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1
Larson, D. L. "Performance of the Coolidge Solar Thermal Electric Power Plant." Journal of Solar Energy Engineering 109, no. 1 (February 1, 1987): 2–8. http://dx.doi.org/10.1115/1.3268173.
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Energy performance and equipment evaluation results are presented for the grid-connected Coolidge solar thermal-electric power plant. Performance was determined for each of the major subsystems—line-focus collector array, thermal energy storage and 200 kW, organic Rankine cycle engine and generator. Day-long collector array efficiency was about 32, 26, and 9 percent in June, September, and December, respectively. Energy conversion efficiency was about 20 percent; electrical parasitics reduced this by 12 percent. Operation and maintenance required about 90 h/mo, only 20 percent requiring special skills or training. Operating supplies and repair services cost about $6300 per year. Major equipment problem catagories were fluid leakage and electric motor and electronic component failures. The presented operating data provide a basis for improved design and analysis.
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Vukosavic, Slobodan, Nikola Popov, and Zeljko Despotovic. "Power electronics solution to dust emissions from thermal power plants." Serbian Journal of Electrical Engineering 7, no. 2 (2010): 231–52. http://dx.doi.org/10.2298/sjee1002231v.
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Thermal power stations emit significant amounts of fly ash and ultra fine particles into the atmosphere. Electrostatic precipitators (ESP) or electro filters remove flying ashes and fine particles from the flue gas before passing the gas into the chimney. Maximum allowable value of dust is 50 mg/m3 and it requires that the efficiency of the ESPs better than 99 %, which calls for an increase of active surface of the electrodes, hence increasing the filter volume and the weight of steel used for the filter. In previous decades, electrostatic precipitators in thermal power plants were fed by thyristor controlled, single phase fed devices having a high degree of reliability, but with a relatively low collection efficiency, hence requiring large effective surface of the collection plates and a large weight of steel construction in order to achieve the prescribed emission limits. Collection efficiency and energy efficiency of the electrostatic precipitator can be increased by applying high frequency high voltage power supply (HF HV). Electrical engineering faculty of the University of Belgrade (ETF) has developed technology and HF HV equipment for the ESP power supply. This solution was subjected to extensive experimental investigation at TE Morava from 2008 to 2010. High frequency power supply is proven to reduce emission two times in controlled conditions while increasing energy efficiency of the precipitator, compared to the conventional thyristor controlled 50Hz supply. Two high frequency high voltage unit AR70/1000 with parameters 70 kV and 1000 mA are installed at TE Morava and thoroughly testes. It was found that the HF HV power supply of the ESP at TE Morava increases collection efficiency so that emission of fine particles and flying ashes are halved, brought down to only 50 % of the emissions encountered with conventional 50 Hz thyristor driven power supplies. On the basis of this study, conclusion is drawn that the equipment comprising HF HV supplies are the best solution for new ESP installations, as well as for the reconstruction of existing facilities. The paper describes the topology of the HF HV power supply, power management and controls, and brings the most important details of the implementation. It is found that the HF HV solution achieves several significant improvements over the conventional thyristor system. It is possible to provide more precise control of the ESP parameters such as the output voltages and currents. It is also possible to make a rapid increase or decrease in voltage and to effectuate a very fast response to load changes. Due to this advantages it is possible to suppress the supply quickly in the case of sparking, reducing the spark energy and the quantity of ionized gasses produced by the electric arc. Reduction in the spark energy is up to 10 times compared to conventional thyristors solution. This means that the erosion of the electrode system is significantly reduced, and that the quality of the collection plates is preserved for much longer periods. At the same time, lower quantity of ionized gasses produced by the spark contribute to much shorter deionization intervals, required to quit sparking and evacuate charged particles in order to reinstate the voltage and proceed with the operation. In addition, HF HV power supply provides a significant reduction in size and weight of the complete ESP installation, hence reducing the tons of steel that has to be built in. Therefore, the HF HV power supply may be the key instrument to reducing the cost of the dedusting ecological equipment. Besides, size and weight reduction leads to cost savings of installation and maintenance. According to estimates, savings in steel may reach 30%, contributing to the overall cost savings of roughly 20%. Within this paper, in addition to describing the AR70/1000 unit topology and principles of operation, the paper presents the results and measurements obtained during extensive experimental investigations wherein performances of 50 Hz based thyristor units with T/R sets are compared to HF HV power supply.
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Ariyarathna, Thilanga, Nihal Kularatna, and D. Alistair Steyn-Ross. "Transformer Isolated SCALDO Based High Current DC Power Supply." Applied Mechanics and Materials 884 (August 2018): 122–28. http://dx.doi.org/10.4028/www.scientific.net/amm.884.122.
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With increasing component count inside the microprocessor, computer has become a power hungry device and powering IT equipment is one of the largest operating expenses and challenge for data centre in USA. According to the data published by Electric Power Research Institute (EPRI), USA global data centres cloud power market is expanding at over 10 percent annually to reach 200 billion kilowatt-hour energy consumption by 2020. Reducing power loss by 1% inside a server power supplies could result in 2 billion kilowatt-hour energy saving.SCALDO is a patented technique developed by the power electronics research group, University of Waikato which improves the efficiency of low drop-out regulators. This technique can be used inside silver box power supplies to enhance the quality of the output power. Practically realising some SCALDO configuration is challenging due to its large switch count. Novel power converter topology presents in this paper helps SCALDO to be used efficiently inside silver box power supplies with electrical isolation and reduced number of switches.
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Zhao, Ke, Song Bai He, Qi Zhi Huang, and Liang Zhang. "Research and Development of Engine-Generator Set Control System for Tracked Vehicle Electric Transmission System." Advanced Materials Research 546-547 (July 2012): 949–54. http://dx.doi.org/10.4028/www.scientific.net/amr.546-547.949.
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As an energy generating equipment, the engine-generator set supplies power to the electric transmission. Therefore, its control is one of the key technologies of electric vehicles. Based on the discussion about the demands to the engine-generator set in tracked vehicles, the detailed function of engine-generator and the contro1 strategy are determined. The hardware and software of the control system are also developed and tested in a prototype vehicle. The experiment results show that the control system has good reliability and can satisfy the power requirements of vehicles under all operating conditions.
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Suprianto. "The Implementation of ATS (Automatic Transfer Switch) System Between Solar Power Plants and Grid Systems for the Household Electric Power Service to Maintain Sustainability and Save Electricity Costs." Journal of Computational and Theoretical Nanoscience 17, no. 7 (July 1, 2020): 3136–40. http://dx.doi.org/10.1166/jctn.2020.9150.
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The continuity of electric power service is a major factor determining electrical customer satisfaction. Research on the implementation of the ATS system between solar cells and grid system as a supplier of electrical power to household electrical loads for continuity and savings in electricity consumption costs aims to design an ATS system for delivering electrical power to the load system that can maintain the continuity of the supply of electricity, reducing costs electricity consumption while reducing dependence on grid electricity supply. The specific target to be achieved in this research is to design an ATS system for the distribution of electric power between grid system and solar power system and find out the cost of savings while maintaining continuity of electricity services, so that electricity consumers can benefit from technical and economic aspects. The method used in this study is an experimental method that is designing an electrical power supply ATS system to get the results of a good design and as planned. The equipment used is solar panels, relays, timers, inverters, household electrical loads, contactors, electrical measuring devices, temperature gauges and light intensity, battery systems and control panels. The results showed that the automatic transfer switch must attention to the design of an accurate and meticulous to avoid damage to the inverter. So that continuity of service of electric power is maintained. Electric power service using a solar cell system with 2 units of 100 Ah batteries and 6 units of 100 Wp solar panels can serve household electrical loads for 1 day of battery charging and discharging, 1 day of battery charging and 1 day of battery discharging with average electric energy generated at 1485 W-hours. Costs can be saved in 1 month if the price of electricity is Rp. 1352/Kwh, is Rp. 20,104.-/month with an investment cost of Rp. 27,956,000.
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Zhdanova, Olga Aleksandrovna, Tatiana Grigorievna Bondarenko, Margarita Vasilievna Pashkovskaya, and Svetlana Vladimirovna Plyasova. "Russian-Chinese Cooperation Prospects in the Electric Power Industry." Revista Amazonia Investiga 9, no. 27 (March 21, 2020): 570–77. http://dx.doi.org/10.34069/ai/2020.27.03.61.
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Russia and China have long been trading partners and cooperated in most industries, including the electric power sector. Even with close and long-standing ties, the further scope of Russian-Chinese relations in the electric power sector should be defined taking into account China's currently implemented Belt and Road Initiative requiring enormous resources, particularly in commodities. An analysis of Russia's electric power market shows an imbalance between the levels of demand and supply skewing to the supply side. Russian excess supply of electricity could be feasibly channelled to China under long-term contracts. For now, such supplies have not been operated at the levels planned several years ago, which indicates low utilisation of the existing potential of cooperation between the countries in the sector. Besides, considerable potential exists for partnership between Russia and China in upgrading electric power facilities and supplying electricity equipment and its subsequent maintenance.
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Buratynskyi, I. M., and T. P. Nechaieva. "Modeling of the combined operation of a solar photovoltaic power plant and a system of electric energy storage." Problems of General Energy 2020, no. 3 (September 24, 2020): 30–36. http://dx.doi.org/10.15407/pge2020.03.030.
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In view of the dependence of power generation at photovoltaic solar power plants on the level of intensity of solar radiation and cloud cover, their operation creates a number of problems in the power system. This article describes the problems of operation of such power plants of non-guaranteed capacity during their parallel operation as a part of the Unified Energy System of Ukraine. One of the measures of stabilizing the operation of power plants of non-guaranteed capacity is the use of systems of electric energy storage. The article describes the conditions of electrical connection, which ensure the possibility of combined operation of a system of electric energy storage and a photovoltaic solar power plant. The article presents the developed mathematical model of the combined operation of a photovoltaic solar power plant (PSPP) and a system of electric energy storage. We consider the daily mode of recharging from a PSPP and discharging batteries into the power system in order to preserve the excess of generated electricity at the PSPP, which earlier was lost due to the restriction on inverters caused by the overload with photovoltaic power. The model enables one to identify the key parameters of batteries – power and capacity, taking into account the physical and technical features of the operation of battery storage as to the conversion efficiency, the number of working cycles and the depth of possible discharge depending on the structure of PSPP equipment and solar radiation intensity. Using the developed model, we determined the values of power, charging and discharging capacities of a lithium-ion system for storing electrical energy, when it works together with a 10 MWAC photovoltaic solar power plant at different overload factors. The article presents some results of technical and economic assessment of the combined operation of a PSPP and a lithium-ion system for storing electrical energy. The results showed an increase in the power and capacity of a storage device with increase in the overload factor of PSPP, which leads to the growth of cost of electrical energy at their combined work. At the same time, the amounts and quality of electricity supplied increase. Keywords: mathematical model, photovoltaic solar power plant, system of electric energy storage, cost of electricity, power system
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Kai, Tatsuro, Takashi Ukai, Muneo Ohta, and Ernesto Pretto. "Hospital Disaster Preparedness in Osaka, Japan." Prehospital and Disaster Medicine 9, no. 1 (March 1994): 29–34. http://dx.doi.org/10.1017/s1049023x00040802.
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AbstractPurpose:To investigate the adequacy of hospital disaster preparedness in the Osaka, Japan area.Methods:Questionnaires were constructed to elicit information from hospital administrators, pharmacists, and safety personnel about self-sufficiency in electrical, gas, water, food, and medical supplies in the event of a disaster. Questionnaires were mailed to 553 hospitals.Results:A total of 265 were completed and returned (Recovery rate; 48%). Of the respondents, 16% of hospitals that returned the completed surveys had an external disaster plan, 93% did not have back-up plans to accept casualties during a disaster if all beds were occupied, 8% had drugs and 6% had medical supplies stockpiled for disasters. In 78% of hospitals, independent electric power generating plants had been installed. However, despite a high proportion of power-plant equipment available, 57% of hospitals responding estimated that emergency power generation would not exceed six hours due to a shortage of reserve fuel. Of the hospitals responding, 71% had reserve water supply, 15% of hospitals responding had stockpiles of food for emergency use, and 83% reported that it would be impossible to provide meals for patients and staff with no main gas supply.Conclusions:No hospitals fulfilled the criteria for adequate disaster preparedness based on the categories queried. Areas of greatest concern requiring improvement were: 1) lack of an external disaster plan; and 2) self-sufficiency in back-up energy, water, and food supply. It is recommended that hospitals in Japan be required to develop plans for emergency operations in case of an external disaster. This should be linked with hospital accreditation as is done for internal disaster plans.
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Suhanto, Suhanto. "SIMULASI AUTOMATIC TRANSFER SWITCH DAN AUTOMATIC MAINS FAILURE DENGAN PLC OMRON SYSMAC CP1E." Journal of Mechanical Engineering and Mechatronics 4, no. 1 (April 11, 2019): 27. http://dx.doi.org/10.33021/jmem.v4i1.662.
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<p>Electric power supply is the main requirement of equipment at the airport, therefore the reliability of the supply of power supplies is a top priority to support flight services. In addition to PLN as the main power supply the generator is used to supply a backup power supply. Automatic Transfer Switch (ATS) and Automatic Mains Failure (AMF) control systems are needed to regulate the switching of power supplies from PLN to Genset or vice versa. The ATS and AMF control systems use the Omron Sysmac CP1E PLC with a display using Easy Builder 8000 from Weintek which functions as an ATS and AMF monitor and control. Test results on ATS and AMF in manual and automatic modes, the system runs well.<br />Keywords. Automatic Transfer Switch (ATS), Automatic Mains Failure (AMF), PLC</p>
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Howard, Matt, J. Bakker-Dyos, L. Gallagher, J. P. O’Hara, D. Woods, and A. Mellor. "Power supplies and equipment for military field research: lessons from the British Service Dhaulagiri Research Expedition 2016." Journal of the Royal Army Medical Corps 164, no. 1 (December 25, 2017): 41–45. http://dx.doi.org/10.1136/jramc-2017-000767.
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IntroductionThe British Service Dhaulagiri Research Expedition (BSDMRE) took place from 27 March to 31 May 2016. The expedition involved 129 personnel, with voluntary participation in nine different study protocols. Studies were conducted in three research camps established at 3600, 4600 and 5140 m and involved taking and storing blood samples, cardiac echocardiography and investigations involving a balance plate. Research in this remote environment requires careful planning in order to provide a robust and resilient power plan. In this paper we aim to report the rationale for the choices we made in terms of power supply, the equipment used and potential military applicability.MethodsThis is a descriptive account from the expedition members involved in planning and conducting the medical research.ResultsPower calculations were used to determine estimates of requirement prior to the expedition. The primary sources used to generate power were internal combustion engine (via petrol fuelled electric generators) and solar panels. Having been generated, power was stored using lithium-ion batteries. Special consideration was given to the storage of samples taken in the field, for which electric freezers and dry shippers were used. All equipment used functioned well during the expedition, with the challenges of altitude, temperature and transport all overcome due to extensive prior planning.ConclusionsPower was successfully generated, stored and delivered during the BSDMRE, allowing extensive medical research to be undertaken. The challenges faced and overcome are directly applicable to delivering military medical care in austere environments, and lessons learnt can help with the planning and delivery of future operations, training exercises or expeditions.
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Lipták, Peter, Ivan Kopecký, Ján Štrba, and Ivan Dlugoš. "The Need Of Special Technique In Crisis Management." TRANSACTIONS of the VŠB – Technical University of Ostrava, Safety Engineering Series 10, no. 2 (September 1, 2015): 41–47. http://dx.doi.org/10.1515/tvsbses-2015-0012.
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Abstract Operation of special equipment is possible in crisis situations. It is because special equipment is designed for operation in non-standard often extreme conditions and situation, it is available, it has a high degree of crossing capability and it is able to provide basic living conditions even in field, e.g. provision of power for hospital, transportation of wounded and injured persons, supplies, medical care in field conditions, delivery of potable and utility water etc. The authors in the paper deal with a possibility to provide electric energy through advanced renewable sources, especially in meeting tasks in areas with no public mains, possible supplies of potable and non-potable water, embedding such assets into mobile systems. The authors in publication summarize results of research within the „Use of renewable sources of energy in practice project“. System of modeling and computer-aided simulation of renewable sources of energy has been proposed within this project. Application of a system for designing of power systems in logistic containers is expected. The knowledge on power balance of logistic containers operated by the SR Armed Forces in missions abroad is summarized in the last chapter of the paper. Experiences with operating the equipment in crisis and extreme conditions have proved a possibility to export and deploy machines and weaponry equipment of the SR Armed Forces into extreme climatic conditions, e.g. out of European conditions etc.
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Xu, Xin, and Guang Qing Bao. "Coordination Controlling of Micro-Grid with EVs." Advanced Materials Research 608-609 (December 2012): 1660–64. http://dx.doi.org/10.4028/www.scientific.net/amr.608-609.1660.
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Electric vehicles (EVs) play dual roles in micro-grids. They can be seen as a Vehicle to Grid load when in charge. While their powers are enough for moving, they can be seen as power supplies. In this paper, the optimization of distributed energies is discussed in a micro-grid, basing on multi-agent system (MAS). The result shows that the micro-grid with electric vehicles can not only make the most optimal use of renewable energies in the premise of keeping the voltage stability, but also reduces the investment of energy storage equipment. And with reasonable energy exchange prices, the electric vehicle owners can save their costs.
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Jettanasen, Chaiyan, and Atthapol Ngaopitakkul. "The Conducted Emission Attenuation of Micro-Inverters for Nanogrid Systems." Sustainability 12, no. 1 (December 23, 2019): 151. http://dx.doi.org/10.3390/su12010151.
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Road lighting systems require a significant amount of electric energy. To compensate for the utilized energy, the concept of a nanogrid road lighting system is presented. A solar panel is installed on the top of a lighting pole to generate electric power. In this research, a photovoltaic simulator (PV simulator), which is used to simulate solar behavior such as current, voltage, and power based on temperature and solar irradiance levels, is employed to replace a solar panel. In the nanogrid system, grid-connected and stand-alone micro-inverters are employed to convert the electric power. The inverters comprise switching devices that can generate electromagnetic interference (EMI) when operating, which is harmful to the grid system and the electrical equipment. In general, EMI has been studied and reduced in electrical appliances, which only receive electric power. However, for the nanogrid system, which supplies electricity to the grid system, there is less study on the EMI topic because the usage is still not widespread. In the future, the nanogrid system will be widely used delivering high power directly into the electrical grid system. Therefore, the study and attenuation of EMI in the nanogrid system are very promising. Conducted emission (CE) is one form of EMI that flows through a cable connecting several appliances in the frequency range of 150 kHz to 30 MHz. CE of grid-connected and stand-alone micro-inverters have high levels in the low-frequency range between 150 kHz–5 MHz and then decreases steadily. CE attenuation is important for this inverter in a solar power system. This research studies the effect of CE mitigation on the nanogrid system. The result is compared with the Comité International Spécial des Perturbations Radio (CISPR) 14-1 standard. Finally, the passive EMI filter can reduce CE and meets the CISPR 14-1 standard.
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Borzea, Claudia, Iulian Vlăducă, Dan Ionescu, Valentin Petrescu, Filip Niculescu, Cristian Nechifor, Gabriel Vătăşelu, and Mihai Hanek. "Compressed Air Energy Storage Installation for Renewable Energy Generation." E3S Web of Conferences 112 (2019): 02010. http://dx.doi.org/10.1051/e3sconf/201911202010.
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Compressed Air Energy Storage (CAES) installations are used for storing electrical power, under the form of potential energy from compressed air. The heat generated during compression can be stored to improve the efficiency of compression-expansion cycle. The solution presented consists of a 100 kW screw compressor driven by a 110 kW asynchronous three-phase motor. The compressor supplies air into vessels which store it until a high electrical energy demand arises. At that time, the compressed air is released into a 132 kW screw expander whose shaft spins a 132 kW asynchronous generator, producing electric power and supplying it into the electrical grid. Before expansion, the air must be preheated in order to avoid the freezing of expansion equipment. If the heat generated during compression is used for air preheating before expansion, the process is adiabatic. A demonstrative model of the installation is currently being developed, with the expander part being completed so far. The maximum power to be produced was calculated to be around 100 kW. During expander commissioning tests with air supply from a 250 kW high pressure compressor, a maximum generated power of 49.7 kW was attained, expected to be higher when releasing air from the reservoirs.
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Khodakovskyi, Oleksii, Larysa Levchenko, Vadym Kolumbet, Anna Kozachuk, and Dmytro Kuzhavskyi. "Calculation apparatus for modeling the distribution of electromagnetic fields of different sources." Advanced Information Systems 5, no. 1 (June 22, 2021): 34–38. http://dx.doi.org/10.20998/2522-9052.2021.1.04.
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The calculation apparatus acceptable for assumptions and simplifications and sufficient for errors of final results for modeling the propagation of electric, magnetic and electromagnetic fields spread over a certain area was proposed. It is shown that to model the propagation of ultra-low frequency electric and magnetic fields (monitors, uninterruptible power supplies, transformers, electric motors and generators) it is possible to consider these sources as dipole and dipole-quadrupole type sources. That is, the field of the local source can be considered as a combination of electric and magnetic dipoles. This makes it possible to delineate with sufficient accuracy the zones of exceeding the maximum allowable field strengths. The calculation apparatus used to determine the radiation intensities of civil aviation radar equipment was adapted to model the propagation of electromagnetic fields of very high and ultra-high frequencies. The calculations of coefficients that take into account the parameters of radiation patterns in the horizontal and vertical planes for the most common radiation sources are given. These ratios and corresponding coefficients can be used to determine the electromagnetic environment in the presence of many high-frequency sources (mobile communication base stations, navigation equipment, radio relay stations, etc.). The proposed approach allows to automate processes of designing the placement of electromagnetic, electronic and radio equipment in production areas and territories, as well as to assess the environmental impact at the stages of design work. This will make it possible to delineate the isolines of the limits of exceeding the maximum permissible levels of electric magnetic and electromagnetic fields for different frequency ranges and categories of equipment and to automatically determine the electromagnetic load at each point of the controlled space.
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Gallego, A. G., A. C. C. Souza, P. H. Morais, and M. Modesto. "THERMODYNAMIC ANALYSIS OF ELECTRIC POWER PRODUCTION TECHNOLOGIES IN COGENERATION SYSTEMS ON FPSO AIMING TO REDUCE CO2 EMISSIONS." Revista de Engenharia Térmica 20, no. 1 (April 12, 2021): 58. http://dx.doi.org/10.5380/reterm.v20i1.80454.
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Oil platforms are complex structures used to host workers and equipmentneeded in offshore exploration. This study focuses on the platform's heatand electricity cogeneration plant, which supplies a process heat exchangersnet, and provides the necessary electricity for all the equipment used for theprocess and worker's accommodation in the platform. The platform demandwith maximum load is 75 MW, which could be achieved using four gasturbines (25 MW each), one of which is kept for backup purposes or usingsix dual-fuel engines diesel/natural gas (15 MW each), one of which is alsokept for backup purposes. Therefore, the thermodynamic analysis wasperformed - considering five specific demand points of the platform -comparing the two traditional configurations (gas turbines and dual-fuelengines diesel/natural gas) and a combined configuration. The combinedconfiguration is composed of three gas turbines and two dual-fuel enginesdiesel/natural gas (one of the gas turbines kept for backup purposes). Theconfigurations presented respectively 35.5%, 48.4% and 42.6% at highestoverall efficiency; 611.34 g/kWh, 373.45 g/kWh, 472.74 g/kWh at lowestCO2 emissions considering full attendance of electrical and thermaldemands. The configurations using only gas turbines and the combinedfully attended the thermal demand of the platform without using auxiliarypieces of equipment. Therefore, it was possible to observe that thecombined configuration presented several advantages concerning isolatedsystems, proving to be an excellent option for sustainable energygeneration, reducing emissions of polluting gases and greater flexibility ofits operation concerning to configuration only with turbines, and physicaloccupation in relation to configuration only with engines.
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ZHUSUBALIYEV, ZHANYBAI T., EVGENIY A. SOUKHOTERIN, VADIM N. RUDAKOV, YURI V. KOLOKOLOV, and ERIK MOSEKILDE. "BIFURCATIONS AND CHAOTIC OSCILLATIONS IN AN AUTOMATIC CONTROL RELAY SYSTEM WITH HYSTERESIS." International Journal of Bifurcation and Chaos 11, no. 05 (May 2001): 1193–231. http://dx.doi.org/10.1142/s0218127401002699.
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The dynamics of relay system with hysteresis is investigated. Systems of this type have a broad range of applications for power control and temperature regulation or in order to obtain highly stabilized electric or magnetic fields. Examples are power supplies for radio-electronics, computer equipment or spacecrafts, test stands for investigations of high- or low-temperature superconductivity, electron microscopes, and nuclear magnetic resonance tomographs. We first describe a general approach to determine stable and unstable periodic orbits for systems with hysteresis. Considering a concrete example of a four-dimensional relay system with hysteresis we hereafter determine the regions of periodic and chaotic oscillations in parameter space. The regularities in the occurrence of periodic motions are studied, and the associated bifurcations are described. The causes of nondeterminate (i.e. chaotic) dynamics are discussed and the influence of an external noise signal is analyzed.
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Henriques, Henrique Oliveira, Carlos Eduardo Vizeu, Paulo Cesar Souza, Mauricio Caldora Costa, Guilherme Gonçalves Sotelo, Jonaylton Moura Sousa, Marcio Zamboti Fortes, and Vitor Hugo Ferreira. "COUPLED ELECTROMAGNETIC-THERMAL SIMULATION OF A POWER TRANSFORMER BY 3D FEM." Acta Polytechnica 60, no. 5 (November 16, 2020): 400–409. http://dx.doi.org/10.14311/ap.2020.60.0400.
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Power transformers are the most common equipment in an electric power system, which has been manufactured in the last decade. However, overheating can damage them, considerably reducing their operation lives, which may cause economic losses to the power utilities. The motivation of this paper is to investigate the time and power overload limits that a power transformer can be subjected to and how it will impact its temperature. Investments in the grid can be delayed if a transformer can support some overload during some momentary load demand increase. In this context, this paper presents a study of a 30/40MVA power transformer by 3D finite element method (FEM) for coupled thermal-electromagnetic simulations to investigate its thermal behaviour when it is submitted to its nominal load at a steady-state operation and a variable load during a period of one day. The simulations were performed with the commercial software packages Flux 3D and AcuSolve, for electromagnetic and thermal modelling, respectively. The modelled equipment was based on a power transformer installed in the Light Serviços de Eletricidade S.A, the utility that supplies electrical energy to the city of Rio de Janeiro, in Brazil. Since the literature doesn’t present many works simulating coupled thermal-electromagnetic power transformers in 3D-FEM, this paper has the goal to bring new contributions to this field. Three study cases were modelled, and some simplifications in transformer’s geometry were made in some of them to reduce the computation time usually required for such a simulation. The obtained results are presented and compared with the measured values for the temperature in the hot spot of the transformer and in the top of the oil, to investigate the impact of these simplifications in the calculated results.
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GUSAROV, VALENTIN. "THE PROSPECT OF USING OWN TPP IN POWER SUPPLY OF FEDERAL SCIENTIFIC AGROENGINEERING CENTER VIM." Elektrotekhnologii i elektrooborudovanie v APK 4, no. 41 (December 2020): 9–16. http://dx.doi.org/10.22314/2658-4859-2020-67-4-9-16.
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As industrial production expands, infrastructure develops, and new technological equipment is put into operation, energy needs increase, which means that the role of reliable energy supply to industrial enterprises increases. Electricity is used to light the territory of the enterprise, workshops, and laboratories, operate machines and mechanisms, automatically control the heat supply of premises and other technological processes. The level of reliability and security of heat and electricity supplies determines the stability of the enterprise and its economic efficiency. (Research purpose) The research purpose is in studying the economic efficiency of using own thermal power plant based on a gas turbine power unit. (Materials and methods) The article presents the advantages of using own thermal power plant that runs on natural gas. The most efficient balance of heat and electric energy production was determined. (Results and discussion) The article presents the construction of thermal power plant for the heat supply of buildings and structures defined by the project on the territory of the Federal Scientific Agroengineering Center VIM. The article considers the emerging trend of industrial enterprises building their own power plants, which make it possible to provide themselves with heat and electricity independently and guarantee more reliable operation of workshops by reducing downtime and disruptions of technological processes. (Conclusions) The use of a thermal power plant based on a gas turbine power unit will allow to get an annual profit, ensure energy independence, increase the reliability of power supply, and increase the profitability of production. Many large enterprises, pursuing economic goals, along with their own electricity supply, supply «excess» energy to centralized networks, often the level of energy supply «for export» significantly exceeds the level of their own consumption.
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Pham, Tan. "Earthquake reconnaissance report." Bulletin of the New Zealand Society for Earthquake Engineering 25, no. 1 (March 31, 1992): 3–16. http://dx.doi.org/10.5459/bnzsee.25.1.3-16.
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The magnitude 7.1 Loma Prieta earthquake, at 5.04 pm on 17 October 1989, caused deaths, damage to properties and disrupted transportation, utilities and communications. Electricity and gas in the area affected by the earthquake were supplied by Pacific Gas and Electric (PG&E) Company which served more than 10 million people in northern and central California. The company's 1988 annual report showed a total sale of 68537 GWh of electricity. The earthquake caused considerable damage to power generation facilities at Metcalf, San Mateo and Moss Landing. Facilities at Potrero and Hunter Points also experienced minor damage. Damage occurred to old items of equipment which were not designed to PG&E's current seismic specifications. Those which were located on sites near the epicentre of the earthquake suffered the most damage. According to PG&E's report, issued soon after the earthquake, about 1.4 million PG&E customers lost electric power, some for up to 48 hours, and a total cost of damage between US $30 millions and US $50 millions has been estimated. There were other smaller power generation plants in the area besides those owned by PG&E. Most were built recently and, to the author's knowledge, they suffered little damage during the earthquake.
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Jeong, In Wha. "DC-Link Capacitor Voltage Balancing Control of a Five-Level Regenerative AC Electronic Load Using One-Cycle Control." Energies 14, no. 19 (September 24, 2021): 6101. http://dx.doi.org/10.3390/en14196101.
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High voltage electric power equipment requires rigorous regulation testing to specific standards which ensure proper and safe operation in the grid. Manufacturers conduct these tests in order to prove standard compliance and product liability. Variable linear or nonlinear loads are necessary for testing medium voltage (MV) high power AC power converters. Generally, those AC power converters or power supplies require performance validation, burn-in and/or lifetime testing under different load conditions, defined by the end-user or standards for the given applications. For flexible and efficient MV verification testing, this paper presents a five-level multilevel converter-based MV regenerative AC electronic load with one-cycle control (OCC), which is based on five-level diode-clamped multilevel converters with back-to-back structure and can emulate any impedance load. In this paper, especially the dc-link capacitor voltage balance of the proposed multilevel MV regenerative AC load is deeply analyzed. Simulation and experimental results are presented to verify the dc-link voltage balance performance of the proposed multilevel MV regenerative AC electronic load.
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Riddex, Louis, and Uno Dellgar. "The Ice Storm in Eastern Canada 1998 KAMEDO-Report No. 74." Prehospital and Disaster Medicine 16, no. 1 (March 2001): 50–52. http://dx.doi.org/10.1017/s1049023x00025589.
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AbstractThis is a report of the impact of the ice storm that struck eastern Canada on 04–09 January 1998. The storm deposited ice some 100 mm thick on the ground and on the electric power lines and eventually left 1.4 million households and much of the infrastructure without electrical power.Data were obtained through non-structured interviews of those involved. Most of the larger hospitals were equipped with emergency generating equipment and were able to provide most essential services. For most hospitals, non-emergency services were compromised. Many other medical facilities, including clinics had to be shut down, and smaller hospitals were forced to transfer some patients to larger institutions. In addition, hospitals experienced a marked increase in the number of emergency department visits including an increase in the number of persons with injuries, respiratory tract infections, or heart problems. A marked increase in carbon-monoxide intoxication was observed: 50 persons required the use of hyperbaric oxygen and six persons died of CO poisoning.Prehospital services not only experienced a marked increase in the number of emergency responses, but also were utilized to provide transportation of non-ill or injured persons, equipment, and supplies. Home care was interrupted and many patients dependent upon power had to be transported to hospitals. Many hospitals opened their buildings to provide shelter to the families of many of their employees and medical staff. This helped to keep staffing at a better level than if they had to find shelter and essential services elsewhere.The transmission and sharing of information was severely limited due in part to the loss of power and inability to access television. This led to the distribution of misleading or incorrect information.This storm was exemplary of our dependence upon electrical power and that we are not prepared to cope with the loss of electricity.
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Kokoev, M. N., V. T. Fedorov, and G. N. Hadgishalapov. "WIND ENERGY IN THE MANUFACTURE OF PENOSTEKL AND KERAMZIT." Herald of Dagestan State Technical University. Technical Sciences 46, no. 1 (July 16, 2019): 187–94. http://dx.doi.org/10.21822/2073-6185-2019-46-1-187-194.
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Objectives. Foamglass and expanded clay are absolutely fireproof, reliable and environmentally friendly heat insulators. But in the cost of their production, energy costs reach 40 ... 60%.Method. A part of the thermal energy required for the production of building materials was proposed to be developed by a wind power station (WPP).Result. A heating plant with a Darya turbine capable of operating in severe climatic conditions has been developed. The bearing part of the wind power installation consists of three simple masts, working mainly in compression. The masts are symmetrically placed relative to the center of the wind farm. The design feature is that the vertical shaft with the turbine is suspended at the top of the swivel at the point where the three almost horizontal cables meet. The free ends of the ropes pass through the blocks on the tops of the masts and are secured with anchors at ground level. Therefore, the shaft works mainly in tension and torsion and is well opposed to transverse vibrations. A simple generator without equipment for voltage and frequency regulation operates at WPPs, as for electric heaters of furnaces to which the generator current is supplied, power conditioning is not required. With a decrease in wind speed and a drop in HPP power, the automation supplies more fuel to the burners to maintain the temperature according to the regulations.Conclusion. Thus, the WPP capacity fills a part of the required heat output of the furnaces, and the missing part of the heat output is compensated by burning gas or fuel oil. If the WPP is located near the enterprise, then electricity is supplied to the consumer without transformers. It is cheaper to lay cables of a larger section than to complete a wind farm with two power transformers.
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Hong, Dae Sun, Do Un Kim, Hyo Jeong Kang, Sang Wook Hwang, and Sang Sik Lee. "Finite Element Analysis on a 250 kN.m-Type Rotary Drilling Rig for Foundation of Geological Construction." Key Engineering Materials 516 (June 2012): 545–50. http://dx.doi.org/10.4028/www.scientific.net/kem.516.545.
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Rotary drilling rigs, general construction equipment, are widely used for deep drilling of ground for the foundations of public works. A new 250kN.m-type rotary drilling rig, most widely used in this field, is under development, and this study focuses on the operational safety of the mast subassembly on the basis of structure analysis of the mast subassembly using a finite element method with ANSYS. When using a drilling rig, an electric rotary drive supplies power for drilling. Here, the elevation of the rotary drive along the mast needs to be changed according to the geological construction environment. Through the analysis, the allowable torques at various elevations of the rotary drive are evaluated, also the safety of the drilling tool called the kelly bar subassembly is examined. Finally, the suitability of the mast subassembly design is examined from the analysis results.
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Lin, Bor-Ren, and Chu-Xian Dai. "Wide Voltage Resonant Converter Using a Variable Winding Turns Ratio." Electronics 9, no. 2 (February 21, 2020): 370. http://dx.doi.org/10.3390/electronics9020370.
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This paper presents a inductor–inductor–capacitor (LLC) resonant converter with variable winding turns to achieve wide voltage operation (100–400 V) and realize soft switching operation over the entire load range. Resonant converters have been developed for consumer power units in computers, power servers, medical equipment, and adaptors due to the advantages of less switching loss and better circuit efficiency. The main disadvantages of the LLC resonant converter are narrow voltage range operation owing to wide switching frequency variation and limited voltage gain. For computer power supplies with hold-up time function, electric vehicle battery chargers, and for power conversion in solar panels, wide input voltage or wide output voltage operation capability is normally demanded for powered electronics. To meet these requirements, the variable winding turns are used in the presented circuit to achieve high- or low-voltage gain when Vin is at low- or high-voltage, respectively. Therefore, the wide voltage operation capability can be implemented in the presented resonant circuit. The variable winding turns are controlled by an alternating current (AC) power switch with two back-to-back metal-oxide-semiconductor field-effect transistors (MOSFETs). A 500-W prototype is implemented and test results are presented to confirm the converter performance.
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Abdali, L. M., V. V. Kuvshinov, E. A. Bekirov, and F. M. Al-Rufaee. "DEVELOPMENT OF THE SIMULATION AND CONTROL SYSTEM FOR AN INTEGRATED SOLAR ENERGY GENERATION AND STORAGE." Construction and industrial safety, no. 18 (70) (2020): 133–42. http://dx.doi.org/10.37279/2413-1873-2020-18-133-142.
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When photovoltaic stations operate, providing large populated areas of the planet, and generating significant amounts of electrical energy, problems often arise due to the inconstancy of the flux of incident solar radiation. This leads to failures in the operation of electrical networks and rapid wear of equipment. By equipping such facilities with new systems for the control and monitoring of photovoltaic parameters, it is possible to significantly increase the generation of electrical energy supplied to the general or local power system, and improve the efficiency of the electrical installations located at the solar power plant. The proposed work presents a general approach to modeling and controlling the operation of photovoltaic systems (PV systems). The necessary data for modeling are provided by manufacturers in the form of tables. The processing of this data provides experimenters and engineers with a convenient way to investigate the problems of integrating photovoltaic systems into uninterruptible generation installations to supply individual consumers. The two-stage power conversion system (PCS) proposed in this article works in conjunction with a photovoltaic generating system. The electrical energy storage system (BESS system) uses rechargeable batteries and can be connected to the DC circuit by means of a bidirectional converter. Thus, the BESS system may provide some auxiliary services that may be needed to improve operational efficiency during the generation process. This article describes a special system of uninterrupted operation (FRT-system), which allows you to create the possibility of uninterrupted operation and the generation of electrical energy by the generation system, in case of incorrect operation of individual nodes (for example, with partial shading of solar modules). The operation of an integrated generation system, an electric energy storage system (BESS-system) and a photovoltaic system (PV-system), together with the corresponding control systems simulated on Matlab platforms and the simulation results confirm the efficiency of the controller. When introducing the proposed systems at existing and under construction solar power plants (SPP), it is possible to significantly improve the efficiency of their work and increase the generation of electricity for consumers.
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Ali, Dr Esmail. "Effect of Magnetic Field From Mobile Phone on Brain." JOURNAL OF ADVANCES IN PHYSICS 10, no. 3 (October 6, 2015): 2784–94. http://dx.doi.org/10.24297/jap.v10i3.1326.
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Human exposure to electromagnetic field (EMF) comes from many different sources and occurs in various situations in everyday life. Man-made static fields are mainly found in occupational settings, such as close to magnetic resonance imaging (MRI) scanners, although DC high-voltage overhead transmission lines are being constructed, which are expected to expose larger parts of the population to static electric and magnetic fields.Today, for power regulation most modern electrical equipment uses electronics instead of transformers. Examples include the switched power supplies to laptops, drilling tools, chargers of mobile phones and similar devices. As a consequence, the frequency content of the daily magnetic field exposure has changed mainly by adding odd harmonics (150 Hz, 250 Hz, 750 Hz, etc.). In particular, the third harmonic (150 Hz) has become another dominating frequency in our environment.In particular for brain tissues, the mobile phone used at the ear remains the main source of exposure. However, since the first generation of mobile telephony, the technology aimed at reducing the emitted power of mobile handsets. In particular, for Global System for Mobile communication (GSM) already the introduction of dynamic power control reduced the average output power to about 50% of its rated value during calls, whereas the use of discontinuous transmission during voice calls gave a further 30% reduction in average emitted power. Adaptive power control became faster and more effective in the third-generation (3G) of mobile telephony systems leading to a further reduction (by about two orders of magnitude) in the specific absorption Specific energy Absorption Rate (SAR) compared to GSM phones. In addition, hands-free kits reduce the energy absorbed by the head drastically. Digital Enhanced Cordless Telecommunications (DECT) phones are another source of everyday exposure.
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Do, Tri Cuong, Hoai Vu Anh Truong, Hoang Vu Dao, Cong Minh Ho, Xuan Dinh To, Tri Dung Dang, and Kyoung Kwan Ahn. "Energy Management Strategy of a PEM Fuel Cell Excavator with a Supercapacitor/Battery Hybrid Power Source." Energies 12, no. 22 (November 15, 2019): 4362. http://dx.doi.org/10.3390/en12224362.
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Construction machines are heavy-duty equipment and a major contributor to the environmental pollution. By using only electric motors instead of an internal combustion engine, the problems of low engine efficiency and air pollution can be solved. This paper proposed a novel energy management strategy for a PEM fuel cell excavator with a supercapacitor/battery hybrid power source. The fuel cell is the main power supply for most of the excavator workload while the battery/supercapacitor is the energy storage device, which supplies additional required power and recovers energy. The whole system model was built in a co-simulation environment, which is a combination of MATLAB/Simulink and AMESim software, where the fuel cell, battery, supercapacitor model, and the energy management algorithm were developed in a Simulink environment while the excavator model was designed in an AMESim environment. In this work, the energy management strategy was designed to concurrently account for power supply performance from the hybrid power sources as well as from fuel cells, and battery lifespan. The control design was proposed to distribute the power demand optimally from the excavator to the hybrid power sources in different working conditions. The simulation results were presented to demonstrate the good performance of the system. The effectiveness of the proposed energy management strategy was validated. Compared with the conventional strategies where the task requirements cannot be achieved or system stability cannot be accomplished, the proposed algorithms perfectly satisfied the working conditions.
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Rahman, M. M. "Analysis and Design of an Air-Cycle Microclimate Cooling Device." Journal of Energy Resources Technology 118, no. 4 (December 1, 1996): 293–99. http://dx.doi.org/10.1115/1.2793876.
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This paper presents an innovative concept of using air-cycle technology for the development of a microclimate cooling device for use by soldiers in the battlefield. The device is an integrated heat engine and heat pump which supplies air at a prescribed temperature and humidity for personal cooling of a soldier wearing protective ensembles, generates electrical energy to power communication equipment, and produces drinking water by condensing atmospheric moisture which may be very useful in desert warfare. It consists of a centrifugal compressor, two turbines or expanders, a combustion chamber, three heat exchangers, a water separator, and an electric generator. Atmospheric air is used as the working fluid in both the engine and cooling loops and diesel is used as the fuel for combustion. A detailed thermodynamic analysis and design optimization was performed. It was found that the system efficiency increases with operating pressure ratio, attains a maximum, and decreases with further increase of pressure ratio. The system efficiency was found to be also dependent on the air-fuel ratio, and the maximum efficiency was found to occur at a specific air-fuel ratio, for any given pressure ratio. The optimum operating condition determined from the thermodynamic analysis was used to outline a detailed design of the system.
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Zapanov, Oleg V., and Lidiia I. Kovernikova. "On the power quality of electrical energy supplied to joint stock company “Aleksandrovsky mine”." E3S Web of Conferences 209 (2020): 07012. http://dx.doi.org/10.1051/e3sconf/202020907012.
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Joint Stock Company (JSC) “Mine Aleksandrovsky” is located in the Mogochinsky district of the Trans-Baikal Territory. “Mine Aleksandrovsky” concluded an energy supply agreement with JSC “Chitaenergosbyt” for the purchase of electric energy from it. In accordance with the contract, the electric energy supplier undertakes to supply electric energy that meets the requirements of the current legislation of the Russian Federation. The power quality in the Trans-Baikal Territory in most regions does not meet the requirements of State Standard 32144-2013. Suppliers and the network organization are responsible to consumers for the reliability of its electric energy supply and its quality within the boundaries of their electric networks. Despite the obligations of the contract, the electric energy supplied to “Mine Alexandrovsky” does not meet the requirements. In 2017 the ball mill engine in the shredding department of the gold recovery factory failed as a result of power outages and the supply of low power quality through the 6 kV line. The article provides information on interruptions in power supply over the years of operation of the enterprise, the results of analysis of the power quality, information on damage to electrical equipment caused by low power quality, and economic damage.
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Ross, D. "Power struggle [power supplies for portable equipment]." IEE Review 49, no. 7 (July 1, 2003): 34–38. http://dx.doi.org/10.1049/ir:20030705.
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Cazacu, Emil, Lucian Petrescu, and Maria-Cătălina Petrescu. "THE MAJOR PREDICTIVE MAINTENANCE ACTIONS OF THE ELECTRIC EQUIPMENTS IN THE INDUSTRIAL FACILITIES." Scientific Bulletin of Electrical Engineering Faculty 18, no. 1 (April 1, 2018): 26–33. http://dx.doi.org/10.1515/sbeef-2017-0018.
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Abstract In modern low-voltage electrical installations, the predictive maintenance of the major electrical equipments involved in the power delivery process (transformers) or in the conversion of the electrical energy (especially electric motors) becomes mandatory. Thus, a high level of reliability and safety is assured for both the electric facility and operators. The proactive maintenance is to be non-invasively performed and mainly requires an infrared (IR) thermographic inspection and power quality analysis of the installation loads. A vibration investigation is also necessary for the motor drive systems. The paper critically studies the first two main maintenance procedures revealing their main characteristics, performances and limits. A case-study presents a 1000 kVA distribution transformer that supplies a bakery facility that comprised mainly heaters and inductions motors as loads.
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Vovk, S., N. Ferents, and A. Lyn. "RELIGIOUS BUILDINGS FIRE SAFETY IN UKRAINE." Fire Safety 37 (January 6, 2021): 24–30. http://dx.doi.org/10.32447/20786662.37.2020.04.
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Problem. Religious buildings with a large number of people are fire hazardous. In total, there are 17,407 religious buildings in Ukraine. Out of them, approximately 3,000 are highly fire hazardous wooden buildings.The fire danger feature of religious buildings is open fire usage: candles, torches, lamps, underground rooms with complex planning, lack of ventilation systems. Besides, ancient religious buildings are mostly built using wooden materials. Fires occuring there are resonant, causing material and spiritual damage to the state and society. On average, about 20 fires occur each year in religious buildings, including wooden temples of historical heritage.Рurpose. Fire analysis in religious buildings in Ukraine and their occurrence causes; fire safety of religious buildings research.Preventive measures for religious building fire safety in Ukraine are prioritised by state program for emergency response. The State Emergency Service of Ukraine constantly monitors compliance with fire safety standards, which includes regular facilities inspections, personnel training control to prevent fires and reduce the consequences of fires, development, implementation, and control of technical methods of safety.Research methods. To achieve this goal, further methods were used: historical, systemic, theoretical generalization, abstract, logical, analysis, synthesis, comparative, and statistical methods.The main results. The most common shortcomings in religious building fire protection are the lack or malfunction of automatic fire alarms, power grid requirement non-compliance with the rules of the power grid, improper facility provision of with primary fire extinguishers, lack of lightning and water supplies for firefighting. In most buildings, wooden structures are not treated with refractory mortar.Fire causes and ways to prevent and improve fire safety are analyzed, namely: fire protection of religious building wooden elements, dome space fire extinguishing systems, fire alarm systems, lightning protection, safe people’s evacuation, candlesticks installation on non-combustible surfaces, primary fire extinguishing equipment, fire condition qualitative inspection of the of the heritage building, etc.Conclusions. After service, buildings must be completely deenergized, lighted candles and open fires must not be left unattended in the church. In religious buildings, it is necessary to carry out fire protection of wooden elements constructions, to install fire extinguishing systems in domed space, fire alarm system, lightning protection, to watch serviceability of electric networks. Rules of fire safety requirements for religious buildings are aimed at solving an important task - religious buildings safety. Unfortunately, due to lack of funds, the most important requirements are not implemented to improve fire safety.
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Vovk, S., N. Ferents, and A. Lyn. "RELIGIOUS BUILDINGS FIRE SAFETY IN UKRAINE." Fire Safety 37 (January 6, 2021): 24–30. http://dx.doi.org/10.32447/20786662.37.2020.04.
Full textAbstract:
Problem. Religious buildings with a large number of people are fire hazardous. In total, there are 17,407 religious buildings in Ukraine. Out of them, approximately 3,000 are highly fire hazardous wooden buildings.The fire danger feature of religious buildings is open fire usage: candles, torches, lamps, underground rooms with complex planning, lack of ventilation systems. Besides, ancient religious buildings are mostly built using wooden materials. Fires occuring there are resonant, causing material and spiritual damage to the state and society. On average, about 20 fires occur each year in religious buildings, including wooden temples of historical heritage.Рurpose. Fire analysis in religious buildings in Ukraine and their occurrence causes; fire safety of religious buildings research.Preventive measures for religious building fire safety in Ukraine are prioritised by state program for emergency response. The State Emergency Service of Ukraine constantly monitors compliance with fire safety standards, which includes regular facilities inspections, personnel training control to prevent fires and reduce the consequences of fires, development, implementation, and control of technical methods of safety.Research methods. To achieve this goal, further methods were used: historical, systemic, theoretical generalization, abstract, logical, analysis, synthesis, comparative, and statistical methods.The main results. The most common shortcomings in religious building fire protection are the lack or malfunction of automatic fire alarms, power grid requirement non-compliance with the rules of the power grid, improper facility provision of with primary fire extinguishers, lack of lightning and water supplies for firefighting. In most buildings, wooden structures are not treated with refractory mortar.Fire causes and ways to prevent and improve fire safety are analyzed, namely: fire protection of religious building wooden elements, dome space fire extinguishing systems, fire alarm systems, lightning protection, safe people’s evacuation, candlesticks installation on non-combustible surfaces, primary fire extinguishing equipment, fire condition qualitative inspection of the of the heritage building, etc.Conclusions. After service, buildings must be completely deenergized, lighted candles and open fires must not be left unattended in the church. In religious buildings, it is necessary to carry out fire protection of wooden elements constructions, to install fire extinguishing systems in domed space, fire alarm system, lightning protection, to watch serviceability of electric networks. Rules of fire safety requirements for religious buildings are aimed at solving an important task - religious buildings safety. Unfortunately, due to lack of funds, the most important requirements are not implemented to improve fire safety.
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Crowder, R., and C. Maxwell. "Simulation of a prototype electrically powered integrated actuator for civil aircraft." Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering 211, no. 6 (June 1, 1997): 381–94. http://dx.doi.org/10.1243/0954410971532749.
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Developments in the design and proposed operation of large civil aircraft have resulted in aircraft manufacturers and equipment suppliers developing new system concepts, one of which is the all or more electric aircraft. In the all or more electric aircraft the distribution of power for flight actuation will be through the electrical system, as opposed to the currently used bulk hydraulic system. In order to implement power-by-wire, high-performance electrically powered actuators will be required. The paper discusses the design details, and the simulation of an electrohydrostatic actuator suitable for use in primary flight control systems of a civil aircraft. The paper presents experimental and simulation results, and identifies the parameters that will critically affect the performance of an actuator.
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Gryz, Krzysztof, and Jolanta Karpowicz. "Stationary computer devices: identification and assessment of the electromagnetic field in the working space." Occupational Safety – Science and Practice 563, no. 8 (August 14, 2018): 21–23. http://dx.doi.org/10.5604/01.3001.0012.2226.
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This article discusses the electromagnetic field emitted by stationary computer devices (personal computers and servers): CRT and LCD screen monitors, system units and peripheral equipment such as wireless communication mice and keyboards, direct current suppliers (AC/DC), uninterruptible power supplies (UPS), and network and electrical supplying cables. Computer devices emit an electromagnetic field from 50 Hz to several GHz. Electromagnetic hazards in the working space near those computer devices do not require individual assessment of the compliance of the level of electromagnetic exposure with the limits provided with respect to the protection of workers against electromagnetic hazards, because the distance between the operator’s body and the equipment is at least 20 cm. This article does not discuss other exposure scenarios such as repairing devices or using portable devices.
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Mikkili, Suresh, and Anup Kumar Panda. "Power Quality Issues and Solutions – Review." International Journal of Emerging Electric Power Systems 16, no. 4 (August 1, 2015): 357–84. http://dx.doi.org/10.1515/ijeeps-2014-0052.
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Abstract Electrical power quality has been an important and growing problem because of the proliferation of nonlinear loads such as power electronic converters in typical power distribution systems in recent years. Particularly, voltage harmonics and power distribution equipment problems result from current harmonics produced by nonlinear loads. The Electronic equipment like, computers, battery chargers, electronic ballasts, variable frequency drives, and switch mode power supplies, generate perilous harmonics and cause enormous economic loss every year. Problems caused by power quality have great adverse economic impact on the utilities and customers. Due to that both power suppliers and power consumers are concerned about the power quality problems and compensation techniques. Power quality has become more and more serious with each passing day. As a result active power filter gains much more attention due to excellent harmonic and reactive power compensation in two-wire (single phase), three-wire (three-phase without neutral), and four-wire (three-phase with neutral) ac power networks with nonlinear loads. However, this is still a technology under development, and many new contributions and new control topologies have been reported in the last few years. It is aimed at providing a broad perspective on the status of APF technology to the researchers and application engineers dealing with power quality issues.
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Плахотникова and E. Plakhotnikova. "Neglect of Differentiation — Loss of Competitive Advantage (Example of Russian Producers of Fittings for NPP)." Economics 2, no. 2 (April 17, 2014): 30–33. http://dx.doi.org/10.12737/3651.
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Purchase of equipment for a nuclear power plant is carried out by Rosenergoatom
concern according to the Federal law No. 223-FZ “About purchases of goods,
works, services by separate types of legal entities” dated 18.07.2011. Among
the main criteria of assessment are quality, supplier’s reliability, delivery time
and price. Considering that in such tenders the reliable suppliers participate
which possess of considerable production potential and capable in tight
deadlines and approximately equal terms to fabricate and supply an equipment,
and that quality criterion is estimated on compliance of technical characteristics
which have been set in tender documentation to characteristics specified in
suppliers’ demands, the basis for decision-making on a contract award is first
of all a price. The price of electro-driving fittings depends on a basic cost of
electric drive and shutoff valves. Through a comparative analysis of electrodriving
shutoff valves of various producers it has been established that in some
cases for management of absolutely identical shutoff valves foreign and
domestic producers use the electric drives of various power. The use of more
powerful electric drive as an actuation device in Russia considerably increases
a system cost and therefore reduces domestic production competitiveness at
tender purchases. The reason of competitiveness decrease is connected with
incorrectness of fittings’ power characteristics calculation techniques which are
used by almost all fittings manufacturers of Russia, and unreasonably
overestimated power system characteristics as a result of unification. Revision
of expediency of the unification accepted still in the last century can reduce
considerably the price of domestic systems of electro-driving shutoff valves and
increase the production’s competitiveness and quality.
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Markova, Evgeniia, and Inna Sidler. "Numerical solution of the age structure optimization problem for basic types of power plants." Yugoslav Journal of Operations Research 29, no. 1 (2019): 81–92. http://dx.doi.org/10.2298/yjor171015009m.
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Our paper addresses an integral model of the large electric power system optimal development. The model takes into account the age structure of the main equipment, which is divided into several types regarding its technical characteristics. This mathematical model is a system of Volterra type integral equations with variable integration limits. The system describes the balance between the given demand for electricity, the commissioning of new equipment and the dismantling of obsolete equipment, as well as the shares of different types of power plants in the total composition of the electric power system equipment. Based on the developed model, we got numerical solution to the problem of finding the optimal strategy for replacing equipment with a minimum of the cost functional. The case study is the Unified Electric Power System of Russia. Calculations of the forecast for development of the electric power system of Russia until 2050 were made using real-life data.
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Wu, Shi Hong, and Xiao Di Xu. "Condition-Based Maintenance and State Diagnosis of Electric Equipment." Advanced Materials Research 706-708 (June 2013): 1994–97. http://dx.doi.org/10.4028/www.scientific.net/amr.706-708.1994.
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Time-based maintenance is mainly used by power plants in our country. Through the study of the disadvantages of time-based maintenance, condition-based maintenance is proposed. This paper details the superiority and the concept of condition-based maintenance, the trigonometry fuzzy number theory and the fuzzy fault tree analysis have been proposed in the state diagnosis. This paper provides the reference to online monitoring and the levels of diagnosis. It’s a reliable plan that the application of condition-based maintenance to power plants.
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JOVANOVIĆ, MILAN M. "SURVEY OF STATE-OF-THE-ART TECHNOLOGIES FOR COMPUTER–NETWORK SERVER AC/DC POWER SUPPLIES." Journal of Circuits, Systems and Computers 13, no. 03 (June 2004): 399–423. http://dx.doi.org/10.1142/s0218126604001659.
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Due to a continuously increasing power demand of computer–network server equipment, power supply manufacturers are faced with requirements for ac/dc server power supplies with significantly higher power densities. In this paper, circuit technologies and optimization techniques that are suitable for meeting these new power-density requirements are discussed. The focus of the paper is on single-phase, single-output ac/dc power supplies that are used to generate a dc-bus voltage in distributed power systems employed in high-end network servers and telecom systems.
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Ahmed, Si Zegnoun, Mohammed Nasser Tandjaoui, Mokhtar Djebbar, Chellali Benachaiba, and B. Mazari. "Power quality enhancement by using D-FACTS systems applied to distributed generation." International Journal of Power Electronics and Drive Systems (IJPEDS) 10, no. 1 (March 1, 2019): 330. http://dx.doi.org/10.11591/ijpeds.v10.i1.pp330-341.
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<p>In the majority of the isolated areas, the diesel generator is the principal source of electric power. For these areas, the price of extension of the electrical supply network is prohibitory and the price of fuel increases radically with insulation. The continuous fall in the prices of the generators based on renewable energy and the increasing reliability of these systems led to a greater use of the sources of renewable energy for the generation of electric power in the isolated areas. The diesel generators can incorporate in a network with other sources in base of renewable energies in order to create a new network known as distributed network. More recently intermittent renewable resources such as the wind power were considered as a distributed generation which is seen as being deployed to reduce the total emissions. The distributed generation equipment sets causing electric disturbances result in destabilizing the global network as well as pollutant, for these reason, system D-FACTS comes to answer all the concern of the customers, manufacturers, suppliers and the managers of the distributed network<em>.</em></p>
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Gemueva, K. A. "Chinese Export to the African Countries: Links with Chinese Energy Projects." Outlines of global transformations: politics, economics, law 14, no. 2 (April 2, 2021): 145–63. http://dx.doi.org/10.23932/2542-0240-2021-14-2-145-163.
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The article examines the relationship between China’s exports to African countries and the implementation of energy projects by Chinese companies. The structure of Chinese exports to Africa and trends in the development of bilateral trade is analyzed. Key factors explaining the close correlation between exports and project implementation are: first, the significant volume of tied financing provided by Chinese banks for the construction of energy infrastructure in African countries, second, the need of these countries to purchase a lot of high-tech equipment in the absence of relevant industries on their territory. The dynamics of supplies of specialized equipment from China used for the construction of various types of power plants - hydroelectric power plants, thermal power plants, wind power plants and solar power plants - is considered in detail. The article provides examples of energy projects of Chinese companies in African countries, for which the supply of equipment is directly found in the imports of the respective countries from China. The tendency for Chinese companies to open production facilities in African countries, in particular cement plants and a photovoltaic modules plant, is noted. The author concludes that the African market remains extremely promising for the implementation of energy projects and the sale of relevant Chinese products despite some negative factors.
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Xie, Hai Jiang, and Wei Li Li. "Application Research of Electrical Automation Technology for Power Plant." Applied Mechanics and Materials 721 (December 2014): 595–98. http://dx.doi.org/10.4028/www.scientific.net/amm.721.595.
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The electrical automation technology is an advanced technology, in power plants, mainly giving play to the role of monitoring, monitoring analysis for the operation condition of the electric, also can have the data signal feedback function. Electrical automation technology is mostly play the function of monitoring, during the running of the electrical equipment, the equipment running status monitoring, through the analysis of the data and feedback, can timely find problems arising from the operation, and warning. In power plants, the use of automation technology also analysis and remote data transmission, realize the online management of equipment, improving the efficiency and quality of power plants. Electrical automation technology applications for the future development of the power plant provide a favorable environment.
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Farhadzadeh, E. M., A. Z. Muradaliyev, Y. Z. Farzaliyev, and U. K. Ashurova. "Internal Benchmarking of Thermal Power Plants оf Electric Power Systems." ENERGETIKA. Proceedings of CIS higher education institutions and power engineering associations 63, no. 6 (December 2, 2020): 541–53. http://dx.doi.org/10.21122/1029-7448-2020-63-6-541-553.
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Improving the operational efficiency (OE) of thermal power plants is one of the most important problems of electric power systems (EPS). According to modern concepts, efficiency is the simultaneous consideration of three properties of objects, viz. economy, reliability and safety. The methodology of their joint assessment assumes that the service life of the main equipment does not exceed the standard value, but this condition is now met by less than half of the production enterprises of a lot of EPS. In order to increase OE, it is necessary, first of all, to learn how to objectively compare the performance of objects both of the same type – in a given time interval, and unique ones – in adjacent intervals. Existing methods for calculating integrated performance indicators do not fully take into account the random nature of technical and economic indicators (TEI). The article presents a new method for comparing the OE of EPS objects, the essence of which is to switch from joint consideration of TEI to analysis of their relative changes in comparison with the factory default value (nominal value). Relative values of indicators characterize the amount of wear or residual life. In this case, for example, the arithmetic mean of the relative values of the TEI determines the average wear of the object. This physical representation enlivens integral indicators, and their comparison and ranking ceases to be science-intensive. It is proposed to take into account also the degree of variation of relative deviations (wear), which is adequate to the object’s misalignment. It manifests itself in a significant change (deterioration) of one or (less often) two relative values of the TEI in the calculated time interval (month) and is characterized by such statistical indicators as the geometric mean and the coefficient of variation of relative deviations. Herewith, if the arithmetic mean value of the object’s wear is restored during major repairs, then the misalignment is eliminated much faster – during current repairs. A necessary condition for the feasibility of using these or those integral indicators is their functional and statistical independence. The results of the studies performed using the simulation method made it possible to establish that the smallest correlation occurs between the integral indicator calculated as the arithmetic mean of random variables and the integral indicator calculated as the coefficient of variation of the same random variables. Comparison of correlation fields clearly confirms these conclusions.
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Leo, Egidio, and Sebastian Engell. "Integrated day-ahead energy procurement and production scheduling." at - Automatisierungstechnik 66, no. 11 (November 27, 2018): 950–63. http://dx.doi.org/10.1515/auto-2018-0016.
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Abstract For the optimal operation of power-intensive plants, a challenge which is addressed in this work is to simultaneously determine the optimal production schedule and the optimal day-ahead electricity commitment. In order to ensure stability of the power grid, the electricity suppliers impose a daily electricity commitment to large consumers. The consumers have to commit one day in advance to the amount of energy they are going to purchase and use for a horizon of 24 hours (with an hourly discretization) and in case the actual electricity consumption differs significantly from the committed profile, the consumer is obliged to pay penalties. Since the consumers have to commit to the electricity suppliers before the actual electricity demand is known, uncertainty needs to be taken into account. A stochastic mixed-integer linear programming model is developed to consider two critical sources of uncertainty: equipment breakdowns and deviation prices. Equipment breakdowns can reduce the production capacity and make the actual electricity consumption deviate from the day-ahead electricity commitment. The application of the proposed approach to a continuous power-intensive plant shows the benefit gained from the solution of the stochastic model instead of the deterministic counterpart in terms of reduction of the cost of the energy.
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Taufik, Taufik, and Afrizal Afrizal. "Evaluasi Kinerja Pemeliharaan PLTA dengan Pendekatan Maintenance Scorecard dan Objective Matrix (OMAX) (Studi Kasus Unit Pembangkit Listrik Tenaga Air Maninjau)." Jurnal Optimasi Sistem Industri 13, no. 1 (April 25, 2016): 562. http://dx.doi.org/10.25077/josi.v13.n1.p562-575.2014.
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Hydropower is one of the power plants that supplies electrical energy. It has several machines and equipment that have a time limit of use. To anticipate the limitation of the use, maintenance of machinery and equipment are needed in order to return its original state and can perform its function as usual. Therefore some indicators required to determine maintenance work performance level to provide the optimal results. The Traditional measurement methods have some limitations that make it difficult to implement in industrial environments. This requires a performance measurement method that can provide a balanced perspective on the overall system performance. One of them is implementing the Maintenance Scorecard and Objective Matrix (OMAX) method to assess the performance of hydropower maintenance. Objective research in this assessment is to integrate Maintenance Scorecard and Objective Matrix (OMAX) approach in Maninjau Hydropower. Key Performance Indicators (KPI) are defined by 6 perspectives: productivity perspective, cost effectiveness perspective, a safety perspective, an environmental perspective, quality perspective and learning perspective. The priorities are determined by using Analytical Hierarchy Process (AHP). We then measure the performance of maintenance by using Objective Matrix (OMAX) until we get the level of achievement of the performance in the current situation.The results obtained in the process of designing the scorecard maintenance on the Maninjau hydropower that produces overall 20 KPI consists of 9 KPI for productivity perspective, 4 KPI for quality perspective, 2 KPI for safety perspective, 2 KPI for environmental perspective and 3 KPIs for learning perspective. There are 5 KPIs for corporate level, 8 KPIs for strategic level and 7 KPIs functional level. The operation results show the number of KWH that produced, Capacity Factor and Equivalent Outage Force Factor are in the yellow zone. It means the attentions and improvements are needed to improve performance in the next period.Keywords: Maintenance Scorecard, Analitycal Hierarchy Process, Objective MatrixAbstractPembangkit Listrik Tenaga Air (PLTA) merupakan salah satu jenis pembangkit listrik. Pembangkit tersebut memiliki serangkaian mesin dan peralatan yang memiliki umur pemakaian tertentu. Sebagai langkah antisipasi terhadap habisnya umur pakai tersebut, diperlukan kegiatan perawatan untuk mengembalikan kondisi mesin dan peralatan sehingga bisa menjalankan fungsinya dengan lancar. Beberapa indikator dibutuhkan untuk menentukan tingkat kinerja aktivitas perawatan agar kegiatan perawatan yang dilakukan dapat memberikan hasil yang optimal. Metode pengukuran tradisional memiliki keterbatasan yang menjadikannya sulit diimplementasikan dalam lingkungan industri. Oleh karena itu dibutuhkan metode pengukuran performansi yang dapat melakukan penilaian dari berbagai perspektif secara seimbang terhadap kinerja sistem secara keseluruhan. Salah satu caranya adalah dengan menerapkan metode Maintenance Scorecard dan Objective Matrix (OMAX) untuk menilai kinerja perawatan PLTA. Tujuan penelitian dalam penilaian ini adalah untuk mengintegrasikan pendekatan Maintenance Scorecard dan OMAX pada PLTA Maninjau. Key Performance Indicators (KPI) didefinisikan dari 6 perspektif: perspektif produktivitas, perspektif efektifitas biaya, perspektif keselamatan kerja, perspektif lingkungan, perspektif kualitas dan perspektif pembelajaran. Prioritas ditentukan menggunakan Analytical Hierarchy Process (AHP). Kinerja perawatan kemudian diukur menggunakan OMAX sampai diperoleh tingkat kinerja pada kondisi nyata. Hasil yang diperoleh kemudian digunakan untuk merancang maintenance scorecard bagi PLTA Maninjau, menghasilkan 20 KPI yang terdiri atas 9 KPI untuk perspektif produktivitas, 4 KPI untuk perspektif kualitas, 2 KPI untuk perspektif keselamatan kerja, 2 KPI untuk perspektif lingkungan dan 3 KPI untuk perspektif pembelajaran. Terdapat 5 KPI untuk level korporat, 8 KPI untuk level strategis dan 7 KPI untuk level fungsional. Hasil penilaian menunjukkan bahwa Jumlah KWH yang diproduksi, Faktor kapasitas dan Equivalent Outage Force Factor berada pada zona kuning. Hal ini berarti bahwa dibutuhkan perhatian dan peningkatan untuk periode selanjutnya.Kata Kunci: Maintenance Scorecard, Analitycal Hierarchy Process, Objective Matrix
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Hraniak, Valerii, Ihor Kupchuk, and Volodymyr Gontar. "METHOD AND DEVICE OF DIRECT AUTOMATED MEASURING CONTROL OF THE INSULATION OF THE WINDING OF ELECTRIC MACHINES." ENGINEERING, ENERGY, TRANSPORT AIC, no. 2(109) (August 27, 2020): 129–37. http://dx.doi.org/10.37128/2520-6168-2020-2-14.
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Today, the vast majority of technological processes, both production and agriculture, are based on the use of electric machines. Among which, a significant part of production equipment requires the use of electric motors, the power of which exceeds hundreds of kilowatts. Such electric machines have also become widespread as generating equipment, where they are an integral part of power plants, both using traditional energy sources (thermal power plants, nuclear power plants, etc.), and renewable (hydroelectric power plants, wind farms, etc.), where the unit power of a single electrical machine is usually higher than in other sectors of economy. When operating such equipment, systems for monitoring a significant number of technological parameters are often used, and in real time it characterizes the modes of their operation. This approach makes it possible to increase the reliability of operation and, with a fairly high probability, to avoid large-scale man-made threats that can be caused by an emergency failure of power electric machines (including powerful electric generators), which are quite often accompanied by the destruction of supporting structures, structural elements of industrial premises and can pose a threat to the life and health of production personnel. But the use of even the most modern systems for monitoring the technical condition does not provide one hundred percent reliability, and when operating electrical machines with a nominal power of the order of units of MW and below, their use can significantly increase the total cost of equipment with a still quite high level of occurrence of a serious man-made accident. Therefore, the development of direct methods and means for measuring the technical parameters of electrical machines in general, and insulation parameters in particular, is an urgent scientific and applied problem. In the article was proposed a new method of direct automated measuring control of insulation of windings of an electric machine, based on the use of combined signals to determine the technical parameters of the insulation of electrical machine units. And also, the design of the measuring control has been developed, it implements the proposed method.
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Krotova, Elena, and Emil Vugar Ogly Sultanov. "Network controller-based remote monitoring and control of power plants over the Internet." Energy Safety and Energy Economy 4 (August 2021): 38–42. http://dx.doi.org/10.18635/2071-2219-2021-4-38-42.
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Internet-based monitoring brings new capabilities and unprecedented access to process power equipment monitoring and control. In this paper, we present an advanced network controller-based remote monitoring and control system for power plants, for example gas engine units. This advanced system processes and displays information, transmits it over the network, and sends control commands to remote equipment. This system is able to help lower cost of electric power generation, improve efficiency and reliability of a power plant and achieve its no-failure operation. We provide the detailed description of necessary equipment and describe all benefits of the mentioned system.
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Held, Lukas, Alexandra Märtz, Dominik Krohn, Jonas Wirth, Martin Zimmerlin, Michael R. Suriyah, Thomas Leibfried, Patrick Jochem, and Wolf Fichtner. "The Influence of Electric Vehicle Charging on Low Voltage Grids with Characteristics Typical for Germany." World Electric Vehicle Journal 10, no. 4 (December 10, 2019): 88. http://dx.doi.org/10.3390/wevj10040088.
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The increasing number of electric vehicles poses new challenges to the power grid. Their charging process stresses the power system, as additional energy has to be supplied, especially during peak load periods. This additional load can result in critical network situations depending on various parameters. These impacts may vary based on market penetration, the energy demand, the plug-in time, the charging rate, and the grid topology and the associated operational equipment. Hence, the impact of electric vehicles (EVs) on the power grid was analysed for twelve typical German low voltage grids by applying power flow calculations. One main result was that thermal and voltage-related network overloads were highly dependent on market penetration and grid topology.