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Journal articles on the topic 'Abnormal operation modes'
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1
Lili, Qu, Zhang Bo, and Wallace K. S. Tang. "Sneaking Operation Modes in Zero-Current-Switching Converter." Open Electrical & Electronic Engineering Journal 9, no. 1 (April 17, 2015): 127–34. http://dx.doi.org/10.2174/1874129001509010127.
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This paper reports the occurrence of some abnormal operational modes in soft-switching converters. By constructing a Boolean matrix based on the states of the switching components, some unexpected topological states are identified. Consequently, these states excite the abnormal or sneaking operational modes as referred. A three-stage step-up zero- current switching converter is used as an illustrative example and detailed analysis has been carried out. The phenomenon has also been confirmed in experiences, where performance degradation is noticed.
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Bovsunovskii, A. P. "Torsional vibrations in steam turbine shafting in turbogenerator abnormal modes of operation." Strength of Materials 44, no. 2 (March 2012): 177–86. http://dx.doi.org/10.1007/s11223-012-9370-9.
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Abd, Moaed A., Iker Gonzalez, Craig Ades, Mehrdad Nojoumian, and Erik D. Engeberg. "Simulated robotic device malfunctions resembling malicious cyberattacks impact human perception of trust, satisfaction, and frustration." International Journal of Advanced Robotic Systems 16, no. 5 (September 1, 2019): 172988141987496. http://dx.doi.org/10.1177/1729881419874962.
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Robot assistants and wearable devices are highly useful; however, these artificial systems are susceptible to hackers. In this article, two sets of experiments were conducted. The first part of this study simulated a malicious attack on a prosthetic arm system to adversely affect the operation of the prosthetic system, while the perception of 10 human subjects was surveyed. These 10 able-bodied subjects controlled the prosthetic arm and hand with electromyogram signals, while an artificial sensation of touch was conveyed to their arms as they operated the system, which enabled them to feel what the prosthetic hand was grasping as they were asked to transport an object from one location to another. This haptic feedback was provided in both the normal and abnormal operational modes but was disabled in the extremely abnormal mode. The electromyogram control signals for the arm were reversed in both the abnormal and extremely abnormal modes. Results from the simulated malicious attack on a prosthetic arm system showed that the subjects found the haptic feedback helpful in both the normal and abnormal modes of operation. Both the abnormal and extremely abnormal modes of operation negatively impacted the self-reported levels of trust, satisfaction, and frustration with the prosthetic system as the subjects grasped and transported an object. While these metrics were negatively impacted by system malfunctions resembling a malicious attack on the control functionality, it was possible to rebuild them to their former higher levels after the functionality of the prosthetic system was restored. A parallel study in this article involved simulating a malicious attack on a robot assistant to unfavorably affect the delivery operation modes, while the perception of 20 human subjects was surveyed. Results showed that the simulated malfunctions unfavorably impacted the perception of trust, satisfaction, and frustration, but it was possible to restore these metrics in two different ways as the device functionality was restored.
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Kryukov, Oleg, Igor Gulyaev, and Dmitriy Teplukhov. "Ensuring of Energy-Efficient Operating Modes of Electric-Driven Gas-Pumping Units." Известия высших учебных заведений. Электромеханика 65, no. 1 (2022): 42–48. http://dx.doi.org/10.17213/0136-3360-2022-1-42-48.
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The modern technologies and technical means providing energy efficient modes of natural gas pumping through main gas pipelines are considered. According to statistics, the main reasons for the high energy consumption of compressor stations are: deviations of the gas pipeline operating modes from the design, changes in the charac-teristics of technological units, unsatisfactory equipment condition, abnormal load distribution between work-shops and individual electric drives. It is shown that the traditional scheme of operation of unregulated gas com-pressor units leads to an overconsumption of electricity by 8 – 15 % in comparison with the operation in the de-sign mode. It is proposed to use the group connection of frequency-controlled electric-driven gas-pumping units in compressor workshops with high-voltage frequency converters. It is shown that the coordination of the operat-ing modes of all units within the compressor workshops with a decrease in the productivity of the gas pipeline by 5 % of the nominal with the help of frequency regulation allows saving up to 1.05 MW of power consumption, and at 10 % - more than 1.74 MW per year.
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Xu, Jin Jin, Zhong Wen, Kai Feng Zhang, Zheng Gang Guan, and Chen Ye. "Design and Development of Refueling Machine Operation Simulation System in Nuclear Power Plant." Applied Mechanics and Materials 373-375 (August 2013): 1703–9. http://dx.doi.org/10.4028/www.scientific.net/amm.373-375.1703.
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In order to improve the effect of refueling training in nuclear power plant, the simulation system of refueling machine was designed and developed, combining the virtual reality technology with a real control console. The 3D virtual refueling environment of nuclear power plant was established by 3D modeling. Signals from touch screen and console are gathered by PLC and transmitted to PC graphics workstation, control the motion of virtual refueling machine, which realize the refueling operation simulation. The operation in failure modes was also realized in the system through the programming of failure database. The results show that the system runs normally and can simulate refueling operation in normal and abnormal modes, the training of refueling personnel is implemented effectively.
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Sallami, Abderrahmene, Dhia Mzoughi, Hatem Allagui, and Abdelkader Mami. "Efficiency of bond graph and external model integration for alarm processing of a central air conditioning system." International Journal of Advances in Applied Sciences 9, no. 4 (December 1, 2020): 313. http://dx.doi.org/10.11591/ijaas.v9.i4.pp313-325.
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<p><span>The design of a supervision system based on the external model by structuring the industrial process according to several modes of operation (degraded and normal). The disadvantage of this model is that it describes the industrial process components as functions regardless of their dynamics without going into detail. Hence the interest of the bond graph model to fill the external model limits. The performance of the proposed supervisory system using both models lies in the detection and location of faults for each mode of operation. The bond graph model enriched by the concept of causality and thanks to these structural properties can clearly display the elements of the physical system taking into account their dynamics in normal and abnormal operation. The results of our research have been applied to central air conditioning system; the development of the proposed project has proceeded from the modeling stage to the reconfiguration stage of the system.</span></p>
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Skoroglyadov, Alexsandr V., U. Haixiao, Chao Zhang, E. Kochiay, and A. V. Germanov. "The progress in study of results of treatment and prevention of comissures of knee joint." Medical Journal of the Russian Federation 22, no. 6 (December 15, 2016): 287–91. http://dx.doi.org/10.18821/0869-2106-2016-22-6-287-291.
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The commissures of knee joint develop after operation or knee trauma at the expense of abnormal proliferation of fibrous tissue provoking limitation of amplitude of motion, arthralgia and joint stiffness. So far, pathogenesis of commissure of knee joint remains unclear. however, there is information that after operation increased secretion of fibroblasts accelerates deposit of extracellular matrix as main mechanism of development of commissures. The application of innovative medical technologies to operate knee joint ameliorated outcomes of treatment and quality of life of patients. However, after surgical operations some patients experience painful sensations and limitation of amplitude of motion of knee joint. The study was targeted to ameliorating of prognosis of operative interventions by means of investigation of pathogenesis of commissure process and possible modes of its prevention.
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Ding, Fei, En Tong, Ai Guo Song, Jian Qing Li, and Guang Ming Song. "Development of a Portable ZigBee-Based Nuclear Radiation Monitoring and Detection System." Applied Mechanics and Materials 130-134 (October 2011): 2639–42. http://dx.doi.org/10.4028/www.scientific.net/amm.130-134.2639.
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This paper presents the development of a novel nuclear radiation monitoring and detection system. With the lightweight and global positioning features, the implemented wireless nuclear detection node can easily be deployed to discover unusual or abnormal radioactivity and map the events. ZigBee-based multi-hop mesh communication is adopted between nuclear detection nodes. All wireless nuclear detection nodes are designed with two working modes, continuous operation and timing operation. The two modes can be switched at any specified time to save energy consumption. Meanwhile, the features of anti-jamming against 802.11 network of ZigBee technology are tested and evaluated.
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Saushev, Alecsandr, and Nikolai Shirokov. "Preventive protection of marine electrical power system from the transition of generating sets to motoring mode." E3S Web of Conferences 244 (2021): 08007. http://dx.doi.org/10.1051/e3sconf/202124408007.
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The approaches that ensure the trouble-free operation of marine power system in abnormal modes were considered. Such modes are usually associated with the system elements failure during operation. Particular attention was paid to the processes occurring in the circuit during transition of one of the generators to the motoring operation mode. The relevance of the considered marine power system issue was substantiated. According to the research results, using time-delay when generating a signal to disable a failed unit operating with reverse power can contribute to defect development in the primary motor. Moreover, time-delay can also lead to zero voltage in the marine electric power system. This circumstance creates the possibility of an emergency that can potentially lead to a shipping accident with the most serious consequences. The problem of timely shutdown of a faulty electrical machine before its transition to the motoring mode is defined in the research, as well as the overload prevention problem for primary motors remaining in working condition. An original diagnostic indicator was proposed based on study, which allows identifying the inoperative state of generator unit during operation. The new approach was developed, which implements the preventive control method for the marine power system in case of element failure. The forecasting of the system operation modes in case of a generator set failure, and its structural adaptation to the occurred malfunction is carried out. In contrast to the existing methods, the practical implementation of the proposed solution will allow accident-free transition of marine power system to a partially operational state without the emergency. This will have a beneficial effect on the safety of ship as a whole.
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Kuz’min, D. A., and A. Yu Kuz’michevskiy. "THE SAFETY FACTORS OF PROBABILITY REACHING LIMITING STATES OF NPP EQUIPMENTS AND PIPELINES DURING DIFFERENT OPERATING MODES." Spravochnik. Inzhenernyi zhurnal, no. 291 (June 2021): 18–23. http://dx.doi.org/10.14489/hb.2021.06.pp.018-023.
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Reliability theory makes it possible to determine the probabilities of destruction, reaching limit states, equipment and pipeline failures (E&P). Normative documents, as a rule, define requirements for integral indicators of reliability or safety of objects, but do not establish requirements for admissible values of probabilities for individual systems and data elements of objects. This article proposes the approach for determining the permissible values of the probabilities of reaching the yield stress or ultimate strength by operating stresses on the basis of design data on loads and data from certificates on the mechanical properties of metal. During operation, the achievement of the working stresses in metal of E&P value of the permissible stress values is a probabilistic event, in this fact, the probabilistic approach has been developed to obtain the safety factor of probability reaching limiting states. The developed approach is based on the methods of strength science, statistical analysis and probability theory. The object of application of the developed approach is thermal mechanical equipment used in different branches of technology. Using the example of the main circulation pipeline of the NPP with WWER-440, the presence of a reserve in the probability of reaching the limit state is shown and a relationship is established between the stress variation coefficient and the calculated probability for normal operation and abnormal operation. This approach determines the reserve for the probability of destruction, which will justify the extension of the resource or optimize the operating parameters of the objects under consideration.
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Shi, Tongyu, Jinghan Lai, Runping Gu, and Zhiqiang Wei. "An Improved Artificial Neural Network Model for Flights Delay Prediction." International Journal of Pattern Recognition and Artificial Intelligence 35, no. 08 (March 24, 2021): 2159027. http://dx.doi.org/10.1142/s0218001421590278.
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With the limitation of air traffic and the rapid increase in the number of flights, flight delay is becoming more frequent. Flight delay leads to financial and time losses for passengers and increases operating costs for airlines. Therefore, the establishment of an accurate prediction model for flight delay becomes vital to build an efficient airline transportation system. The air transportation system has a huge amount of data and complex operation modes, which is suitable for analysis by using machine learning methods. This paper discusses the factors that may affect the flight delay, and presents a new flight delay prediction model. The five warning levels are defined based on flight delay database by using K-means clustering algorithm. After extracting the key factors related to flight operation by the grey relational analysis (GRA) algorithm, an improved machine learning algorithm called GRA — Genetic algorithm (GA) — back propagation neural network, GRA-GA-BP, is introduced, which is optimized by GA. The calculation results show that, compared with models before optimization and other two algorithms in previous papers, the proposed prediction model based on GRA-GA-BP algorithm shows a higher prediction accuracy and more stability. In terms of operation efficiency and memory consumption, it also has good performance. The analysis presented in this paper indicates that this model can provide effective early warnings for flight delay, and can help airlines to intervene in flights with abnormal trend in advance.
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Maestri, Mauricio, Andrés Farall, Pablo Groisman, Miryan Cassanello, and Gabriel Horowitz. "A robust clustering method for detection of abnormal situations in a process with multiple steady-state operation modes." Computers & Chemical Engineering 34, no. 2 (February 2010): 223–31. http://dx.doi.org/10.1016/j.compchemeng.2009.05.012.
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Doletskaya, Larisa I., Vladislav I. Ziryukin, and Roman V. Solopov. "An electric power system object model creating experience for researching the operation of digital means of relay protection and automation." Journal Of Applied Informatics 16, no. 4 (August 31, 2021): 83–95. http://dx.doi.org/10.37791/2687-0649-2021-16-4-83-95.
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The article is devoted to the operation logic modeling of relay protection and automation terminals in order to their verification, adjustment and further exploitation. The problem of adjusting protection terminals mutual interaction is unlikely to appear in real conditions due to wide variety of them. The authors propose a solution to this problem by creating a verified model based on a digital twin of an electric power network section created in the MatLab software package. This model helps to study the functioning of the researched protection settings in nominal, repair, emergency and post-emergency equipment operation modes. A model of the selected substation was created displaying all the properties that are significant for research of the original one. In addition, the requirements analysis for the main and backup protection operation settings of the three-winding transformers was carried out. The main unit is a differential transformer relay protection and the backup one is maximal current protection in amount of three units for every transformer winding circuit: higher, middle and lower transformer voltage branch. The model makes it possible to analyze the relay protection operation selectivity by checking the current settings which could be imported from XML documents unloaded from existing terminals and to evaluate the correctness of new calculated ones with the possibility of their manual input. As a result of the researched object modeling, a three-stage operation analysis of the differential and maximal current protections was carried out. It has shown relay protection selective operation both in the case of nominal and abnormal modes, including the event of the main transformer protection malfunction. This technique can be extended to the other electric power network.
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Chandrasekaran, Kumar, Jasper John Sahayam, Sundarsingh Jebaseelan Somasundaram David Thanasingh, Sripriya Ramalingam, Hady H. Fayek, Nagananthini Ravichandran, and Eugen Rusu. "Performance of Multifunctional Smart PV-Based Domestic Distributed Generator in Dual-Mode Operation." Machines 9, no. 12 (December 15, 2021): 356. http://dx.doi.org/10.3390/machines9120356.
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This article briefs about a smart multifunctional single-phase inverter control for a domestic solar photo voltaic (PV)-based distributed generation that can work in both a grid-connected mode and an islanded mode by making the inverter mimic the operation of a synchronous generator. The control objectives were threefold: to provide the required active and reactive power for normal operating conditions and under varying operating conditions, to maintain the rated voltage and the rated frequency for the islanded mode, and to switch between the two modes of operation with the least amount of disturbance for the system while behaving as a virtual synchronous generator (VSG). The control structure is divided into three major loops: the outermost loop responsible for power control, the middle loop responsible for voltage control, and the innermost loop responsible for current control. The proposed control methodology incorporates the functionalities of the grid-connected and the islanded-mode control into a single complex structure and thus provides support to the grid under abnormal conditions while providing good-quality power to consumers under grid failure. The efficacy of the system is good. The operation under various modes were simulated in MATLAB Simulink, and the proportional integral (PI) controllers used for current controllers were tuned using particle swarm optimization (PSO). It can be concluded that the control structure becoming complex is benefitted by the added advantages of the smart PV system. The smart domestic PV system helps the prosumer to actively provide frequency support and voltage support, adding frequency support to the existing multifunctional PV systems.
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Kechin, Alexander V., Alexander V. Levin, Sergei P. Khaliutin, and Boris V. Zhmurov. "ORGANIZATION OF POWER SUPPLY OF THE FIRST CATEGORY RECEIVERS FOR PERSPECTIVE CIVIL AVIATION AIRCRAFT." Civil Aviation High TECHNOLOGIES 21, no. 6 (December 26, 2018): 54–64. http://dx.doi.org/10.26467/2079-0619-2018-21-6-54-64.
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The article deals with the issue of providing electric power to the first category receivers in the emergency mode of the power supply systems operation of perspective and modernized aircraft. The analysis of the published scientific works performed both in Russia and abroad, and aimed at solving problems of analyzing abnormal operations mode, synthesizing power supply systems and controlling them in order to prevent dangerous consequences is carried out. The authors considered the ingenious technical solutions aimed at providing the necessary quality power supply for the first category receivers in the emergency operation modes of the aircraft power supply systems for the safe completion of flight and landing. The research analysis and generalization of data on the technical characteristics of units and devices developed by the world's leading manufacturers of aviation equipment and used as emergency sources of electrical power on board modern civil aviation aircraft has been completed. The advantages and disadvantages of each technical solution are determined, as well as limitations to the area of their application are formed. The analysis of perspective emergency sources of the electric power including those, which previously were not applied in aviation because of their insufficient technical perfection, for example, hydrogen electrochemical generators is carried out. Based on the performed analysis, a solution which allows improving the operating modes of the electrical batteries is proposed. The offered solution makes it possible to increase the reliability and durability of electrical batteries, as well as the power supply duration of the first category receivers from them.
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Li, Huimin, Li Ji, Feng Li, Hairui Li, Qingguo Sun, Zhihong Li, Hongmei Yan, Wei Guan, Lunyan Wang, and Ying Ma. "Operational Safety Risk Assessment for the Water Channels of the South-to-North Water Diversion Project Based on TODIM-FMEA." Complexity 2020 (December 12, 2020): 1–15. http://dx.doi.org/10.1155/2020/6691764.
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The South-to-North Water Diversion Project consists of long-distance water delivery channels and a complicated geological environment along the way. To deal with the operation safety of the water conveyance channels in the middle route of the South-to-North Water Diversion Project, this study analyzes six failure modes: structural cracks, poor water delivery during ice periods, instability of canal slopes, material aging, abnormal leakage, and foundation defects. Based on FMEA, a multigranularity language evaluation method that can be converted into interval intuitionistic fuzzy numbers is used to evaluate the severity (S), occurrence (O), and detection difficulty (D) of the six failure modes. Interval intuitionistic fuzzy entropy is used to calculate the weights of the risk factors. Finally, a ranking model of each failure mode is built based on the TODIM method. The final ranking results show that the risk of abnormal leakage is the largest, and the risk of poor water delivery during ice periods is the smallest. The feasibility and validity of the calculation results are verified by comparing them with the ranking results of the traditional RPN and TOPSIS methods. The TODIM-FMEA risk assessment model offers a new solution to the problem of risk assessment for water transfer projects.
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Zhang, Tao, Tai Ning Yan, Li Zhen Zhou, and Chuan De An. "Development of Drill Monitor and Operation Mode Recognition Based on All Hydraulic Core Drilling Rig." Advanced Materials Research 383-390 (November 2011): 1819–24. http://dx.doi.org/10.4028/www.scientific.net/amr.383-390.1819.
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For rocks complexity, geologic drilling is a high cost project, and it is high risk. Drill monitor is an important tool in monitoring drilling, scientific analysis and decision. It can continuously monitor drilling process, identify and forecast abnormal operation modes. It is the key means to reduce drilling accidents and ensure high efficiency, high quality and low cost. This paper analyzed some problems of domestic drill monitor based on the research status on drill monitor at home and abroad. Author considered all hydraulic core drilling rig with 2000m drilling capacity as research object, and modularly designed multi-drilling-parameter data acquisition system according to the geologic exploration own characteristics. This system can identify typical drilling operation modes used data handling techniques of wavelet analysis and time series analysis. With implement of state geology investigation strategy, drilling workload increase greatly, drilling depth increase continuously, and the drill monitor has a very wide application prospect.
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Emara, Dina, Mohamed Ezzat, Almoataz Y. Abdelaziz, Karar Mahmoud, Matti Lehtonen, and Mohamed M. F. Darwish. "Novel Control Strategy for Enhancing Microgrid Operation Connected to Photovoltaic Generation and Energy Storage Systems." Electronics 10, no. 11 (May 25, 2021): 1261. http://dx.doi.org/10.3390/electronics10111261.
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Recently, the penetration of energy storage systems and photovoltaics has been significantly expanded worldwide. In this regard, this paper presents the enhanced operation and control of DC microgrid systems, which are based on photovoltaic modules, battery storage systems, and DC load. DC–DC and DC–AC converters are coordinated and controlled to achieve DC voltage stability in the microgrid. To achieve such an ambitious target, the system is widely operated in two different modes: stand-alone and grid-connected modes. The novel control strategy enables maximum power generation from the photovoltaic system across different techniques for operating the microgrid. Six different cases are simulated and analyzed using the MATLAB/Simulink platform while varying irradiance levels and consequently varying photovoltaic generation. The proposed system achieves voltage and power stability at different load demands. It is illustrated that the grid-tied mode of operation regulated by voltage source converter control offers more stability than the islanded mode. In general, the proposed battery converter control introduces a stable operation and regulated DC voltage but with few voltage spikes. The merit of the integrated DC microgrid with batteries is to attain further flexibility and reliability through balancing power demand and generation. The simulation results also show the system can operate properly in normal or abnormal cases, thanks to the proposed control strategy, which can regulate the voltage stability of the DC bus in the microgrid with energy storage systems and photovoltaics.
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Novakov, I., A. Kuryndin, A. Kirkin, and S. Makovskiy. "ACCOUNTING FOR UNCERTAINTY IN THE INITIAL DATA DURING THE CALCULATIONS OF THE EFFECTIVE MULTIPLICATION FACTOR OF THE NUCLEAR RESEARCH REACTOR CORE." PROBLEMS OF ATOMIC SCIENCE AND TECHNOLOGY. SERIES: NUCLEAR AND REACTOR CONSTANTS 2020, no. 2 (June 26, 2020): 22–29. http://dx.doi.org/10.55176/2414-1038-2020-2-22-29.
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Estimation of the error in calculations, that is caused by uncertainties in the initial data is an integral part of the nuclear facilities safety case. Nuclear safety is one of the fundamental directions in safety case. Incorrect accounting for the uncertainties in the initial data can lead to a row of negative consequences, in particular, incorrect determination of the reactivity margin in various modes of normal operation, as well as in cases of the abnormal operation of nuclear facilities. This article presents results of a research of uncertainties influence on an effective multiplication factor of research reactor PIK. The design basis accident (deliquation of the central experimental channel) was analyzed during the discussed research.
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Bakht, Muhammad Paend, Zainal Salam, Abdul Rauf Bhatti, Waqas Anjum, Saifulnizam A. Khalid, and Nuzhat Khan. "Stateflow-Based Energy Management Strategy for Hybrid Energy System to Mitigate Load Shedding." Applied Sciences 11, no. 10 (May 18, 2021): 4601. http://dx.doi.org/10.3390/app11104601.
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This study investigates the potential application of Stateflow (SF) to design an energy management strategy (EMS) for a renewable-based hybrid energy system (HES). The SF is an extended finite state machine; it provides a platform to design, model, and execute complex event-driven systems using an interactive graphical environment. The HES comprises photovoltaics (PV), energy storage units (ESU) and a diesel generator (Gen), integrated with the power grid that experiences a regular load shedding condition (scheduled power outages). The EMS optimizes the energy production and utilization during both modes of HES operation, i.e., grid-connected mode and the islanded mode. For islanded operation mode, a resilient power delivery is ensured when the system is subjected to intermittent renewable supply and grid vulnerability. The contributions of this paper are twofold: first is to propose an integrated framework of HES to address the problem of load shedding, and second is to design and implement a resilient EMS in the SF environment. The validation of the proposed EMS demonstrates its feasibility to serve the load for various operating scenarios. The latter include operations under seasonal variation, abnormal weather conditions, and different load shedding patterns. The simulation results reveal that the proposed EMS not only ensures uninterrupted power supply during load shedding but also reduces grid burden by maximizing the use of PV energy. In addition, the SF-based adopted methodology is envisaged to be a useful alternative to the popular design method using the conventional software tools, particularly for event-driven systems.
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Zhu, Zi Xin, Jun Zhong Zheng, and Dong Chen. "Using Lubricating Oil Filter Debris Analysis to Monitor Abnormal Wear of Aero-Engine." Applied Mechanics and Materials 86 (August 2011): 821–24. http://dx.doi.org/10.4028/www.scientific.net/amm.86.821.
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With the installation of finer oil filters in the lubrication system of aero-engine, the traditional wear analysis techniques such as Rotating Disc Electrode Atomic Emission Spectrometry Analysis (RDE-AES) become less efficient at detecting abnormal wear failure caused by large debris. These filters capture large debris containing large amounts of tribological information about the operation of an aero-engine. Removal and analysis of the filter debris has proved to be an effective tool for aero-engine health management by determining wear modes and observing failure progression providing long lead times for maintenance. An automated aero-engine oil filter debris analysis system was recently developed. This instrument could efficiently complete filter core washing, debris amount and size distribution analysis, and prepare a patch of the debris for further composition analysis.
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Bashirov, M. G., Z. Kh Pavlova, and A. M. Khafizov. "DEVELOPMENT OF A VIRTUAL SIMULATOR FOR PRACTICING SKILLS IN THE PERSONNEL ACTIONS IN ABNORMAL AND EMERGENCY MODES OF TUBE FURNACES OPERATION." Oil and Gas Business, no. 4 (September 2018): 161. http://dx.doi.org/10.17122/ogbus-2018-4-161-181.
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Tarayevskiy, O. "STUDY OF THE INFLUENCE OF COMPLEX MINING AND GEOLOGICAL CONDITIONS ON OPERATION TRANSIT PIPELINES." Municipal economy of cities 3, no. 156 (July 1, 2020): 105–10. http://dx.doi.org/10.33042/2522-1809-2020-3-156-105-110.
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On the basis of the system approach and analysis of the conditions of operation of transit main gas pipelines, analytical studies of the stresses occurring on the internal surface of the gas pipeline under the conditions of the obverse and reverse operation modes have been carried out. The method of determination (prognostication) of durability of long exploited pipelines, operated in complex mining and geological conditions was proposed. It was shown that during such exploitation of gas pipelines non-project modes are being found that require a detailed analysis of the use of their production capacities, and as a result it has been established that the study section in such conditions. The technique for determining the permissible level of arbitrarily oriented stresses acting on the investigated section of a gas pipeline with a complex technological structure and laid on a section with a disturbed equilibrium of the Earth is developed. It has been proved that the cyclic operation of pipelines and their structural elements in difficult geological conditions leads to an abnormally high background tension, which leads to a decrease in their predicted lifetime. It is proposed to carry out operational control of the stressed-deformed state of pipeline sections laid in complex mining and geological conditions and which have complex technological features. The principle of optimization of gas transportation by pipelines, passing in one technological corridor on the criterion of minimum negative impact on the environment was improved. The technique of determining the potential impact radius, which simultaneously takes into account the mode of operation of the gas pipeline, its actual technical condition, as well as the parameters of abnormal areas with disturbed equilibrium of the earth, was proposed. The developed method allows determining the necessary security zone on each individual site, in particular, to substantially reduce or increase it in relation to existing real conditions. In order to design new gas pipelines, there will be no pipelines in the same technological corridor, and for existing pipelines operated in the same technological corridor, it will be possible to reduce the impact of the emergency situation or even make it impossible because of optimal loading of the gas pipelines. The expediency of carrying out such experiments and the results obtained will allow to prevent accidents and failures of gas pipelines that lies in complex mining and geological conditions, to ensure their reliability during long service life as well. Keywords: gas, underemployment, stressful situation, density, mathematical model.
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Liang, Jiaqi, Yibei Wu, Jun’e Li, Xiong Chen, Heqin Tong, and Ming Ni. "Security Risk Analysis of Active Distribution Networks with Large-Scale Controllable Loads under Malicious Attacks." Complexity 2021 (February 19, 2021): 1–12. http://dx.doi.org/10.1155/2021/6659879.
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With the development of distributed networks, the remote controllability of the distributed energy objects and the vulnerability of user-side information security protection measures make distributed energy objects extremely vulnerable to malicious control by attackers. Hence, the large-scale loads may produce abnormal operation performance, such as load casting/dropping synchronously or frequent and synchronous casting and dropping, and hence, it can threaten the security and stable operation of the distribution networks. First, we analyze the security threats faced by industrial controllable load, civil controllable load, and the gains and losses of attacks on the distribution networks. Considering the factors of cyber attacks, we propose a control model and cyber attack model in active distribution networks (ADNs). And, three types of attacks that the target suffered are defined on the basis of “on” and “off” modes for control. Then, the controllable load was maliciously controlled as the research object, and a suitable scenario is selected. The impact of malicious control of the controllable load on the power supply reliability and power quality of the distribution networks are simulated and analyzed, and risk consequences for different types of attacks are provided.
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Belyamna, Mohammed Amine, Abdelmoumene Guedri, and Racim Boutelidja. "Reliability Analysis of a Pre-Cracked Structure in Accidental Operation Conditions." Key Engineering Materials 820 (September 2019): 188–202. http://dx.doi.org/10.4028/www.scientific.net/kem.820.188.
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Evaluating the integrity of a structure consists in proving its ability to realize its mechanical functions for all modes of loading, normal or accidental, and throughout its lifetime. In the context of nuclear safety, the most important structures consider the presence of a degradation grouping several aspects, such as cracks. In this context, the fracture mechanics provide the tools needed to analyze cracked components. Its purpose is to establish break criteria for judging loading margins in normal or accidental operating conditions. The seismic load is one of the dominant loads for the failure assessment of the pipes. Its probabilistic dispersion, however, was not taken into account in the past probabilistic fracture mechanics analysis. The objective of this paper is to simulate and analyze the effect of abnormal stress on the reliability of tow pipe sizes. As result the seismic stress has more effect on the break probability, but not for the leak probability. In the case without a seismic load, the break probability is mainly dominated by an initial crack size. The earthquake has much effect on the break probability for the large diameter pipe, not for the small diameter pipe. In the large diameter pipe, the break probability increases gradually with the time. The leak probability of both pipe sizes is not affected by the seismic curve.
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Iranzi, Joseph, Hanam Son, Youngsoo Lee, and Jihoon Wang. "A Nodal Analysis Based Monitoring of an Electric Submersible Pump Operation in Multiphase Flow." Applied Sciences 12, no. 6 (March 9, 2022): 2825. http://dx.doi.org/10.3390/app12062825.
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Electrical submersible pump (ESP) operation is compromised by free gas, resulting in premature pump failure and production losses in new wells. It is essential to detect the onset of abnormal operations. We develop a model that predicts abnormal ESP operation when the free gas level increases in the pump. The model compares operation parameters with the parameters of normal operating ranges; it shuts down the ESP when necessary. We used a Schlumberger PIPESIM software (version 2017.01) to perform nodal analysis technique; we tested the model using the other multiphase correlation model and field case studies (where the gas problem in ESP was reported). We employ a homogenous model to calculate the differential pump pressures at various gas volume fractions. Nodal analysis of the intake and discharge point predicted the commencement of abnormal ESP conditions and the associated parameters (critical gas fraction, minimum operating pump intake pressure, and pump discharge pressure). The model results were similar to other surging correlation models (e.g., Romero, Dunbar, Turpin, Cirilo, and Zhou models); they were also identical to field case studies. We identify three performance stability phases when an ESP is exposed to free gas. These are the normal and abnormal operating ranges, as well as the ESP shutdown condition. Modeling permits careful monitoring of ESP operations that can be compromised by free gas.
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Grabovskii, Vladimir. "Torsional Vibrations of the Steam Turbine Shaft Line and Estimation of the Residual Life of Its Elements." Известия высших учебных заведений. Электромеханика 63, no. 6 (2020): 91–98. http://dx.doi.org/10.17213/0136-3360-2020-5-91-98.
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A comparative quantitative assessment of the damage and residual life of the shaft line elements for differ-ent types of high-power steam turbines at the end of their design life is made by mathematical modeling. The analysis covers all elements of the shaft line: from the steam turbine Central pump to the turbine generator ex-citer. The simulated circuit includes turbo generators, transformers, gate converters, AC and DC power lines. When modeling, an approach is used from the position of proper coordinates, which provides maximum meth-odological consistency of the models of the listed devices and allows you to directly reproduce electromagnetic and mechanical transients with the determination of instantaneous values of currents, voltages, electromagnet-ic and torsional moments. To estimate damage, we used the deformation criterion for soft and hard loads in the zone of low-cycle and force criterion in the zone of multi-cycle fatigue. The influence of the number of starts and running time of a steam turbine on the damage and residual life of its shaft elements is studied. When de-termining the remaining life, in addition to starts, other abnormal operating modes of the turbo generator were taken into account during the turbine operating time: short circuits and their disconnections, unsuccessful high-speed automatic re-activation, subsynchronous resonance due to both the operation of the control system of the PPT and the automatic generator excitation regulator. The influence of attenuation of electromagnetic transients in the generator and damping of torsional vibrations on the degree of reduction of the residual life of the shaft elements is analyzed. The results obtained can be used for a comprehensive solution of the issue of further operation of steam turbines that have spent their design life.
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Belousova, Maria, Roman Aleshko, Rafina Zakieva, Malvina Karabasheva, Sergey Gorovoy, and Sultanbek Kozhemov. "Development of equipment management system with monitoring of working characteristics of technological processes." Journal of Applied Engineering Science 19, no. 1 (2021): 186–92. http://dx.doi.org/10.5937/jaes0-28855.
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The work provides multi-purpose optimization of the baklava production process based on technology of agent systems, the intelligent environment of process control systems. The general architecture of the control system intelligent environment with agent technologies for recognizing abnormal situations was developed and adaptive baklava production regulators were synthesized. It allows you to get the specified dynamic characteristics of the control object based on the developed adaptive systems for adjusting the PID controllers, controlling the parameters of the dough, kneading, separation and baking of baklava. The proposed approach to the construction of an automated process control system with an intelligent environment will reduce the variance of fluctuations in energy consumption, increase the production rate of high-quality baklava and reduce the time for re-equipment and technological modes of operation of baklava production lines.
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Pacheco, João, Gustavo Oliveira, Filipe Magalhães, Carlos Moutinho, and Álvaro Cunha. "Vibration-Based Monitoring of Wind Turbines: Influence of Layout and Noise of Sensors." Energies 14, no. 2 (January 15, 2021): 441. http://dx.doi.org/10.3390/en14020441.
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The reduction in operating and maintenance costs of wind farms is a fundamental element to guarantee the competitiveness and growth of the wind market. Wind turbines are highly dynamic structures prone to wear during their lifetime. Therefore, dynamic monitoring systems represent an excellent option to continuously evaluate their structural conditions. These systems allow early detection of damages, permit a proactive response, minimising downtime, and maximising productivity. In this context, the present paper describes the main results obtained with alternative instrumentation strategies tested in a 2.0 MW onshore wind turbine to reduce the costs of the monitoring equipment and at the same time ensure an adequate accuracy in structural condition evaluation. The data processing strategy encompasses the use of operational modal analysis combined with algorithms that deal with the particularities of operation of the wind turbines to continuously track the main vibration modes. After this automated online identification, the influence of the environmental and operating conditions on the tracked natural frequencies is mitigated, making the detection of abnormal variations of the natural frequencies possible, which might flag the appearance of damage. A database of continuously collected acceleration time series during one year is adopted to test the efficiency of alternative monitoring system layouts in detecting simulated damage scenarios. The tested alternative monitoring layouts present a varying number of sensors, alternative distributions in the wind turbine tower, and different sensor noise levels.
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Kostomakhin, M. N., N. A. Petrishchev, and A. S. Sayapin. "A System for the Remote Monitoring of Vehicle Technical Condition: Kirovets Tractor Gearbox Case Study." Agricultural Machinery and Technologies 15, no. 3 (October 6, 2021): 22–27. http://dx.doi.org/10.22314/2073-7599-2021-15-3-22-27.
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Abstract. The authors noted that in order to increase the energy-saturated equipment technical readiness, reduce its operation costs and ensure full use of the resource, it is necessary to quickly assess the current technical condition. The authors have created a counter-indicator prototype for high-precision control of gearbox technical condition. (Research purpose) To formulate a proposal for developing a system for the remote monitoring of gearbox technical condition applicable to the Kirovets tractor family. (Materials and methods) To increase the precision level of traceability and technical condition detection, a system of diagnostic tools was proposed based on the developed counters-indicators, which take into account design features when determining diagnostic parameters. (Results and discussion) It was shown that to assess the gearbox technical condition, it is necessary to use additional monitoring systems, obtain information for calculating the residual life, when using direct measurements and having a possibility of the ongoing monitoring over the actual change in the gearbox units diagnostic parameters. The authors studied the options for using meter-indicators to minimize group II and III failures during operation.(Conclusions) It was identified that in order to increase the level of gearbox operational reliability, it is necessary to introduce a system of counters-indicators. The authors revealed the possibility of monitoring the individual unit technical condition in accordance with the specified indicators, as well as in order to prevent operation in emergency (abnormal) modes.
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Li, Xuan, Jianyong Zheng, Fei Mei, Haoyuan Sha, and Danqi Li. "An Early Warning Method of TCU Failure in Electromagnetic Environment Based on Pattern Matching and Support Vector Regression." Energies 13, no. 21 (October 22, 2020): 5537. http://dx.doi.org/10.3390/en13215537.
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With the continuous improvement of the voltage level of the power system, the electromagnetic interference problem of the converter station has become more and more serious. The thyristor control unit (TCU) is the core equipment of the converter valve, and its normal operation is related to the safe and stable operation of the entire converter valve. This paper starts with the actual electromagnetic environment in the converter valve hall, analyzes the failure principle of the TCU under electromagnetic disturbance, and observes the electromagnetic field distribution and sensitive components on the circuit board. Then, a TCU failure early warning method based on pattern matching and support vector regression (SVR) is proposed. The failure trend is deduced by constructing an abnormal information vector, and then the failure predictor is constructed using support vector regression optimized by grid search (GS), genetic algorithm (GA), and particle swarm optimization (PSO). Considering the failure type and warning time comprehensively, an early warning is issued when the failure mode probability increases to the threshold. When new failure modes appear, the failure mode library will continue to expand. The calculation example shows that this method can effectively warn the TCU failure in the electromagnetic environment, and its prediction accuracy can reach 89.2%, which is better than the traditional failure prediction method.
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Wang, Zhi Chen, Ying Song, and Ying Ming Shen. "A New Monitoring Method of Wheel/Rail Contact Forces Caused by Out-of-Round Railway Wheels." Applied Mechanics and Materials 178-181 (May 2012): 1125–30. http://dx.doi.org/10.4028/www.scientific.net/amm.178-181.1125.
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Traditional methods of wheel-rail contact forces measurement all need strain gauges on wheel sets or rails. The shortcomings of strain gauges such as zero-drift, poor anti-interference property and instability of test system can’t meat wheel/rail force test requirements in high-speed railways. A method based on PVDF piezoelectric sensing technology is presented for the test of wheel/rail contact force. Firstly, on the basis of the theory of vehicle-track coupling dynamics and by means of simulation software ADAMS/Rail, a three-dimensional train-track simulation model is established. Secondly, the modes and characteristics of wheel/rail impact vibrations due to non-roundness of railway wheels are investigated in high-speed railway operation. The relationship between the range for acceptable roundness values and vehicle speed is determined. Finally, the view that it is of important significance to establish wheel/rail force real-time monitoring system is expanded, so that abnormal conditions caused by out-of-round wheels can be detected in time, to ensure high-speed railway traffic safety. The study is very important for enhancing the stability and economy signification of rail transmission.
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Kalabin, D. A., A. Yu Lipovka, and Yu L. Lipovka. "Computer simulation and full-scale measurements of the load flow in a functioning heating network." Proceedings of Irkutsk State Technical University 25, no. 1 (March 20, 2021): 44–56. http://dx.doi.org/10.21285/1814-3520-2021-1-44-56.
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The article aims to identify patterns in the distribution of heating energy to consumers with a varying availability of regulation equipment under real conditions of a central heating network, as well as to compare the results of computer simulation with full-scale measurements. For computer simulation, well-known mathematical methods for calculating the load flow in hydraulic circuits were used. Experimental studies of the operation modes of heat supply systems were carried out using the data of the control and monitoring systems of thermal power plants using the Siemens Simatic PCS7 software, a Portaflow 300 ultrasonic flow meter, stationary electromagnetic flow transducers, verified and certified manometers and thermometers. The graphs of the actual hydrodynamic modes of the heating network under study were obtained at outdoor air temperatures from +8 to -37°C, as well as under abnormal conditions (temperature drop in the supply pipeline and pressure drop at the heating network input). It was proposed to use jointly the simulation by means of the JA_Net software and full-scale measurements of the thermohydraulic operating modes of a centralised heat supply system, whose consumers have a various degree of regulation equipment. It was shown that the proposed complex method of qualitative and quantitative assessment of the efficiency of district heating networks makes it possible to identify the features of control of their hydraulic modes when connecting new consumers with a varying degree of automation. According to the obtained characteristics of changes in the flow rate of the coolant in the consumers’ internal systems depending on the pressure drop at the tie-in point, the lack of response to emergency situations on part of the consumers whose heat supply systems are equipped with the means of qualitative and quantitative regulation of the heat load, is associated with the process of automatic adjustment of the degree of opening of flow controllers and control valves at individual points. In future work, we will develop guidelines for levelling the imbalance of the heating network under the conditions of uneven provision of facilities with automation equipment when implementing projects for the complex modernisation of heat consumers or connecting new facilities to existing heat supply networks.
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Murakami, Y., and S. S. Houston. "Dynamic inflow modelling for autorotating rotors." Aeronautical Journal 112, no. 1127 (January 2008): 47–53. http://dx.doi.org/10.1017/s0001924000001986.
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Abstract The dynamic inflow model is a powerful tool for predicting the induced velocity distribution over a rotor disc. On account of its closed form and simplicity, the model is especially practical for studying flight mechanics or for designing control systems for helicopters. Scant attention has, however, been paid so far in utilising the dynamic inflow model to analyse an autorotating rotor, which is different from a powered rotor in the geometric relation between the direction of the inflow and the rotor disc. Autorotation is an abnormal condition for helicopters, but for gyroplanes it is the normal mode of operation. Therefore the theoretical discussion on an autorotating rotor is of importance not only to improve the understanding of present gyroplanes, but also in the development of new gyroplanes and to analyse the windmill-brake state of helicopters. Dynamic inflow modelling is reviewed from first principles, and this identifies a modification to the mass flow parameter. A qualitative assessment of this change indicates that it is likely to have a negligible impact on the trim state of rotorcraft in autorotation, but a significant effect on the dynamic inflow modes in certain flight conditions. This is confirmed by numerical simulation, although considerable differences only become apparent for steep descents with low forward speed. It is concluded that while modification of the mass flow parameter is perhaps mathematically accurate, for practical purposes it is required only in a limited area of the flight envelope of autorotating rotorcraft.
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Han, Junwei, Xudong Han, Qingfei Kong, and Liang Cheng. "psSubpathway: a software package for flexible identification of phenotype-specific subpathways in cancer progression." Bioinformatics 36, no. 7 (December 10, 2019): 2303–5. http://dx.doi.org/10.1093/bioinformatics/btz894.
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Abstract Summary Subpathways, which are defined as local gene subregions within a biological pathway, have been reported to be associated with the occurrence and development of cancer. The recent subpathway identification tools generally identify differentially expressed subpathways between normal and cancer samples. psSubpathway is a novel systems biology R-based software package that enables flexible identification of phenotype-specific subpathways in a cancer dataset with multiple categories (such as multiple subtypes and developmental stages of cancer). The operation modes include extraction of subpathways from pathway networks, inference with subpathway activities in the context of gene expression data, identification of subtype-specific subpathways, identification of dynamic-changed subpathways associated with the cancer developmental stage and visualization of subpathway activities of samples in different phenotypes. Its capabilities enable psSubpathway to find specific abnormal subpathways in the datasets with multi-phenotype categories and to fill the gaps in the recent tools. psSubpathway may identify more specific biomarkers to facilitate the development of tailored treatment for patients with cancer. Availability and implementation The package is implemented in R and available under GPL-2 license from the CRAN website (https://cran.r-project.org/web/packages/psSubpathway/). Supplementary information Supplementary data are available at Bioinformatics online.
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Lin, Rongheng, Zezhou Ye, and Yingying Zhao. "OPEC: Daily Load Data Analysis Based on Optimized Evolutionary Clustering." Energies 12, no. 14 (July 11, 2019): 2668. http://dx.doi.org/10.3390/en12142668.
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Customers’ electricity consumption behavior can be studied from daily load data. Studying the daily load data for user behavior pattern analysis is an emerging research area in smart grid. Traditionally, the daily load data can be clustered into different clusters, to reveal the different categories of consumption. However, as user’s electricity consumption behavior changes over time, classical clustering algorithms are not suitable for tracing the changes, as they rebuild the clusters when clustering at any timestamp but never consider the relationship with the clusters in the previous state. To understand the changes of consumption behavior, we proposed an optimized evolutionary clustering (OPEC) algorithm, which optimized the existing evolutionary clustering algorithm by joining the Proper Restart (PR) Framework. OPEC relied on the basic fact that user’s energy consumption behavior would not abruptly change significantly, so the clusters would change progressively and remain similar in adjacent periods, except for an emergency. The newly added PR framework can deal with a situation where data changes dramatically in a short period of time, and where the former frameworks of evolutionary clustering do not work well. We evaluated the OPEC based on daily load data from Shanghai, China and the power load diagram data from UCI machine learning repository. We also carefully discussed the adjustment of the parameter in the optimized algorithm and gave an optimal value for reference. OPEC can be implemented to adapt to this situation and improve clustering quality. By understanding the changes of the users’ power consumption modes, we can detect abnormal power consumption behaviors, and also analyze the changing trend to improve the operations of the power system. This is significant for the regulation of peak load in the power grid. In addition, it can bring certain economic benefits to the operation of the power grid.
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Yang, Chaoyi, Ye Liu, Jianyi Xiao, Xiaobo Huang, and Jiahua Chen. "Research on Intelligent Operation and Maintenance Model of Large Database for Electric Power Industry." Journal of Physics: Conference Series 2095, no. 1 (November 1, 2021): 012028. http://dx.doi.org/10.1088/1742-6596/2095/1/012028.
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Abstract Existing research on automated database operation and maintenance for the electrical industry mainly focuses on distributed and cloud platforms, and there is a lack of traditional large-scale database intelligent operation and maintenance research. This paper designs an overall operation and maintenance model framework of “intelligent perception-intelligent decision-intelligent execution”, and proposes feasible implementation plans, including: (1) Use the prophet time series forecasting model to perceive and predict important database performance indicators, and dynamically adjust the threshold of each performance indicator according to the predicted value; (2) Perform correlation analysis on abnormal indicators through the association rule model to construct “Indicators”->Operation” optimized combination operation strategy library for intelligent decision making; (3) According to the intelligent decision library, automatically restrict the associated operations under abnormal conditions to ensure the normal operation of the service and realize intelligent execution.
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Saushev, A., N. Shirokov, and A. Butsanets. "Rapid identification of the technical condition of a marine electric power system." Journal of Physics: Conference Series 2061, no. 1 (October 1, 2021): 012032. http://dx.doi.org/10.1088/1742-6596/2061/1/012032.
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Abstract The article is devoted to the development of approaches to the rapid identification of the technical condition of marine electric power systems. It is shown that the means of technical diagnostics used on modern ships are used only for maintenance and repair of power equipment and are not adapted to provide preventive control in abnormal operating modes. The definition of rapid identification of a technical state as a process of technical diagnostics of a marine electric power system for the purposes of preventive and emergency control of its technical condition is given. The statement is substantiated that the means of technical diagnostics should not only identify the inoperative state of the system elements, but also predict the mode of its operation after disconnecting the inoperative generator set, provide the information necessary to ensure a trouble-free transition of the electric power system to a partially operable state. It is shown that, in contrast to the existing approaches to diagnosing the technical state of the ship’s electric power system, it is necessary to take into account the rate of change of the controlled parameter, as well as to determine the probable time of its reaching the maximum permissible value. The necessity of identifying an inoperative element of the system and the implementation of control actions to exclude an emergency until the moment of overloading of the operable generating sets, their shutdown by protection and power outage is substantiated. This information in each specific case will allow the decision-making system of the marine electric power system to formulate recommendations for the maintenance personnel and the preventive protection system on the necessary impacts on the control object in order to avoid an emergency. The main reasons for overloading the marine electric power system have been formulated, algorithms have been developed for the practical solution of the problem of rapid identification of the technical state of the system for cases associated with overloading of serviceable electrical machines due to disconnection of inoperative generator sets.
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Yang, Jing, Lihua Gong, Kunpeng Liu, and Letian Xiu. "Operation Anomaly Monitoring of Customer Service Data Analysis Platform Based on Improved FP-Growth Algorithm." Journal of Physics: Conference Series 2209, no. 1 (February 1, 2022): 012030. http://dx.doi.org/10.1088/1742-6596/2209/1/012030.
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Abstract Aiming at the problems of long time-consuming monitoring and poor monitoring accuracy in traditional customer service data analysis platform operation abnormality monitoring methods, a customer service data analysis platform operation abnormality monitoring method based on the improved FP-Growth algorithm is designed. Obtain customer service data sets, classify data types, filter customer behavior, identify the operating status of the data analysis platform, improve the FP-Growth algorithm to build a rule configuration model, set the platform safety factor threshold, and keep the reconstruction error of customer service data to a minimum Within the scope, optimize the abnormal monitoring mode. The experimental results show that the average recovery time of the proposed customer service data analysis platform operation anomaly monitoring method is 5.239s, and the average platform operation anomaly accuracy rate is 97.3%, indicating that the customer service data analysis platform integrated with the improved FP-Growth algorithm operates abnormally The monitoring method performs better.
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Sheryazov, Saken Koyshybaevich, Sultanbek Sansyzbaevich Issenov, Ruslan Maratbekovich Iskakov, and Argyn Bauyrzhanuly Kaidar. "Special Aspects of Using the Wind Power Plants In the Power Supply System." E3S Web of Conferences 288 (2021): 01003. http://dx.doi.org/10.1051/e3sconf/202128801003.
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The paper describes special aspects of using the wind power plants (wind turbines) in the power grid. The paper provides the classification and schematic presentation of AC wind turbines, analyzes the role, place and performance of wind power plants in Smart Grid systems with a large share of renewable energy sources. The authors also reviews a detailed analysis of existing AC wind turbines in this paper. Recommendations are given for how to enhance the wind power plants in smart grids in terms of reliability, and introduce the hardware used in the generation, conversion and interface systems into the existing power grid. After the wind power plants had been put online, the relevance of the Smart Grid concept for existing power grids was obvious. The execution of such projects is assumed to be financially costly, requires careful study, and development of flexible algorithms, but in some cases this may be the only approach. The analysis of using wind turbines shows that the structural configuration of wind power plants can be based on the principles known in the power engineering. The approaches may differ, not fundamentally, but in engineering considerations. it is necessary to point out that the method of controlling dual-power machines is quite comprehensive so that their wide use will face operational problems caused by the lack of highly professional specialists in electric drives. Therefore, it seems advisable to use square-cage asynchronous generators in wide applications. The paper shows that as the renewable energy sources are largely used in power grids, there is an issue of maintaining the power generation at a required level considering the variability of incoming wind energy. This results in the malfunctions in the operation of relay protection devices and emergency control automatics (RP and ECA), and the complicated control. Also, the standards of the CIS countries and regulatory documents miss the requirements for the wind turbine protections, taking into account their specialty causing the inefficient standard protective logic, which does not work correctly in a number of abnormal and emergency operating modes, and especially Smart Grid in power grids.
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Rumiantsev, Yu V., and F. A. Romaniuk. "An Artificial Neural Network Developed in MATLAB-Simulink for Reconstruction a Distorted Secondary Current Waveform. Part 1." ENERGETIKA. Proceedings of CIS higher education institutions and power engineering associations 64, no. 6 (December 6, 2021): 479–91. http://dx.doi.org/10.21122/1029-7448-2021-64-6-479-491.
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Recently, there has been an increased interest in the use of artificial neural networks in various branches of the electric power industry including relay protection. Аrtificial neural networks are one of the fastest growing areas in artificial intelligence technology. Recently, there has been an increased interest in the use of аrtificial neural networks in the electric power engineering, including relay protection. Existing microprocessor-based relay protection devices use a traditional digital signal processing of the monitored signals which is reduced to a multiplying the values of successive samples of the monitored current and voltage signals by predetermined coefficients in order to calculate their RMS values. In this case, the calculated RMS values often do not reflect the real processes occurring in the protected electrical equipment due to, for example, current transformer saturation because of the DC component presence in the fault current. When the current transformer is saturated, its secondary current waveform has a characteristic non-periodic distorted form, which is significantly differs from its primary (true) waveform, which causes underestimation of the calculated RMS value of the secondary current compared to its true value. In its turn, this causes to a trip time delay or even to a relay protection devices operation failure. The use of аrtificial neural networks in conjunction with a traditional digital signal processing provides a different approach to the functioning of both the measuring and logical parts of the microprocessor-based relay protection devices, which significantly increases the speed and reliability of such relay protection devices in comparison with their traditional implementation. A possible application of the аrtificial neural networks for the relay protection purposes is the fault occurrence detection and its type identification, current transformer secondary current waveform distortion restoration due to its saturation up to its true value, detection the distorted and undistorted sections of the current transformer secondary current waveform during its saturation, primary power equipment abnormal operating modes detection, for example, power transformer magnetizing current inrush. The article describes in detail the stages of the practical implementation of the аrtificial neural networks in the MATLAB-Simulink environment by the example of its use to restore the distorted current transformer secondary current waveform due to saturation.
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Li, Han. "Unconditional Accounting Conservatism and Real Earnings Management." International Journal of Financial Research 9, no. 2 (February 5, 2018): 203. http://dx.doi.org/10.5430/ijfr.v9n2p203.
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This research examines the relationship between unconditional accounting conservatism and real earnings management in China’s corporations. Using the regression models, the real earnings management proxies are found by the abnormal cash flow of operations, the abnormal operation costs and the abnormal discretionary expenses and the aggregated measures. The research sheds light on the negative relationship between unconditional accounting conservatism and real earnings management after controlling internal control quality and audit risk. The results of these inferences remain the same after dealing with the robustness analysis and the endogeneity concerns.
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Hamaguchi, Takashi, Yoshihiro Hashimoto, Toshiaki Itoh, Akihiko Yoneya, and Yoshitaka Togari. "Selection of Operating Modes in Abnormal Plant Situations." JOURNAL OF CHEMICAL ENGINEERING OF JAPAN 35, no. 12 (2002): 1282–89. http://dx.doi.org/10.1252/jcej.35.1282.
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Udiyani, Pande Made, and Muhammad Budi Setiawan. "SOURCE TERM ASSESSMENT FOR 100 MWE PRESSURIZED WATER REACTOR." JURNAL TEKNOLOGI REAKTOR NUKLIR TRI DASA MEGA 22, no. 2 (June 2, 2020): 61. http://dx.doi.org/10.17146/tdm.2020.22.2.5844.
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One of the barriers on the implementation of nuclear energy in Indonesia is public perception towards the safety of nuclear power plants (NPPs). Therefore, it is necessary to perform a study about the radiation impact of normal and abnormal operations of an NPP. In accordance to the program of Ministry of Research and Technology period 2020-2024, concerning the plan to build a small modular reactor (SMR)-type NPP, a radiation safety study has been performed for the 100 MWe Pressurized Water Reactor (PWR-100MWe). Source term release of radioactive substances into the environment from PWR-100MWe is a starting point in the study of the radiological consequences of reactor operation. Therefore, this paper will examine the PWR-100MWe source term under normal and abnormal operating conditions, according to the design and the design basis accident (DBA). The initial trigger of the DBA is Lost of Coolant Accident (LOCA) such as Small LOCA and Large LOCA. Due to the limitations of available SMR data, the study of PWR-100MWe source term refers to the assumption of the release fraction of fission products per subsystem in a larger 1000MWe PWR. It is expected from this assumption that pessimistic source term will be obtained. The study begins with calculation of PWR-100MWe core inventory using ORIGEN2 code based on PWR-100MWe reactor parameters. Through the mechanistic source term model and PWR-1000MWe release parameters, source terms will be obtained for normal operation and abnormal conditions i.e. DBA. Normal source term is used to calculate the consequences of normal operation, which will be used for environmental monitoring and environmental safety analysis of the site. Whereas accident source term is the basis for calculating the radiological consequences of accidents used for SAR documents and nuclear preparedness.Keywords: SMR, PWR-100MWe, normal operation, source term, accident
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Mentes, Alexandros, Panagiota Galiatsatou, Dimitrios Spyrou, Achilleas Samaras, and Panagiota Stournara. "Hydraulic Simulation and Analysis of an Urban Center’s Aqueducts Using Emergency Scenarios for Network Operation: The Case of Thessaloniki City in Greece." Water 12, no. 6 (June 6, 2020): 1627. http://dx.doi.org/10.3390/w12061627.
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The present work aims at developing a hydraulic simulation model for the aqueducts of Thessaloniki city in Greece to model the current operating state of the network, as well as its response to emergency conditions resulting from failure in one of them. Hydraulic simulations performed using WaterGEMS software in an extended period simulation (EPS) mode entail estimating water demand in all areas of the conurbation and calibrating the model under both normal and abnormal conditions. Calibration parameters set include the pipes’ roughness coefficients and head loss characteristics of throttle control valves (TCVs). Failure in the city’s aqueducts is confronted with the development and hydraulic simulation of five emergency scenarios of network operation, two of which consider possible interconnections of the studied aqueducts. These scenarios, which include appropriately defined intermittent water supply schedules for the aqueducts, are created on the basis of fair and equitable management of water among the different areas of the city, also assuming a small number of interventions/operations during the crisis. The simulations performed reveal quite a satisfactory compliance of the system’s operation with the defined schedules, and an improved management of limited water reserves in some areas of the network when considering interconnections of the city’s aqueducts.
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Sun, Xin Ming, and Jia Ji Zhang. "Manufacturing Research on the Ability of Finance Statement Information in Predicting Abnormal Return of Investing Chinese Manufacturing Companies." Advanced Materials Research 1056 (October 2014): 114–17. http://dx.doi.org/10.4028/www.scientific.net/amr.1056.114.
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In 1934, Grahamd and Dodd gave a precise formulation between investor and speculator , as follow: “ a investment operation is one which ,upon thorough analysis promises safety of principle and an adequate return. Operations, not meeting these requirements are speculative”. Since then, a lot of scholars have employed financial information in predicting abnormal returns successfully, among them, Ou and Penman (1989) Through conducting financial statement information in some models, to predicting abnormal returns in Chinese stock market, we examine whether its usefulness in Chinese Manufacturing Companies and found that it was impossible to predict stock performance in the Chinese market which was proved useful in other stock market.
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Grabot, B., D. Noyes, and D. Riopel. "On the Abnormal Operating Modes Management in a Transportation System." IFAC Proceedings Volumes 28, no. 11 (June 1995): 163–68. http://dx.doi.org/10.1016/s1474-6670(17)46966-7.
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Luo, Rui Meng, and Jin Yong Yao. "The Reliability Analysis of Multi-Operation State Repairable System." Applied Mechanics and Materials 184-185 (June 2012): 1608–12. http://dx.doi.org/10.4028/www.scientific.net/amm.184-185.1608.
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To describe precisely the performance characteristics of Markov repairable systems, the model of Markov repairable systems with multi-operating state was introduced. There are three kinds of states of the system: normal, abnormal and fault state. The system works when it is in the normal state and abnormal state, it stops to be mended till it is inspected and diagnosed in abnormal state or something wrong happens in it. Inspect it at intervals after it begins to work in the normal state until it is inspected and diagnosed in abnormal state or it fails. The life of the system, inspection time intervals and repairing time follow exponential distribution, we build the Markov mathematic model to the system. The steady-state reliability and the expression of steady-state yield are derived by using the Markov process method. The study of numerical examples has shown that optimal inspection strategy can increase the system economic effectiveness.
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Brycheva, A. Yu, and V. D. Molyakov. "The Choice Gas Turbine Engine Parameters Used to Drive the Oil Pump." Mechanical Engineering and Computer Science, no. 11 (December 22, 2017): 29–43. http://dx.doi.org/10.24108/1117.0001307.
Full textAbstract:
The article considers capabilities of the gas turbine engine to be used as a drive of the crude oil pump. It is noted that the gas turbine drive proves to be more advantageous than the electric motor when there is no external power supply or building periods of power transmission lines are significantly long, as well as quantities of oil products pumped are often changed.The main objective of this work is to select the optimum engine cycle parameters for a particular pump model, which oil pumping stations use. As an object of research, a crude oil pump of the НМ 10000 / 1.25-210 brand was chosen. The paper presents technical characteristics of the HM 10000 / 1.25-210 centrifugal pump and experimental values of head, power, and efficiency of the pump for a number of feeds. To obtain the pressure and power characteristics of a centrifugal pump for different rotational speeds of the rotor the similarity formulas are used.As the centrifugal pump drive, the paper considers a two-shaft plant with the free power turbine. This scheme was chosen in accordance with the features of the gas turbine pump unit at the oil pumping station. It is noted that the free power turbine scheme allows us to bring into accordance the characteristics of a gas turbine engine and an oil pump in abnormal modes, since there is no mechanical connection between high and low pressure turbines.The paper presents the calculated parameters of the gas turbine engine cycle with power Ne = 8 MW. The graphs show dependence of the airflow rate GB, the specific fuel consumption Ce and the efficiency ηe on the degree of pressure increase πk in the compressor. In accordance with the graphs, the optimum value of the degree of pressure increase πk = 15 in the compressor is adopted. With πk = 15, the specific fuel consumption in the gas turbine engine with power Ne = 8 MW is equal to Ce = 0,22 kg/kW*h and the airflow rate is GB = 20,5kg/s. The efficiency of the engine with the selected parameters is ηe = 38,4%.It is noted that in order to ensure the most economical gas turbine engine operation, it is necessary to select the optimal control program, which is determined taking into account the load characteristics, in this case the characteristics of the pump.
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Al-Sinbol, Ghassan, Mario G. Perhinschi, and Brenton K. Wilburn. "Simplified GPS model for UAV fault tolerant control laws design." International Journal of Intelligent Unmanned Systems 3, no. 1 (February 9, 2015): 39–60. http://dx.doi.org/10.1108/ijius-09-2014-0007.
Full textAbstract:
Purpose – A simplified global positioning system (GPS) error model including models for a variety of abnormal operational conditions and failures is developed to provide simulation tools for the design, testing, and evaluation of autonomous flight fault tolerant control laws. The paper aims to discuss these issues. Design/methodology/approach – Analysis and experimental data are used to build simplified models for GPS position and velocity errors on all three channels. The GPS model is interfaced with West Virginia University unmanned aerial vehicles (UAV) simulation environment and its utility demonstrated through simulation for several autonomous flight scenarios including GPS abnormal operation. Findings – The proposed simplified GPS model achieves desirable levels of accuracy and realism for all components for the purpose of general UAV dynamic simulation and development of fault tolerant autonomous flight control laws. Research limitations/implications – The simplified GPS model allows investigating GPS malfunction effects on the performance of autonomous UAVs and designing trajectory tracking algorithms with advanced fault tolerant capabilities. Practical implications – The simplified GPS model has proved to be a flexible and useful tool for UAV simulation and design of autonomous flight control laws at normal and abnormal conditions. Originality/value – The outcomes of this research effort achieve a level of detail never attempted before in modeling GPS operation at normal and abnormal conditions for UAV simulation and autonomous flight control laws design using a simplified framework.