, 16(8), 3602; https://doi.org/10.3390/en16083602 - 21 Apr 2023

Cited by 2 | Viewed by 1490

Abstract

The ERTMS/ETCS is the newest automatic train protection system. This is a system that supports the driver in driving the train. It is currently being implemented throughout the European Union. This system’s latest specifications also provide additional functions to increase the energy efficiency [...] Read more.

The ERTMS/ETCS is the newest automatic train protection system. This is a system that supports the driver in driving the train. It is currently being implemented throughout the European Union. This system’s latest specifications also provide additional functions to increase the energy efficiency of train driving in the form of ATO (automatic train operation). These functions of the ETCS will be valuable, provided they operate without failure. To achieve errorless configuration of the ETCS, a methodology for automatic system verification using the IMDS (Integrated Model of Distributed Systems) formalism and the temporal tool Dedan was applied. The main contribution is asynchronous and timed verification, which appropriately models the distributed nature of the ETCS and allows the designer not only to analyze time dependencies but also to define the range of train velocities in which the operational scenario is valid. Additionally, the novelties of the presented verification methodology are the graphical design of the system components and automated verification freeing the designer from using textual design. We express the verified properties as observer automata rather than in temporal logic. Moreover, we check partial properties related to system fragments, which is crucial in distributed systems. This paper presents the verification of an example ETCS system application. The verification results are presented as sequence diagrams leading to a correct/incorrect final state. Full article

(This article belongs to the Special Issue Modeling of Quality, Reliability, and Exploitation for Power Supply Systems, ICT Systems, and Transportation Systems)

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31 pages, 7450 KiB

Open AccessArticle

Modelling the Operation Process of Light Utility Vehicles in Transport Systems Using Monte Carlo Simulation and Semi-Markov Approach

by Mateusz Oszczypała, Jarosław Ziółkowski and Jerzy Małachowski

Energies 2023, 16(5), 2210; https://doi.org/10.3390/en16052210 - 24 Feb 2023

Cited by 5 | Viewed by 1534

Abstract

This research paper presents studies on the operation process of the Honker 2000 light utility vehicles that are part of the Polish Armed Forces transport system. The phase space of the process was identified based on the assumption that at any given moment [...] Read more.

This research paper presents studies on the operation process of the Honker 2000 light utility vehicles that are part of the Polish Armed Forces transport system. The phase space of the process was identified based on the assumption that at any given moment the vehicle remains in one of four states, namely, task execution, awaiting a transport task, periodic maintenance, or repair. Vehicle functional readiness and technical suitability indices were adopted as performance measures for the technical system. A simulation model based on Monte Carlo methods was developed to determine the changes in the operational states. The occurrence of the periodic maintenance state is strictly determined by a planned and preventive strategy of operation applied within the analysed system. Other states are implementations of stochastic processes. The original source code was developed in the MATLAB environment to implement the model. Based on estimated probabilistic characteristics, the authors validated 16 simulation models resulting from all possible cumulative distribution functions (CDFs) that satisfied the condition of a proper match to empirical data. Based on the simulated operation process for a sample of 19 vehicles over the assumed 20-year forecast horizon, it was possible to determine the functional readiness and technical suitability indices. The relative differences between the results of all simulation models and the results obtained through the semi-Markov model did not exceed 6%. The best-fit model was subjected to sensitivity analysis in terms of the dependence between functional readiness and technical suitability indices on vehicle operation intensity. As a result, the proposed simulation system based on Monte Carlo methods turned out to be a useful tool in analysing the current operation process of means of transport in terms of forecasts related to a current environment, as well as when attempting its extrapolation. Full article

(This article belongs to the Special Issue Modeling of Quality, Reliability, and Exploitation for Power Supply Systems, ICT Systems, and Transportation Systems)

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Graphical abstract

26 pages, 3773 KiB

Open AccessArticle

Maximization of Energy Efficiency by Synchronizing the Speed of Trains on a Moving Block System

by Janusz Szkopiński and Andrzej Kochan

Energies 2023, 16(4), 1764; https://doi.org/10.3390/en16041764 - 10 Feb 2023

Cited by 4 | Viewed by 1074

Abstract

The publication deals with the problem of the effect of interference with the movement of the “preceding” train on the movement of the “following” train in the case of efforts to reduce the distance between trains on a moving block interval. The paper [...] Read more.

The publication deals with the problem of the effect of interference with the movement of the “preceding” train on the movement of the “following” train in the case of efforts to reduce the distance between trains on a moving block interval. The paper presents results of the simulations for train of the ED250 type for a set of 135 traffic situations: for three contexts of reducing the speed of the “preceding” train, for five variants of the method of controlling the “following” train and for nine initial distances between these trains. The results confirmed the possibility of gaining time and energy benefits by implementing an appropriate method of controlling the “following” train, as well as providing insights into the area of shortening the gaps between trains, including the pursuit of synchronizing the speed of trains and possibly coupling them into a so-called virtual couples. Full article

(This article belongs to the Special Issue Modeling of Quality, Reliability, and Exploitation for Power Supply Systems, ICT Systems, and Transportation Systems)

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13 pages, 1988 KiB

Open AccessArticle

Possibility of Marine Low-Speed Engine Piston Ring Wear Prediction during Real Operational Conditions

by Włodzimierz Kamiński and Iwona Michalska-Pożoga

Energies 2023, 16(3), 1433; https://doi.org/10.3390/en16031433 - 01 Feb 2023

Viewed by 1700

Abstract

A long-stroke, low-speed marine engine is used as the prime mover of a ship. During the operation of such engines, the excessive wear of the cylinder liners and piston rings frequently occurs. The breakdown of cylinder liners or piston rings is very dangerous [...] Read more.

A long-stroke, low-speed marine engine is used as the prime mover of a ship. During the operation of such engines, the excessive wear of the cylinder liners and piston rings frequently occurs. The breakdown of cylinder liners or piston rings is very dangerous for the safety of a vessel, the environment, and the people on board. The reliability of engine components is an extremely important topic, as it influences the efficient operation of the vessel. Therefore, to prevent such undesired events, it is essential that the condition of the cylinder liners and piston rings is frequently assessed. This paper presents research that finds prediction models for the rate of piston ring wear. The compiled prediction models are verified using verification tests. The models can be implemented to evaluate the tendency of piston rings to wear, and can be used to evaluate the quality of cylinder liner lubrication. Our findings will help to obtain the required optimal piston ring wear rates, maintain the good operational condition of the engine, reduce the costs of engine maintenance, and reduce the total consumption of lubricating oil and the emission of noxious substances into the atmosphere. All the mentioned benefits are related to a reduction in the ship’s operational costs and are directly related to energy efficiency. Full article

(This article belongs to the Special Issue Modeling of Quality, Reliability, and Exploitation for Power Supply Systems, ICT Systems, and Transportation Systems)

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15 pages, 3386 KiB

Open AccessArticle

Service Life Prediction for Rotating Electrical Machines on Aircraft in Terms of Temperature Loads

by Andrzej Żyluk, Mariusz Zieja, Justyna Tomaszewska, Mariusz Michalski and Krzysztof Kordys

Energies 2023, 16(1), 218; https://doi.org/10.3390/en16010218 - 25 Dec 2022

Cited by 1 | Viewed by 1076

Abstract

This article is focused on the research concerning the calculation of the durability of electrical machines installed in the electrical system of M-28 and C-130 Hercules aircraft. The article presents a method of predicting the service life of aircraft commutator machines, which are [...] Read more.

This article is focused on the research concerning the calculation of the durability of electrical machines installed in the electrical system of M-28 and C-130 Hercules aircraft. The article presents a method of predicting the service life of aircraft commutator machines, which are the primary source of electrical energy. The result of the research was the determination of the durability of bearings and coils of electrical machines operated on aircraft based on a flight profile analysis. It is problematic to directly measure the wear of bearings and windings of an electric machine on the aircraft. Their usage can be determined from the relation between their wear and the ambient temperature. This research can be used in practice to plan maintenance work on the analyzed aircrafts. Full article

(This article belongs to the Special Issue Modeling of Quality, Reliability, and Exploitation for Power Supply Systems, ICT Systems, and Transportation Systems)

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22 pages, 21384 KiB

Open AccessArticle

Construction of a Measurement System with GPS RTK for Operational Control of Street Lighting

by Piotr Jaskowski, Piotr Tomczuk and Marcin Chrzanowicz

Energies 2022, 15(23), 9106; https://doi.org/10.3390/en15239106 - 01 Dec 2022

Cited by 1 | Viewed by 1429

Abstract

Street lighting should realise normative illuminance levels throughout the roadway. The determination of the illuminance level of a road requires the use of a measurement technique based on classic point measurements at a specific grid of measurement points. Classical stationary measurements using the [...] Read more.

Street lighting should realise normative illuminance levels throughout the roadway. The determination of the illuminance level of a road requires the use of a measurement technique based on classic point measurements at a specific grid of measurement points. Classical stationary measurements using the method indicated in the prescriptive requirements are time-consuming and labor-intensive. The authors of the article have presented a concept of a measurement system that could be used to partially automate road lighting measurements and increase their universality. The proposed measurement system uses the simultaneous measurement of illuminance values from lux meters located on the roof of the vehicle. The measurement is carried out while the vehicle is driving on a lit road, and the illuminance values are localized using a global GPS satellite location system equipped with RTK corrections. The use of GPS RTK localization data corrections allowed the measurement results to be unambiguously assigned to post-measurement fields. On the basis of the collected measurement data, with the use of terrain maps, it is possible to determine in detail the illuminance parameters on the surveyed road sections. The paper presents the construction of a measurement system for the mobile measurement of street lighting intensity using a GPS RTK receiver, along with verification of its correct operation. The correctness of the system’s operation was confirmed on the basis of the Measurement System Analysis (MSA) method. The calculations performed confirmed an R&R result of 11.14%. The proposed solution allows data on the lighting parameters of the surveyed road section to be obtained in a quick and repeatable manner. As a result, it is possible to make a quick assessment of the street lighting condition of the entire road section. The proposed system has been verified under field conditions and the repeatability of the results obtained has been confirmed. Full article

(This article belongs to the Special Issue Modeling of Quality, Reliability, and Exploitation for Power Supply Systems, ICT Systems, and Transportation Systems)

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22 pages, 3774 KiB

Open AccessArticle

Temporal Verification of Relay-Based Railway Traffic Control Systems Using the Integrated Model of Distributed Systems

by Juliusz Karolak, Wiktor B. Daszczuk, Waldemar Grabski and Andrzej Kochan

Energies 2022, 15(23), 9041; https://doi.org/10.3390/en15239041 - 29 Nov 2022

Cited by 3 | Viewed by 1090

Abstract

Relay-based traffic control systems are still used in railway control systems. Their correctness is most often verified by manual analysis, which does not guarantee correctness in all conditions. Passenger safety, control reliability, and failure-free operation of all components require formal proof of the [...] Read more.

Relay-based traffic control systems are still used in railway control systems. Their correctness is most often verified by manual analysis, which does not guarantee correctness in all conditions. Passenger safety, control reliability, and failure-free operation of all components require formal proof of the control system’s correctness. Formal evidence allows certification of control systems, ensuring that safety will be maintained in correct conditions and the in event of failure. The operational safety of systems in the event of component failure cannot be manually checked practically in the event of various types of damage to one component, pairs of components, etc. In the article, we describe the methodology of automated system verification using the IMDS (integrated model of distributed systems) temporal formalism and the Dedan tool. The novelty of the presented verification methodology lays in graphical design of the circuit elements, automated verification liberating the designer from using temporal logic, checking partial properties related to fragments of the circuit, and fair verification preventing the discovering of false deadlocks. The article presents the verification of an exemplary relay traffic control system in the correct case, in the case of damage to elements, and the case of an incorrect sequence of signals from the environment. The verification results are shown in the form of sequence diagrams leading to the correct/incorrect final state. Full article

(This article belongs to the Special Issue Modeling of Quality, Reliability, and Exploitation for Power Supply Systems, ICT Systems, and Transportation Systems)

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26 pages, 7232 KiB

Open AccessArticle

Selected Issues Associated with the Operational and Power Supply Reliability of Fire Alarm Systems

by Tomasz Klimczak, Jacek Paś, Stanisław Duer, Adam Rosiński, Patryk Wetoszka, Kamil Białek and Michał Mazur

Energies 2022, 15(22), 8409; https://doi.org/10.3390/en15228409 - 10 Nov 2022

Cited by 4 | Viewed by 1960

Abstract

The article reviews issues associated with the use of electronic fire alarm systems (FAS). They are operated in various environments and buildings with varying volumes. FAS have to function properly under different operating conditions associated with their operation, as well as power supply [...] Read more.

The article reviews issues associated with the use of electronic fire alarm systems (FAS). They are operated in various environments and buildings with varying volumes. FAS have to function properly under different operating conditions associated with their operation, as well as power supply and information inflow. Due to their functions, i.e., ensuring the safety of people, vehicles, logistics bases, airports, etc., FAS have to exhibit an appropriately organized reliability structure associated with their implementation and power supply. Operational studies involving FAS operated in various facilities were conducted to this end. The authors determined damage and recovery time intensities. FAS reliability indicators were also determined. The article presents graphs associated with developing the energy balance for selected FAS. The graphs are consistent with the latest and applicable legal regulations. The next stage of the work related to this article was developing an FAS operation process model and conducting computer simulations in order to determine reliability indicators. Such an approach to the FAS operation process enables a rational selection of technical and organizational solutions aimed at guaranteeing reliability in the course of executing operational tasks associated with ensuring fire safety. FAS operational analysis, developing balance graphs and models, as well as the computer simulation, enabled inferring conclusions that might be useful to the process of engineering and operating such systems. Full article

(This article belongs to the Special Issue Modeling of Quality, Reliability, and Exploitation for Power Supply Systems, ICT Systems, and Transportation Systems)

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14 pages, 3287 KiB

Open AccessArticle

UTC Synchronized Signal Generation for Synchrophasors and Sampled Values Measurements

by Karol Makowiecki, Aleksander Lisowiec, Pawel Michalski and Marcin Habrych

Energies 2022, 15(19), 7095; https://doi.org/10.3390/en15197095 - 27 Sep 2022

Cited by 3 | Viewed by 1204

Abstract

This article describes two methods and circuits for generation of a signal synchronized to the Coordinated Universal Time (UTC) time scale. The signal is used as a sampling clock for a synchrophasor and Sampled Values generation. Both methods use a PPS (Pulse Per [...] Read more.

This article describes two methods and circuits for generation of a signal synchronized to the Coordinated Universal Time (UTC) time scale. The signal is used as a sampling clock for a synchrophasor and Sampled Values generation. Both methods use a PPS (Pulse Per Second) pulse as a synchronization signal. In the first method, the synchronization procedure is implemented entirely in a Field Programmable Gate Array (FPGA) device. The second method uses a microcontroller and a Temperature Compensated Voltage Controlled Crystal Oscillator (TCVCXO). The common feature of the presented methods is that they are cost effective and use a minimal number of components. This paper presents the implementation details of both methods as well as the measurement results, which show that the accuracy of the synchronized signals in both procedures makes them suitable for use in synchrophasors and sampled values measurements. Full article

(This article belongs to the Special Issue Modeling of Quality, Reliability, and Exploitation for Power Supply Systems, ICT Systems, and Transportation Systems)

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18 pages, 7819 KiB

Open AccessArticle

The Potential Impact of Laser Pointers on Aviation Safety

by Wojciech Wawrzyński, Mariusz Zieja, Justyna Tomaszewska, Mariusz Michalski, Grzegorz Kamiński and Dawid Wabik

Energies 2022, 15(17), 6226; https://doi.org/10.3390/en15176226 - 26 Aug 2022

Cited by 5 | Viewed by 1821

Abstract

Introduction: Although aviation is considered the safest mode of transportation, the annual number of pilots blinded by laser light cannot be understated. An analysis of the available statistics indicates that it is a widespread phenomenon. The stories told by the pilots show the [...] Read more.

Introduction: Although aviation is considered the safest mode of transportation, the annual number of pilots blinded by laser light cannot be understated. An analysis of the available statistics indicates that it is a widespread phenomenon. The stories told by the pilots show the consequences of these incidents, ranging from temporary sight loss to months of vision problems. The article also describes the current penalties for dazzling a pilot by laser light. Moreover, limited research has been conducted on the intensity of laser light of different wavelengths passing through the fairing and through standard glasses used by pilots. Understanding the effects of laser glare on pilots can help reduce adverse events and improve the ability of safety managers to develop safety procedures. Correctly designed transport systems enable effective route planning and order processing. Methods: Two types of easily available laser pointers, drawn at different distances from the aircraft, were analyzed and the intensity of the transmitted light was examined. Results: The results showed that the intensity decreases with distance and that the intensity is too low to harm the eye. In addition, it should not be forgotten that the light propagates in a cone which strengthens the illumination effect in the cabin and causes pilots to lose orientation. Practical application of the findings: They enable the identification of areas around the airport where the use of lasers should be prohibited. Practical Application: The possibility of determining the transition of laser light through the windscreen of the aircraft as well as its intensity under near real-life conditions. Full article

(This article belongs to the Special Issue Modeling of Quality, Reliability, and Exploitation for Power Supply Systems, ICT Systems, and Transportation Systems)

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22 pages, 4300 KiB

Open AccessArticle

Optimization of the Delivery Time within the Distribution Network, Taking into Account Fuel Consumption and the Level of Carbon Dioxide Emissions into the Atmosphere

by Jarosław Ziółkowski, Aleksandra Lęgas, Elżbieta Szymczyk, Jerzy Małachowski, Mateusz Oszczypała and Joanna Szkutnik-Rogoż

Energies 2022, 15(14), 5198; https://doi.org/10.3390/en15145198 - 18 Jul 2022

Cited by 6 | Viewed by 1518

Abstract

The evolution of changes in shopping in the modern society necessitates suppliers to seek new solutions consisting of increasing the efficiency of transport processes. When it comes to controlling the flow of goods in modern distribution networks, planning and timely deliveries are of [...] Read more.

The evolution of changes in shopping in the modern society necessitates suppliers to seek new solutions consisting of increasing the efficiency of transport processes. When it comes to controlling the flow of goods in modern distribution networks, planning and timely deliveries are of particular importance. The first factor creating a competitive advantage involves the tendency to shorten order delivery times, especially for products with a short shelf life. Shorter delivery times, in turn, extend the period of effective residence of the product “available on the shelf”, increasing the likelihood of its sale. The second component in line with the Sustainable Development Strategy consists of aspects related to the protection of the natural environment, in particular those related to car transport. In this case, the fuel consumption and the level of emitted toxic substances (including carbon dioxide) are analyzed and assessed. Bearing in mind the above, this article presents the problem of optimizing the delivery time within the assumed distribution network and its solution, enabling the company to develop and optimal plan for the transport of products with a short shelf life. The paper proposes a model that takes into account minimization of the delivery time, while estimating the values of fuel consumption and CO₂ emissions for the variants considered. The means of transport were medium-duty trucks. Three variants of the assumptions were considered, and algorithms implemented in MS Excel and MATLAB software were used to perform the optimization. Using the MATLAB environment, a more favorable value of the objective function was obtained for the variant without additional constraints. On the other hand, the algorithm implemented in MS Excel more effectively searched the set of acceptable solutions with a larger number of constraining conditions. Full article

(This article belongs to the Special Issue Modeling of Quality, Reliability, and Exploitation for Power Supply Systems, ICT Systems, and Transportation Systems)

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24 pages, 4120 KiB

Open AccessFeature PaperArticle

Analysis of Light Utility Vehicle Readiness in Military Transportation Systems Using Markov and Semi-Markov Processes

by Mateusz Oszczypała, Jarosław Ziółkowski and Jerzy Małachowski

Energies 2022, 15(14), 5062; https://doi.org/10.3390/en15145062 - 11 Jul 2022

Cited by 13 | Viewed by 1528

Abstract

This paper presents the issues of modeling the operation process of light utility vehicles operating in military transport systems. The required condition for the effective operation of the system is to maintain the means of transport at the appropriate level of technical readiness. [...] Read more.

This paper presents the issues of modeling the operation process of light utility vehicles operating in military transport systems. The required condition for the effective operation of the system is to maintain the means of transport at the appropriate level of technical readiness. For this purpose, it is necessary to equip the technical system with appropriate resources enabling the efficient implementation of fuel refilling, maintenance and repair processes. Each failure of the means of transport causes a significant reduction in transport capacity, which then results in the inability to perform the planned tasks. Quality control and vehicle operation process management require advanced mathematical methods and tools. Three indicators have been proposed as quantitative characteristics for assessing and optimizing the availability of military vehicles: functional readiness, technical efficiency and airworthiness. To determine their value, a stochastic exploitation model was developed based on the application of the theory of Markov processes. Based on the collected empirical data, a nine-state phase space of the studied process was identified. Operating states were distinguished relating to the implementation of the transport task, refueling, parking in the garage, as well as maintenance and repairs. As part of the considerations for the continuous time, verification of the distributions of time characteristics led to the development of a semi-Markov model. The ergodic probabilities calculated based on the conditional probability matrix of interstate transitions and the expected values of the time spent in the states were used to determine the indicators of functional availability, efficiency and technical suitability. In order to determine the possibility of optimizing the process, a sensitivity analysis was performed. Reducing the amount of time the vehicles must wait for repair by about 50% can improve the values of the indexes from 0.91 to 0.95. Full article

(This article belongs to the Special Issue Modeling of Quality, Reliability, and Exploitation for Power Supply Systems, ICT Systems, and Transportation Systems)

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30 pages, 5461 KiB

Open AccessArticle

Compressed Air Energy Storage Capacity Configuration and Economic Evaluation Considering the Uncertainty of Wind Energy

by Qihui Yu, Li Tian, Xiaodong Li and Xin Tan

Energies 2022, 15(13), 4637; https://doi.org/10.3390/en15134637 - 24 Jun 2022

Cited by 10 | Viewed by 1794

Abstract

The random nature of wind energy is an important reason for the low energy utilization rate of wind farms. The use of a compressed air energy storage system (CAES) can help reduce the random characteristics of wind power generation while also increasing the [...] Read more.

The random nature of wind energy is an important reason for the low energy utilization rate of wind farms. The use of a compressed air energy storage system (CAES) can help reduce the random characteristics of wind power generation while also increasing the utilization rate of wind energy. However, the unreasonable capacity allocation of the CAES system results in high capital investment and a long payback period. In order to improve the economic benefits of energy storage, this paper studies the capacity configuration of compressed air energy storage systems under the condition of wind energy uncertainty. First, the typical hourly power distribution of wind power generation was obtained using historical data. Factors such as user load demand, time-of-use price of the power grid, system investment cost, power shortage cost, and power sales revenue were considered. Then, a model was built with the charging and discharging power and gas storage capacity of the CAES system as constraints, and the maximum return on investment and the minimum volume of the gas storage tank as targets. NSGA-II and TOPSIS optimal selection methods were used to solve the problem. Finally, the model was used to optimize a power operation case. The results show that in the case of an hourly load power demand of a factory using 3.2 MW, a wind farm would need to keep four wind turbines running every day, and a compressed air energy storage system with a rated power of 1 MW and a rated capacity of 7 MW would ensure the best project benefit. In this mode, 1.24 × 10³ MWh of wind abandoning power could be reduced annually, 2.6 × 10⁴ kg of carbon emissions could be reduced by increasing energy storage within the operation cycle, and the payback period of investment would only be 4.8 years. Full article

(This article belongs to the Special Issue Modeling of Quality, Reliability, and Exploitation for Power Supply Systems, ICT Systems, and Transportation Systems)

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34 pages, 29661 KiB

Open AccessArticle

Assessment of Explosion Safety Status within the Area of an LNG Terminal in a Function of Selected Parameters

by Agnieszka Magdalena Kalbarczyk-Jedynak, Magdalena Ślączka-Wilk, Magdalena Kaup, Wojciech Ślączka and Dorota Łozowicka

Energies 2022, 15(11), 4057; https://doi.org/10.3390/en15114057 - 31 May 2022

Cited by 1 | Viewed by 1528

Abstract

This paper examines the issues of designing optimization tasks with the objective of ensuring the safety and continuation of transportation processes. Modelling the processes that are a consequence of a breakdown is a crucial issue enabling an increase of safety at selected stages [...] Read more.

This paper examines the issues of designing optimization tasks with the objective of ensuring the safety and continuation of transportation processes. Modelling the processes that are a consequence of a breakdown is a crucial issue enabling an increase of safety at selected stages of transport. This paper elaborates on the matter of modelling hazardous situations resulting from an uncontrolled LNG release due to a crash or damage to a ship’s hull. This paper demonstrates subsequent stages of modelling along with theoretical assumptions and finally it presents the results of simulation calculations for various scenarios of LNG releases. The article shows the complexity of modelling at a time when variable atmospheric conditions occur, which hinder the planning of rescue operations in the event of an uncontrolled LNG release into the atmosphere. It needs to be remembered that making decisions in critical situations and developing proper procedures at a time when people’s lives are at risk or in the face of an environmental pollution incident constitutes one of the most significant components of effective management in transport. Two LNG release scenarios are presented in this article: catastrophic rupture and leak, for which danger zone dimensions were calculated. Simulations were conducted with the use of a tool called Phast ver. 8.23 for LNG. Calculations were made in a function of variable weather conditions and for two values of Pasquill coefficients. Full article

(This article belongs to the Special Issue Modeling of Quality, Reliability, and Exploitation for Power Supply Systems, ICT Systems, and Transportation Systems)

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18 pages, 1598 KiB

Open AccessArticle

The Issue of Evaluating the Effectiveness of Miniature Safety Fuses as Anti-Damage Systems

by Jarosław Łukasiak, Adam Rosiński and Michał Wiśnios

Energies 2022, 15(11), 4013; https://doi.org/10.3390/en15114013 - 30 May 2022

Cited by 3 | Viewed by 1370

Abstract

The objective of this article was to determine, in practice, whether the break time t_w of safety fuses can impact the security level provided by electronic security systems (ESSs) that utilize the aforementioned elements as their components. This was the purpose of [...] Read more.

The objective of this article was to determine, in practice, whether the break time t_w of safety fuses can impact the security level provided by electronic security systems (ESSs) that utilize the aforementioned elements as their components. This was the purpose of the conducted destructive testing aimed at estimating the break times for a certain random number of glass tube, miniature 5 × 20 (mm) fuse links with rapid operating characteristics, without a quenching medium and with a rated overcurrent intensity of 0.5 (A) by the selected manufacturers. For this purpose, a dedicated measuring attachment that enables forcing the flow of overcurrents with selected intensities in the range of 1.5 ÷ 11.5 (A) through the studied fuse links has been developed. The obtained results showed that the ratio of the break times between the best and the worst products in the entire tested range of overcurrents ranges from 5.41 (for 3.5 (A)) to 7.80 (at an overcurrent of 9.5 (A)). Statistical analysis of the measurement uncertainties proved that the obtained results of the break time do not depend on the applied research methodology or measuring equipment but are almost exclusively the result of the manufacturing spread of the tested components. Interestingly, the economic analysis did not bring clear conclusions. In this case, the products with the worst break time t_w turned out to be almost three times cheaper than the best fuse-links. What is more, the collective packaging of the product that turned out to be the best was cheaper than the next one in the list by almost USD 2.00. Full article

(This article belongs to the Special Issue Modeling of Quality, Reliability, and Exploitation for Power Supply Systems, ICT Systems, and Transportation Systems)

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29 pages, 15799 KiB

Open AccessArticle

Experimental and Numerical Investigations of Bird Models for Bird Strike Analysis

by Janusz Ćwiklak, Ewelina Kobiałka and Artur Goś

Energies 2022, 15(10), 3699; https://doi.org/10.3390/en15103699 - 18 May 2022

Cited by 11 | Viewed by 2402

Abstract

The article presents experimental and numerical studies of bird models during impacts with rigid and deformable targets. The main aim of the studies is the validation of bird models in order to prepare them for the numerical simulation of bird impact against aircraft [...] Read more.

The article presents experimental and numerical studies of bird models during impacts with rigid and deformable targets. The main aim of the studies is the validation of bird models in order to prepare them for the numerical simulation of bird impact against aircraft windshields and other parts of aircraft, thus improving the air transportation safety by providing cost-effective solutions for designing bird strike-resistant aircraft. The experimental investigations were conducted with a special set-up of a gas gun equipped with high-speed cameras, tensiometers and force sensors. The simulations were developed on the basis of LS-DYNA software by means of the SPH method for the bird model shape of the cylinder with hemispherical endings at the speed of 116 m/s. The results of studies into such things as the impact force, pressure and bird model deformation were compared. Moreover, the authors’ and other researchers’ results were assessed. It can be noted that the curves of the impact force obtained as a result of the numerical analysis correlated well with the experimental ones. Full article

(This article belongs to the Special Issue Modeling of Quality, Reliability, and Exploitation for Power Supply Systems, ICT Systems, and Transportation Systems)

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23 pages, 3950 KiB

Open AccessArticle

Assessing the Operation System of Fire Alarm Systems for Detection Line and Circuit Devices with Various Damage Intensities

by Jacek Paś, Adam Rosiński, Michał Wiśnios and Marek Stawowy

Energies 2022, 15(9), 3066; https://doi.org/10.3390/en15093066 - 22 Apr 2022

Cited by 6 | Viewed by 2730

Abstract

The paper presents a method for assessing operation processes for Fire Alarm Systems (FAS) applied in civil structures, based on use analysis. Individual FAS devices include components with varying ‘lifetimes’ and damage intensities λ. This is because these elements are operated in [...] Read more.

The paper presents a method for assessing operation processes for Fire Alarm Systems (FAS) applied in civil structures, based on use analysis. Individual FAS devices include components with varying ‘lifetimes’ and damage intensities λ. This is because these elements are operated in different internal and external environments. Probability distributions with various damage λ and recovery µ intensity values must, hence, be taken into account for the FAS operation process and to determine the R(t) reliability. The life cycle of elements comprising a FAS can be divided into three distinguishing time periods. The first is the so-called ‘childhood’. The second, the longest, is characterized by damage intensity λ = const, and the third period is where FAS is unfit more frequently. Based on knowledge of actual FAS operation process data, it is possible to determine damage λ and recovery µ intensity parameters. Such data can be employed to determine FAS reliability parameters within the presented service life intervals. The authors of the article first discuss the basic issues associated with FAS, followed by analyzing the current status of the topic. They also present power supply matters and system solution examples, develop an operation process model and determine selected operational indicators for the structures in question. The paper ends with conclusions. Full article

(This article belongs to the Special Issue Modeling of Quality, Reliability, and Exploitation for Power Supply Systems, ICT Systems, and Transportation Systems)

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