Kliknij ten link, aby zobaczyć inne rodzaje publikacji na ten temat: 25 KV AC.
Artykuły w czasopismach na temat „25 KV AC”
Utwórz poprawne odniesienie w stylach APA, MLA, Chicago, Harvard i wielu innych
Sprawdź 50 najlepszych artykułów w czasopismach naukowych na temat „25 KV AC”.
Przycisk „Dodaj do bibliografii” jest dostępny obok każdej pracy w bibliografii. Użyj go – a my automatycznie utworzymy odniesienie bibliograficzne do wybranej pracy w stylu cytowania, którego potrzebujesz: APA, MLA, Harvard, Chicago, Vancouver itp.
Możesz również pobrać pełny tekst publikacji naukowej w formacie „.pdf” i przeczytać adnotację do pracy online, jeśli odpowiednie parametry są dostępne w metadanych.
Przeglądaj artykuły w czasopismach z różnych dziedzin i twórz odpowiednie bibliografie.
1
Monjo, Lluís, i Luis Sainz. "Study of Resonances in 1 × 25 kV AC Traction Systems". Electric Power Components and Systems 43, nr 15 (5.08.2015): 1771–80. http://dx.doi.org/10.1080/15325008.2015.1048908.
Pełny tekst źródła
2
Zalesova, O. V. "Determination of Electromagnetic Influence of 25 kV AC Electric Traction Network on 10 kV High-Voltage Overhead Line". Journal of Physics: Conference Series 2096, nr 1 (1.11.2021): 012078. http://dx.doi.org/10.1088/1742-6596/2096/1/012078.
Pełny tekst źródłaStreszczenie:
Abstract Electrified railways include a system of cable and overhead lines. An analysis of the operation of alternating current (AC) electrified railways sections shows that the value of the induced voltage caused by the operation of the traction network can significantly exceed the permissible level on adjacent disconnected high-voltage overhead lines. As a consequence, this leads to serious injuries to operating personnel, including deaths, failure of electrical equipment. From this point of view, 1x25 kV 50 Hz AC railway system networks are considered the most dangerous. The electromagnetic influence of the traction network of a double-track section of an AC railway on an adjacent 10 kV high-voltage overhead line for power supply of automatic block signalling is investigated in the offered paper. Emergency cases of traction network operation are considered: short-circuit situation and forced state. The calculations of short-circuit currents in the influencing inter-substation zone, as well as estimation of the induced voltage on the wires of the 10 kV disconnected high-voltage overhead line for various schemes of grounding, have been performed. The investigations were carried out on models built using the ATP-EMTP program.
3
Pawlik, Marek. "Comprehensive approach to risk assessment and evaluation regarding constructioning of the first 25 kV 50 Hz AC traction power supply sections in Poland". MATEC Web of Conferences 180 (2018): 06002. http://dx.doi.org/10.1051/matecconf/201818006002.
Pełny tekst źródłaStreszczenie:
Railway lines in Poland are either equipped with 3 kV DC traction system or not electrified for traction purpose. Presently maximum line speed is 200 km/h while maximum train speed is 250 km/h. Speeding up limit for 3 kV DC traction is estimated to be around 220-230 km/h. Already present in Poland trains for 250 km/h are equipped with three electric power supply systems: 3 kV DC used in Poland, 15 kV 16,7 Hz AC used in Germany, and 25 kV 50 Hz AC foreseen to be used in Poland on high speed lines. Introducing 25 kV 50 Hz AC traction power supply will be associated with safety challenges, which have to be taken into account already during constructioning, starting even at the predesigned phase. Two key questions arise. First of all question regarding methodology, which should be used for safety level acceptance and secondly how to ensure that all safety aspects will be taken into account. Answering first question for railway safety experts seems to be easy – let’s apply risk assessment and evaluation methodology described by EU regulation under Railway Safety Directive. The challenge is however to define risk acceptance criteria which will be required, and that is analysed in the paper. The second challenge is even more challenging. Author proposes using 10-by-10 safety matrix which was defined by the author in previous publications [9, 10]. Its concept as well as principles for its application for new type of power supply is also presented in the paper.
4
Cheung, Henry. "The Immunity of a Signal System under 25 kV AC Traction". HKIE Transactions 13, nr 1 (styczeń 2006): 2–6. http://dx.doi.org/10.1080/1023697x.2006.10668023.
Pełny tekst źródła
5
Bielech, Joanna. "Modelowanie zwarć w układach zasilania trakcji kolejowej 2�25 kV AC". WIADOMOŚCI ELEKTROTECHNICZNE 1, nr 1 (5.01.2019): 27–28. http://dx.doi.org/10.15199/74.2019.1.3.
Pełny tekst źródła
6
Ignatenko, Ivan, Sergey Vlasenko, Evgeniy Tryapkin i Vladimir Kovalev. "Algorithm for calculating the rail-ground potential in heavy load conditions". E3S Web of Conferences 284 (2021): 06002. http://dx.doi.org/10.1051/e3sconf/202128406002.
Pełny tekst źródłaStreszczenie:
Increased freight turnover on railway transport inevitably leads to increased traction current in DC and AC traction power supply systems. The increase in traction current is already causing problems related to the normal operation of the 25 kV AC traction power supply systems. One of the adverse consequences of the increased traction currents is the increased rail-to-ground potential. This has already caused a number of accidents and related traffic interruptions on the Far Eastern Railway of Russia and other railway sections powered with alternating current. The study considers the problem of increased rail-to-ground potentials and provides basic formulae for calculating the wave parameters of the rail network and rail-to-ground potentials. Various methods are given for calculating rail-to-ground potentials for a 25 kV AC traction power supply system. Since in an alternating current system, expressions for calculating the potential are functions of a complex variable, the calculation of such expressions requires the use of special programs. Adaptation of existing methods to modern software and computing systems allows you to optimize and significantly speed up the process of calculating the “rail-to-ground” potentials, either considering the use of certain potential-reducing measures or not. A calculation method includes an algorithm developed for calculating the rail-to-ground potentials in the 25 kV AC traction power supply system for an inter-substation zone of any length with any number of electric locomotives within the zone.
7
Dehcheshmeh, Mehdi Amiri, Seyed Hossein Hosseinian, Mohammad Hossein Bigharaz i Kazem Mohseni. "Analysis of lightning transient in 2 × 25 kV AC autotransformer traction system". International Journal of Power and Energy Conversion 9, nr 1 (2018): 89. http://dx.doi.org/10.1504/ijpec.2018.088268.
Pełny tekst źródła
8
Mohseni, Kazem, Mohammad Hossein Bigharaz, Mehdi Amiri Dehcheshmeh i Seyed Hossein Hosseinian. "Analysis of lightning transient in 2 × 25 kV AC autotransformer traction system". International Journal of Power and Energy Conversion 9, nr 1 (2018): 89. http://dx.doi.org/10.1504/ijpec.2018.10008084.
Pełny tekst źródła
9
Nezevak, V. L. "Comparison of energy parameters of electric storage systems for DC and AC traction power supply systems". Russian Railway Science 81, nr 1 (29.03.2022): 38–52. http://dx.doi.org/10.21780/2223-9731-2022-81-1-38-52.
Pełny tekst źródłaStreszczenie:
Introduction. The article discusses the energy parameters of electric power storage systems for DC and AC traction power supply systems. The purpose of the research is to evaluate the energy parameters of electric power storage systems located within the inter-substation zone boundaries of the AC traction power supply system at the 25 kV voltage.Materials and methods. The author used the methods of modeling, statistics and the experimental results processing. Moreover, the paper presented the parameter estimation of the energy accumulation system on the basis of the traction calculations for the AC rolling stock. In addition, the author made two variants of calculations — in the presence and the absence of the electric storage system. The researcher also made the simulation of the electric storage system for the voltage source connected to the sectioning post busbars.Results. Using the simulation modeling, the author presents active and reactive power graphs of the inter-substation zone boundaries in the active sectioning post operation conditions. Therefore, the article demonstrates the graph of the expected charge, the discharge depth calculations for the nominal energy capacity and the required charging features, which guarantee the charge restoration of the accumulation system to the initial level.Discussion and conclusion. The author offers the comparative assessment of the electric storage systems for the traction power supply with the DС voltage of 3 kV and the AC voltage of 25 kV. The research demonstrates the reducing potential of the nominal accumulation parameters.
10
Konishi, Masayoshi, Teruhisa Nagashima i Yoshinobu Asako. "ER Properties of a Suspension of Polymer Graft Carbon Black Particles". International Journal of Modern Physics B 13, nr 14n16 (30.06.1999): 1682–88. http://dx.doi.org/10.1142/s0217979299001673.
Pełny tekst źródłaStreszczenie:
We newly developed ER particles with sub-micron size. The particle was polymer graft carbon black (GCB1) composed of carbon black particles and a polymer. The average particle size of GCB1 was found to be 81 nm. An ER suspension (ER1) was obtained by mixing GCB1 (30 wt%) with silicone oil (70 wt%). The ER1 showed excellent dispersion stability. Further, GCB1 particles did not settle under centrifuging at 9000G. The zero-field viscosity was 80 mPa·s at 25°C. The kinetic friction coefficient of ER1 was 0.15, while that of the silicone oil used was 0.23. When the electric field of 3 kV/mm (AC 1000 Hz) at the temperature of 25°C and the shear rate of 700 s -1 was applied to ER1, the shear stress of 116Pa was induced. The induced shear stress did not change for a long period of time period. In the temperature range between 25 and 150°C the induced shear stress and the current density were almost constant at any electric field. When 3 kV/mm (AC 50Hz) at 25°C and 700s-1 was applied to ER1, the shear stress of 88Pa was induced but the deviation of the induced shear stress from the average value was pluses and minuses 3 Pa.
11
Seferi, Yljon, Steven M. Blair, Christian Mester i Brian G. Stewart. "Power Quality Measurement and Active Harmonic Power in 25 kV 50 Hz AC Railway Systems". Energies 13, nr 21 (30.10.2020): 5698. http://dx.doi.org/10.3390/en13215698.
Pełny tekst źródłaStreszczenie:
Railway electrical networks rated at 25 kV 50 Hz are characterised by significant levels of voltage and current harmonics. These frequency components are also time varying in nature due to the movement of trains and changing operational modes. Processing techniques used to evaluate harmonic results, although standardised, are not explicitly designed for railway applications, and the smoothing effect that the standard aggregation algorithms have on the measured results is significant. This paper analyses the application accuracy of standardised power quality (PQ) measurement algorithms, when used to measure and evaluate harmonics in railway electrical networks. A shorter aggregation time interval is proposed for railway power quality measurement instruments, which offers more accurate estimated results and improved tracking of time varying phenomena. Harmonic active power present in railway electrical networks is also evaluated in order to quantify the impact it has on the energy accumulated by electrical energy meters installed on-board trains. Analysis performed on 12 train journeys shows significant levels of non-fundamental active power developed for short periods of time. As an energy meter will inadvertently absorb the financial cost of non-fundamental energy produced by other trains or other external power flows, results are provided to support recommendations for future standards to measure only fundamental frequency energy within train energy measurement meters.
12
Mesbahi, Nadhir, Lluis Monjo i Luis Sainz. "Study of Resonances in 1 $\times$ 25 kV AC Traction Systems With External Balancing Equipment". IEEE Transactions on Power Delivery 31, nr 5 (październik 2016): 2096–104. http://dx.doi.org/10.1109/tpwrd.2015.2504548.
Pełny tekst źródła
13
Park, Haneol, Joongho Song i WadaM Hosny. "Comparative study on the position of shunt active power filters in 25 kV AC railway systems". IETE Technical Review 29, nr 5 (2012): 421. http://dx.doi.org/10.4103/0256-4602.103176.
Pełny tekst źródła
14
Plastun, Anatoly, Yuri Neugodnikov i Evgeny Klochikhin. "Approach to Design of Power Transformers for Railway Traction Power Supply System of 25 kV AC". Известия высших учебных заведений. Электромеханика 62, nr 2 (2019): 14–20. http://dx.doi.org/10.17213/0136-3360-2019-2-14-20.
Pełny tekst źródła
15
C., Ravi kumaran Nair, Devender Kumar Saini i Jayaraju M. "Modelling the Dynamic Line Parameter of 25 kV AC Railway Electric Traction Lines at Earth Cuttings". International Journal of Engineering and Technology 8, nr 5 (31.10.2016): 2070–75. http://dx.doi.org/10.21817/ijet/2016/v8i5/160805425.
Pełny tekst źródła
16
Song, Wenjuan, Zhenan Jiang, Mike Staines, Stuart Wimbush, Rodney Badcock i Jin Fang. "AC Loss Calculation on a 6.5 MVA/25 kV HTS Traction Transformer With Hybrid Winding Structure". IEEE Transactions on Applied Superconductivity 30, nr 4 (czerwiec 2020): 1–5. http://dx.doi.org/10.1109/tasc.2020.2975771.
Pełny tekst źródła
17
Manakov, Aleksandr, i Abdulaziz Rahmonberdiev. "Hazardous Electromagnetic Impact of AC 25 kV Reverse Traction Network on Railway Automation and Remote control Devices". Transport automation research 8, nr 3 (13.09.2022): 233–51. http://dx.doi.org/10.20295/2412-9186-2022-8-03-233-251.
Pełny tekst źródłaStreszczenie:
During electric traction of trains, railway automation and Remote control devices, connected to rails or located in close proximity to reverse traction rail network, are affected by overvoltages and overcurrents during emergency processes in a traction network. To develop, basing on mathematical models, of means and systems for protection against overvoltages and overcurrents it is required to work out a model of hazardous electromagnetic impact source at different distances from short circuit spot to traction substation and under various operating conditions. In the article, it has been developed based on state variables method a distributed mathematical model of AC traction network with 25 kV voltage. After computer experiments, it is proposed the replacement of substituion complex scheme for a traction network with equivalent parameters for each half-wave of short-circuit current. Verification has been pursued for the proposed traction network model.
18
Suraidin, S., i Muhammad Nur. "KAJIAN EKSPERIMENTAL EFISIENSI DAN KARAKTERISTIK PRODUKSI OZON BERDASARKAN VARIASI PANJANG DAN LAJU ALIR REAKTOR DIELECTRIC BARRIER DISCHARGE PLASMA (DBDP) BERBAHAN BAJA ANTI KARAT". Jurnal Penelitian Fisika dan Aplikasinya (JPFA) 6, nr 1 (8.06.2016): 18. http://dx.doi.org/10.26740/jpfa.v6n1.p18-25.
Pełny tekst źródłaStreszczenie:
Penelitian ini membahas kajian reaktor ozon dengan dielectric barrier discharge plasma (DBDP): variasi panjang elektroda stainless steel. Konsentrasi ozon dihasilkan dengan melakukan variasi tegangan mulai dari 3-5 kV dan variasi laju alir dari 2, 3, 4, 5, 6, 8, sampai 10 L/menit. Reaktor ozon yang digunakan sebagai pembangkit ozon mempunyai konfigurasi kerangka silinder-silinder. Elektroda dalam (kerangka silinder) terbuat dari stainless stell, sedangkan elektroda luar (silinder) terbuat dari lempengan seng dan bahan dielektrik yang digunakan adalah pyrex. Reaktor diberi tegangan tinggi AC dengan frekuensi 16 kHz. Penelitian ini menggunakan lima variasi panjang reaktor ozon yaitu 5, 10, 15, 20, dan 25 cm. Untuk menentukan konsentrasi ozon pada setiap reaktor yang berbeda, maka ozon yang dihasilkan diserap dalam larutan KI selanjutnya dititrasi dengan natrium thiosulfat. Hasil penelitian menunjukan bahwa semakin panjang elektroda yang digunakan maka konsentrasi ozon yang dihasilkan semakin tinggi, yakni mulai dari 384 sampai dengan 634 ppm untuk laju alir 2 L/menit, sedangkan semakin besar laju alir gas oksigen maka konsetrasi yang dihasilkan semakin kecil, yakni mulai dari 624 sampai dengan 134.4 ppm untuk panjang reaktor 25 cm. Selain itu, semakin tinggi tegangan yang diberikan maka konsentrasi ozon akan semakin meningkat, yakni dengan tegangan 3 sampai 5 kV menghasilkan konsentrasi dari 480 sampai dengan 624 ppm.
19
Farnesi, Stefano, Mario Marchesoni, Massimiliano Passalacqua i Luis Vaccaro. "Solid-State Transformers in Locomotives Fed through AC Lines: A Review and Future Developments". Energies 12, nr 24 (10.12.2019): 4711. http://dx.doi.org/10.3390/en12244711.
Pełny tekst źródłaStreszczenie:
One of the most important innovation expectation in railway electrical equipment is the replacement of the on-board transformer with a high power converter. Since the transformer operates at line-frequency (i.e., 50 Hz or 16 2/3 Hz), it represents a critical component from weight point of view and, moreover, it is characterized by quite poor efficiency. High power converters for this application are characterized by a medium frequency inductive coupling and are commonly referred as Power Electronic Transformers (PET), Medium Frequency Topologies or Solid-State Transformers (SST). Many studies were carried out and various prototypes were realized until now, however, the realization of such a system has some difficulties, mainly related to the high input voltage (i.e., 25 kV for 50 Hz lines and 15 kV for 16 2/3 Hz lines) and the limited performance of available power electronic switches. The aim of this study is to present a survey on the main solutions proposed in the technical literature and, analyzing pros and cons of these studies, to introduce new possible circuit topologies for this application.
20
Kosarev, A. B., A. V. Barch i E. N. Rozenberg. "Ensuring electrical safety of power supply systems of electrified AC railways for highspeed lines". Vestnik of the Railway Research Institute 77, nr 6 (30.12.2018): 337–46. http://dx.doi.org/10.21780/2223-9731-2018-77-6-337-346.
Pełny tekst źródłaStreszczenie:
Abstract. High-speed railways are fast-growing and promising type of traffic. In Russia development of high-speed railway service is associated with the solution of a number of problems, including infrastructure. Authors propose to use earth connection of the railway catenary with the help of an artificial earthing switch on currently designed high-speed line Moscow—Kazan for 2×25 kV power supply system. Taking into account requirements for electrical safety conditions for maintenance of the track and earthed catenary supports, paper justifies method for calculating allowable voltages of rail—earth points and supports of catenary. Methods takes into account structural features of ballastless track superstructure used for high-speed lines. It is estimated that the voltages admissible under the electrical safety conditions are random in nature and distributed logarithmically normal. When calculating probability of safe operation, one should take into account random nature of both permissible stresses and those actually occurring on the track. It is estimated that the probability of safe operation in traction networks of sections with ballastless track superstructure does not exceed a similar value in electrified sections with the conventional structure of a ballast prism. Feasibility of using a 2×25 kV earth system using an artificial earth connection is confirmed, recommendations on its use are given. Authors substantiate allowable values of the rail—earth voltage and catenary supports, which practically exclude the occurrence of hazardous situations for personnel maintaining the track in sections with ballastless track superstructure.
21
Letizia, Palma, Davide Signorino i Gabriella Crotti. "Impact of DC Transient Disturbances on Harmonic Performance of Voltage Transformers for AC Railway Applications". Sensors 22, nr 6 (15.03.2022): 2270. http://dx.doi.org/10.3390/s22062270.
Pełny tekst źródłaStreszczenie:
This paper analyzes the impact of typical DC transient events occurring in railway grids on the frequency performance of instrument transformers (ITs) installed onboard trains and in AC substations for power quality (PQ) applications. PQ monitoring in railway systems is an issue of great interest because it plays a key role in the improvement of energy efficiency. The measurement chain for the PQ measurements, at 15 kV at 16.7 Hz and 25 kV at 50/60 Hz, commonly includes ITs to scale the voltage to levels fitting the input of the measurement units. Nevertheless, the behavior of ITs in the presence of PQ phenomena represents an open issue from a normative point of view, even for those installed in conventional AC power supply systems. In this context, the paper presents a possible definition of DC transient disturbances test waveforms, a measurement procedure, and a setup to assess the impact of these disturbances on the harmonic performances of ITs for railway systems. Preliminary experimental tests carried out on two commercial ITs under wide ranges of variation for the amplitude and the time duration of DC disturbances show that, in some cases, the error introduced in harmonic measurements can exceed 100%.
22
Park, Soo-Cheol, Joong-Ho Song i Sang-Hoon Chang. "Application of Multi-Level Inverter for Improvement of Power Quality in AC 25[kV] Electrified Railway System". Journal of the Korean Institute of Illuminating and Electrical Installation Engineers 21, nr 1 (31.01.2007): 131–41. http://dx.doi.org/10.5207/jieie.2007.21.1.131.
Pełny tekst źródła
23
Shafighy, Mehran, Sui Yang Khoo i Abbas Z. Kouzani. "Modified DSC Propulsion Systems for Efficient Direct Recovery of Regeneration in 25-kV AC Traction Power Supply". IEEE Transactions on Transportation Electrification 3, nr 3 (wrzesień 2017): 632–45. http://dx.doi.org/10.1109/tte.2017.2675627.
Pełny tekst źródła
24
Kus, Vaclav, Bohumil Skala i Pavel Drabek. "Complex Design Method of Filtration Station Considering Harmonic Components". Energies 14, nr 18 (16.09.2021): 5872. http://dx.doi.org/10.3390/en14185872.
Pełny tekst źródłaStreszczenie:
The paper deals with a new methodology for calculating the filter parameters. The basis is respect for the fact that the real filter current consists of other harmonic components, which filter is tuned. The proposed methodology was used to design filters for traction substation 25 kV/50 Hz. The operation of the locomotives in the AC supply systems of 25 kV/50 Hz leads to a rising of higher order harmonic currents. Due to the 1-phase supply system, these are mainly the 3rd and 5th harmonics. By simulation and subsequent measurement of the proposed traction power station filters the proposed methodology was verified. Thus, the filter design can also be used for filter compensating stations of the standard 3-phase distribution network. The described method presents an optimal filter design without unnecessary oversizing. This fact reduces the size and cost of the filter. It is shown that it is possible to design a filter that meets the requirements for power quality under extreme load and to minimise distortion of line voltage.
25
Istrate, Daniela, Abderrahim Khamlichi, Soureche Soccalingame, Jorge Rovira, Dominique Fortune, Martin Sira, Pascual Simon i Fernando Garnacho. "Laboratory Calibration of Energy Measurement Systems (EMS) under AC Distorted Waveforms". Sensors 20, nr 21 (5.11.2020): 6301. http://dx.doi.org/10.3390/s20216301.
Pełny tekst źródłaStreszczenie:
Current standard EN 50463-2 indicates the tests and the requirements to be satisfied for an energy measurement system of a traction unit for railway applications. Some of these tests are to be done with several harmonics superposed on the rated voltage, respectively current. However, no calibration systems satisfying the standard requirements were available few years ago. The work performed in the EURAMET project “MyRailS” leads to the development of fictive power sources and reference measurement systems described in this paper. Therefore, it is possible to generate distorted 25 kV-50 Hz voltages with harmonics up to 5 kHz and 90° phase-fired currents up to 500 A with harmonics up to 5 kHz. The generated power is measured by developed traceable reference systems with accuracy better than 0.5%.
26
Shing, A. W. C., i P. P. L. Wong. "Wear of pantograph collector strips". Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit 222, nr 2 (1.03.2008): 169–76. http://dx.doi.org/10.1243/09544097jrrt156.
Pełny tekst źródłaStreszczenie:
The overhead conductor system (OCS) could be one of the most economical and feasible engineering solutions to the problem of how to transmit electrical energy to intercity trains (typically at 25 kV AC) or urban/suburban trains (typically at 1.5 kV DC) along open or tunnel routes. However, the consumption of contact wire and collector strips due to wear and tear could impose a severe cost on the railway operator should the interaction between the wear couple formed by the OCS and the pantograph be poor. Following the completion of several OCS improvement projects, this paper examines the factors that might have led to higher than expected consumption of collector strips by analysing statistical data from an operational railway. The observations so far are that irregular contact wire height relative to the rails and high ambient humidity have been identified as two of the many factors that led to the abnormal consumption of collector strips.
27
Mustofah NST, Mhd Ai, Hermawan Hermawan, i Denis Denis. "RANCANG BANGUN MINIATUR SISTEM TRANSMISI DAYA ARUS SEARAH DENGAN RECTIFIER SATU FASA, BOOST CONVERTER DAN SISTEM MONITORING MENGGUNAKAN DATA LOGGER BERBASIS MIKROKONTROLER STM32F103C8T6". Transient: Jurnal Ilmiah Teknik Elektro 9, nr 2 (9.06.2020): 261–68. http://dx.doi.org/10.14710/transient.v9i2.261-268.
Pełny tekst źródłaStreszczenie:
High Voltage Direct Current Transmission (HVDC) adalah teknologi pengiriman daya listrik tegangan tinggi (puluhan sampai ratusan kV) dalam bentuk arus searah. Penggunaan arus searah pada saluran transmisi dapat mengurangi rugi-rugi yang disebabkan adanya reaktansi pada saluran. Jatuh tegangan yang dihasilkan lebih kecil sehingga kapasitas daya kirim dapat maksimal. Prinsip dasar teknologi ini adalah pengubahan sumber arus bolak-balik (AC) menjadi arus searah (DC) kemudian ditransmisikan melalui saluran transmisi lalu diubah kembali menjadi arus AC. Pada tugas akhir ini proses pengubahan sumber AC menjadi DC menggunakan rectifier satu phasa gelombang penuh tak terkontrol dengan menggunakan 4 buah dioda IN5409, dan untuk menaikkan tegangan DC pada saluran transmisi menggunakan DC-DC Chopper tipe boost converter dengan menggunakan MOSFET IRF460 yang dilengkapi dengan sistem umpan balik tegangan dan kemudian disalurkan melalui saluran transmisi. Rangkaian sistem tugas akhir ini juga dilengkapi dengan sistem monitoring secara real time yang terhubung dengan internet of things (IOT) ke Thingspeak dengan pembacaan sensor pada awal dan akhir saluran transmisi. Boost converter dirancang dengan variasi panjang saluran dan variasi beban berupa lampu pijar dengan daya 25 watt, 40watt, 60 watt, dan 100 watt untuk mengetahui kinerja boost converter terhadap beban.
28
Asanov, Ibragim, Elizaveta Sharaborova i Egor Loktionov. "Evaluation of technical and economic effect from setup of distributed photovoltaic generation on the Right-of-Way land of the North Caucasus Railway". E3S Web of Conferences 114 (2019): 05004. http://dx.doi.org/10.1051/e3sconf/201911405004.
Pełny tekst źródłaStreszczenie:
In this work, we consider the concept of using a distributed solar power plant, setup on the right-of-way of the railroad. The proposed solution allows to shave peaks of electricity consumption without additional land alienation, using the existing power grids. The concept includes the setup of solar panels on the alienated land of the railroad. PV can be placed directly on the cross ties using damping elements, on the embankment slopes and on the right-of-way land. This solution allows minimizing the cost of solar panels installation along the railway tracks. The North Caucasus railway was considered to assess the gross, technical and economic potential of the proposed solution. The operational length of the railroad there is 6,472 km. The railway consists of large non-electrified sections, segments powered with 25 kV AC and 3 kV DC. The railroad is used not only for cargo transport, but also for long-distance and suburban passenger traffic. We have considered different scenarios for right-of-way land use rate and have shown that possible project costs could be reduced by ca. 25% by double land use only. This does not include shared electric grid infrastructure use that also should benefit considerably, but is hard to be estimated. While the potential nameplate capacity of such power plants within one region is 10s-100s of MW.
29
Agunov, Aleksandr, Anatoliy Burkov i Mihail Ivanov. "Model for Joint Operation of Traction and External Power Supply System". Bulletin of scientific research results 2022, nr 3 (22.09.2022): 24–38. http://dx.doi.org/10.20295/2223-9987-2022-3-24-38.
Pełny tekst źródłaStreszczenie:
Purpose: To improve record accuracy of external power supply network influence on the operation of traction power supply systems of industrial frequency AC. The article shows that existing mathematical models of traction and external power supply joint operation have sounding limitations. These limitations almost exclude the possibility of their practical use. At the same time, when projecting a new electrification, it is required to choose the most efficient external power supply scheme. At the exploitation of existing electrified sections, the necessity arises to assess equalizing current value during repairs in external power supply networks and to adopt a decision on changing power supply and sectioning schemes. Corresponding model is required to solve these tasks. Methods: Analysis of existing mathematical models and computer programs for joint calculation for traction and external power supply networks. Development of three-phase PU-generator models on the basis of EMF source behind an inductive resistance, development of three-phase and single-phase load models. Results: The article presents a description of a mathematical model implied to study the joint operation of 25 kV AC traction power supply systems and 110-750 kV power supply systems. The principles of building the model of three-phase and single-phase PU-generators on EMF source basis behind inductive resistance as well as the models of three-phase and single-phase loads are considered. Based on the given mathematical expressions, a computer model has been developed that allows analyzing the joint operation of three-phase external power supply networks and single-phase traction ones. The model is implemented in MATLAB-Simulink software package. Using this computer model, the influence of power flows through 110–330 kV network of Karelenergo and “FSK EAS” Public Companies on equalizing currents in the traction network of Knyazhaya — Idel section of Oktyabrskaya railway was analyzed. Practical importance: The reliability raise for traction power supply system operation at the expense of precise calculation of equalizing currents. Energy loss reduction in a traction network in account of traction network optimal power supply scheme choice.
30
Dubravin, Y., i V. Tkachenko. "RESEARCH ON THE MODEL OF ASYNCHRONOUS TRACTION ENGINE OF THE AC ELECTRIC LOCOMOTIVE". Collection of scientific works of the State University of Infrastructure and Technologies series "Transport Systems and Technologies", nr 39 (30.06.2022): 175–89. http://dx.doi.org/10.32703/2617-9040-2022-39-17.
Pełny tekst źródłaStreszczenie:
Promising electromotive rolling stock is based on application of asynchronous traction engines with a short-circuited rotor. The use of asynchronous traction motor controller allows: increase power, tractive force and speed of electromotive rolling stock, promote reliability and bring down the cost of life cycle, increase lifetime. In addition to this asynchronous traction motor controller of double power gives an opportunity to provide train traffic through the areas of direct current with a voltage of 3 kV as well as on the areas of alternating current with voltage of 25 kV at a frequency of 50 Hz without replacement of electromotive rolling stock. In the article the mathematical model of asynchronous traction engine is considered taking into account electric and mechanical part of traction motor controller. A model describes electromagnetic processes in stator windings in the fixed α, β, γ coordinate system, which has its axis combined with the axis of stator phases A, B, C. Processes in a shortcircuited rotor are described in the rotating a, b, c coordinate system. For the modeling of mechanical part of motor controller basic equation of dynamics, that characterizes ratio between an electromagnetic torque and section modulus in the shaft of the electric motor, is used. In a proposed model simulation and structural modeling methods were implemented by means of function modules of the Simulink library. A model allows to investigate transition processes given: nonsinusoidal and asymmetric supply voltage; saturation of the magnetic system; current crowding out effect in the rotor conductors; presences of shortings between the turns of the stator winding and damages of rotor rods. A mathematical model is implemented as matrix Simulink model of asynchronous engine in MatLab. Credibility of the mathematical model was checked up while conducting virtual researches of electromechanics characteristics of asynchronous engine of type AD914.The outcome confirmed the adequacy of the implemented model and the possibility of the implemented model to be used in other applications.
31
Golubitskaya, E. A., O. S. Troitskaya, E. V. Yelak, P. P. Gugin, V. A. Richter, I. V. Schweigert, D. E. Zakrevsky i O. A. Koval. "Cold Physical Plasma Decreases the Viability of Lung Adenocarcinoma Cells". Acta Naturae 11, nr 3 (15.09.2019): 16–19. http://dx.doi.org/10.32607/20758251-2019-11-3-16-19.
Pełny tekst źródłaStreszczenie:
The high mortality rate that accompanies cancer spurs the search for new methods that can be used to treat malignant neoplasms. In addition to chemotherapy, electrophysical techniques for tumor treatment appear rather promising. The results of in vitro exposure of A549 human lung adenocarcinoma cells to cold atmospheric plasma (CAP) are hereby presented. A gas-discharge device that generates a sequence of streamers propagating along a stream of inert gas in the ambient air was used. In the zone where the plasma jet came into contact with the target object, there were high-intensity electric fields and high plasma concentrations, while the gas temperature changed by less than a degree. In this study, we compared the cytotoxic effect of CAP in helium and argon. Direct irradiation of cells by CAP with U = 4.2 kV for 30-120 s was shown to reduce cell viability by 25%. Variation of the amplitude of the AC voltage in the plasma device in argon within a range of 3.8-5.6 kV did not significantly alter the cell death rate. Further optimization of the modes of CAP generation in gas-discharge devices with various geometries for the treatment of a tumor cell and animal tumor models can underlie the development of antitumor plasma medicine.
32
Żurkowski, Andrzej. "Traction power consumption as a component of maximum speed choice on High Speed Lines". MATEC Web of Conferences 180 (2018): 01009. http://dx.doi.org/10.1051/matecconf/201818001009.
Pełny tekst źródłaStreszczenie:
The paper includes briefly the most important methodological considerations for selecting the maximum speed for the newly designed HSL. They provide a context for discussion on energy aspects regarding traction energy costs. The research problem in question includes both the assessment of the absolute values associated with the consumption of traction energy and their reference to other costs and revenues associated with the operation of the High Speed Rail (HSR). The proposed approach is based on an analysis of the experience described in the international literature of the subject and simulation calculations for Polish conditions. Based on the approximate results and dependences in this field obtained by the railways with operational experience in relation to the typical HSR train sets, the records of dependencies which are most likely to be confirmed in Polish conditions are presented. Currently, 3 kV DC is used on the railway network in Poland. This is therefore technically different from the one designed on HSL (25 kV AC), which the calculations are related to. Choosing the maximum speed for HSL must take into account the consumption of electricity because of its significant cost. However, the shortening of travel time by increasing the speed makes the HSR offer more attractive and thus allows for increased revenues. The final decision should therefore be a compromise based on detailed calculations, forecasts and simulations.
33
Krylov, A. A., I. A. Rebrov, A. V. Rudashevskaya, R. A. Rudashevskiy i E. D. Khar'kovskaya. "Transition resistance influence of the upper structure track ballast on the rail-to-earth potential at AC railway sections". Russian Railway Science 81, nr 1 (29.03.2022): 16–22. http://dx.doi.org/10.21780/2223-9731-2022-81-1-16-22.
Pełny tekst źródłaStreszczenie:
Introduction. The purpose of the research is to evaluate transition resistance modifications of the upper structure track in passing from the ballast to the ballastless track. These modifications effect the rail-to-earth potential difference. Moreover, they refer to the reverse traction system, to the reverse traction current of railway automation devices and to the required level of electrical safety guarantee.Materials and methods. The authors used both the analytical method of the rail-to-earth potential testing and the practical one based on experimental studies of the rail track transition resistance measurements. The authors carried out experiments on the Rozengartovka — Boitsovo — Bikin section of the Far Eastern Railway. This section includes the heavy freight traffic with the increased electric resistance of the track ballast by the upper structure redevelopment.Results. The research defines the main criteria of the rail-to-earth potential considering the 2×25 and 25 kV reverse traction of monophase AC systems with the 50 Hz frequency and depending on the experimental area location in terms of traction substations, on the climate and geological factors and on the freight traffic density.Discussion and conclusion. The obtained results will improve the accuracy of the rail-to-earth potential difference considering not only indicated factors, but also the upper structure type, track features and a feed line scheme for contact wire.
34
Feltrin, C., A. S. Lima, M. Monaco, S. M. Wilson, D. Kim, M. B. Wheeler i J. L. Rodrigues. "29 EVALUATION OF DIFFERENT FUSION PARAMETERS IN THE RECONSTRUCTION OF SWINE HANDMADE CLONING EMBRYOS". Reproduction, Fertility and Development 20, nr 1 (2008): 95. http://dx.doi.org/10.1071/rdv20n1ab29.
Pełny tekst źródłaStreszczenie:
The goal of this experiment was to compare different fusion parameters in the handmade cloning technique to produce cloned swine embryos. After in vitro maturation of 618 oocytes, 431 (69.8%) presented a visible polar body and were used in the experiment. The next step was the removal of the cumulus oophorus cells and the digestion of the zona pellucida using pronase (5 mg mL–1) in HEPES TCM199. Oocytes were then exposed to a medium containing cytochalasin B (5 µg mL–1) for 15 min before being bisected with a hand-held blade. The bisected oocytes (cytoplasts) were then placed in medium supplemented with Hoechst 33342 and exposed to UV light to select cytoplasts without metaphase II plates. Next, two cytoplasts and a mesenchymal stem cell (nucleus donor) were pushed together in a phytohemagglutinin (550 µg mL–1) solution. Once adhered, these structures were divided into 3 groups (G) to be fused using different parameters: (G1) 2 pulses (DC) of 0.6 kV cm–1 for 30 µs, (G2) 2 pulses (DC) of 0.9 kV cm–1 for 30 µs, and (G3) 2 pulses (DC) of 1.2 kV cm–1 for 30 µs. For all three groups, 0.3 m of mannitol solution (without calcium) was used in the fusion chamber, and an initial pre-pulse (AC) of 10V for 15 s was performed to permit the alignment of 100% of the cytoplast-donor cell structures. After fusion, reconstructed embryos were activated in 0.3 m mannitol and 0.1 mm calcium in the fusion chamber using 2 pulses of 0.9 kV cm–1 for 30 µs followed by incubation in 10 µg mL–1 of cycloheximide solution for 4 h. Afterwards, the reconstructed embryos were transferred to NCSU23 medium supplemented with amino acids (nonessential and essential) and 0.4% bovine serum albumin. The embryos were cultured at 39�C in a 100% humidified atmosphere containing 5% CO2, 5% O2, and 90% N2. Cleavage rates were evaluated after 48 h of culture. For G1, the fusion rate was 43% (25/58) with 72% cleavage (18/25), the G2 fusion rate was 87% (56/64) with 80% cleavage (45/56), and the G3 fusion rate was 79% (53/67) with 69% cleavage (37/53). Statistical analysis was performed using the chi-square test. There were no significant differences in fusion rates between groups G2 and G3, but the fusion rate of these groups was significantly different from that of G1 (P < 0.05). No significant differences in cleavage rate were observed among the three groups. In conclusion, fusion using 2 pulses at either 0.9 or 1.2 kV cm–1 for 30 µs was more efficient for embryo reconstruction in the handmade cloning technique compared to that using 2 pulses at 0.6 kV cm–1 for 30 µs. Further studies need to be performed to improve cleavage rates and assess development to the blastocyst stage.
35
Huber, Jonas E. "Analysis and Cell-Level Experimental Verification of a 25 kW All-SiC Isolated Front End 6.6 kV/400 V AC-DC Solid-State Transformer". CPSS Transactions on Power Electronics and Applications 2, nr 2 (czerwiec 2017): 140–48. http://dx.doi.org/10.24295/cpsstpea.2017.00014.
Pełny tekst źródła
36
Khamlichi, Abderrahim, Fernando Garnacho, Pascual Simon, Jorge Rovira i Angel Ramirez. "Calibration of On-Board Energy Measurement Systems Installed in Locomotives for AC Distorted Current and High Voltage Waveforms and Determination of Its Uncertainty Budget". Sensors 21, nr 23 (29.11.2021): 7967. http://dx.doi.org/10.3390/s21237967.
Pełny tekst źródłaStreszczenie:
Periodic calibrations of Energy Measurement Systems (EMS) installed in locomotives must be carried out to demonstrate the required accuracy established in the EN 50463-2 standard according to European Parliament and Council Directive 2008/57/EC on the interoperability of rail systems within the Community. As a result of the work performed in the “MyRailS” EURAMET project an AC calibration facility was developed consisting of a fictive power source was developed. This fictive power source can generate distorted sinusoidal voltages up to 25 kV-50 Hz and 15 kV-16.7 Hz as well as distorted sinusoidal currents up to 500 A with harmonic content up to 5 kHz or phase-fired current waveform stated in EN50463-2 standard. These waveforms are representative of those that appear during periods of acceleration and breaking of the train. Reference measuring systems have been designed and built consisting of high voltage and high current transducers adapted to multimeters, which function as digital recorders to acquire synchronized voltage and current signals. An approved procedure has been developed and an in-depth uncertainty analysis has been performed to achieve a set of uncertainty formulas considering the influence parameters. Different influence parameters have been analyzed to evaluate uncertainty contributions for each quantity to be measured: rms voltage, rms current, active power, apparent power and non-active power of distorted voltage and current waveforms. The resulting calculated global expanded uncertainty for the developed Energy Measuring Function calibration set up has been better than 0.5% for distorted waveforms. This paper is focused on presenting the complete set of expressions and formulas developed for the different influence parameters, necessary for uncertainty budget calculation of an Energy Measuring Function calibration.
37
Cunillera, Alejandro, Adrián Fernández-Rodríguez, Asunción P. Cucala, Antonio Fernández-Cardador i Maria Carmen Falvo. "Assessment of the Worthwhileness of Efficient Driving in Railway Systems with High-Receptivity Power Supplies". Energies 13, nr 7 (10.04.2020): 1836. http://dx.doi.org/10.3390/en13071836.
Pełny tekst źródłaStreszczenie:
Eco-driving is one of the most important strategies for significantly reducing the energy consumption of railways with low investments. It consists of designing a way of driving a train to fulfil a target running time, consuming the minimum amount of energy. Most eco-driving energy savings come from the substitution of some braking periods with coasting periods. Nowadays, modern trains can use regenerative braking to recover the kinetic energy during deceleration phases. Therefore, if the receptivity of the railway system to regenerate energy is high, a question arises: is it worth designing eco-driving speed profiles? This paper assesses the energy benefits that eco-driving can provide in different scenarios to answer this question. Eco-driving is obtained by means of a multi-objective particle swarm optimization algorithm, combined with a detailed train simulator, to obtain realistic results. Eco-driving speed profiles are compared with a standard driving that performs the same running time. Real data from Spanish high-speed lines have been used to analyze the results in two case studies. Stretches fed by 1 × 25 kV and 2 × 25 kV AC power supply systems have been considered, as they present high receptivity to regenerate energy. Furthermore, the variations of the two most important factors that affect the regenerative energy usage have been studied: train motors efficiency ratio and catenary resistance. Results indicate that the greater the catenary resistance, the more advantageous eco-driving is. Similarly, the lower the motor efficiency, the greater the energy savings provided by efficient driving. Despite the differences observed in energy savings, the main conclusion is that eco-driving always provides significant energy savings, even in the case of the most receptive power supply network. Therefore, this paper has demonstrated that efforts in improving regenerated energy usage must not neglect the role of eco-driving in railway efficiency.
38
Huangfu, Geng, Jianwei Chen, Jie Jiao, Haosu Luo i Yiping Guo. "Domain evolution and coercive field reduction in rhombohedral (Na0.5Bi0.5)TiO3-based crystals by alternating electric field". Applied Physics Letters 122, nr 6 (6.02.2023): 062902. http://dx.doi.org/10.1063/5.0139594.
Pełny tekst źródłaStreszczenie:
(Na0.5Bi0.5)TiO3 (NBT)-based materials have been widely studied for their large electric-field-induced strains. However, a high coercive field ( Ec) has long hindered the applications of NBT-based materials. Here, we propose a simple method to significantly reduce the Ec of rhombohedral NBT-based crystals through domain engineering. By applying an alternating current (AC) electric field along the [001] direction, the Ec of Mn-doped (Na0.485K0.015Bi0.5)TiO3 single crystal can be reduced from 70 to 20 kV/cm after about 25 cycles without sacrificing the ferroelectric polarization. Meanwhile, the piezoelectric coefficient d33 and the optical transparency of the crystals are also enhanced compared with those after direct-current electric field poling. The domain structure characterization shows that the AC cycles can form a laminar domain configuration, in which the 109° domain walls are parallel to (001) planes. It is demonstrated that in the laminar domain configuration, almost only 71° polarization switching occurs when the external electric field is reversed. The required energy for polarization reversal is significantly lower than that of the “4R” domain configuration; thus, the Ec is reduced greatly. The low Ec is maintained after depolarization at 250 °C, evidencing good thermal stability of the laminar domain configuration. Furthermore, this method is also applicable to other rhombohedral single crystals and may be applied to [001]-textured polycrystalline ceramics in the future; thus, it may indeed benefit the practical applications of NBT-based piezoelectric devices.
39
Asghar, Atif H., Omar B. Ahmed i Ahmed Rida Galaly. "Inactivation of E. coli Using Atmospheric Pressure Plasma Jet with Dry and Wet Argon Discharges". Membranes 11, nr 1 (9.01.2021): 46. http://dx.doi.org/10.3390/membranes11010046.
Pełny tekst źródłaStreszczenie:
The acceleration of inactivating viable cells of Escherichia coli (E. coli), by using new direct and indirect innovative methods, is the targeted method of using an atmospheric pressure plasma jet (APPJ) operated by an AC high-voltage power source with variable frequency up to 60 kHz and voltage ranging from 2.5 to 25 kV. Discharges using dry argon (0% O2) discharges and different wet argon discharges using admixtures with O2/Ar ratios ranging from 0.25% to 1.5% were studied. The combined effects of dry and wet argon discharges, direct and indirect exposure using a mesh controller, and hollow magnets were studied to reach a complete bacterial inactivation in short application times. Survival curves showed that the inactivation rate increased as the wettability increased. The application of magnetized non-thermal plasma discharge with a 1.5% wetness ratio causes a fast inactivation rate of microbes on surfaces, and a dramatic decrease of the residual survival of the bacterial ratio due to an increase in the jet width and the enhanced ability of fast transport of the charges to viable cells, especially at the edge of the Petri dish. The membrane damage of E. coli mechanism factors in the activation process by APPJ is discussed.
40
Asghar, Atif H., Omar B. Ahmed i Ahmed Rida Galaly. "Inactivation of E. coli Using Atmospheric Pressure Plasma Jet with Dry and Wet Argon Discharges". Membranes 11, nr 1 (9.01.2021): 46. http://dx.doi.org/10.3390/membranes11010046.
Pełny tekst źródłaStreszczenie:
The acceleration of inactivating viable cells of Escherichia coli (E. coli), by using new direct and indirect innovative methods, is the targeted method of using an atmospheric pressure plasma jet (APPJ) operated by an AC high-voltage power source with variable frequency up to 60 kHz and voltage ranging from 2.5 to 25 kV. Discharges using dry argon (0% O2) discharges and different wet argon discharges using admixtures with O2/Ar ratios ranging from 0.25% to 1.5% were studied. The combined effects of dry and wet argon discharges, direct and indirect exposure using a mesh controller, and hollow magnets were studied to reach a complete bacterial inactivation in short application times. Survival curves showed that the inactivation rate increased as the wettability increased. The application of magnetized non-thermal plasma discharge with a 1.5% wetness ratio causes a fast inactivation rate of microbes on surfaces, and a dramatic decrease of the residual survival of the bacterial ratio due to an increase in the jet width and the enhanced ability of fast transport of the charges to viable cells, especially at the edge of the Petri dish. The membrane damage of E. coli mechanism factors in the activation process by APPJ is discussed.
41
Flumian, Didier, Philippe Ladoux i Emmanuel Sarraute. "Calculation of the Voltage Unbalance Factor for High-Speed Railway Substations with V-Connection Scheme". Electronics 11, nr 4 (15.02.2022): 595. http://dx.doi.org/10.3390/electronics11040595.
Pełny tekst źródłaStreszczenie:
In France, high-speed railway lines are powered by a 2 × 25 kV/50 Hz electrification system. The substations include two single-phase transformers connected to the high-voltage electrical transmission network on different pairs of phases according to a so-called “V-connection scheme”. In practice, due to the large variations in the power absorbed by the trains, this connection does not make it possible to satisfactorily limit the unbalance in the three-phase voltages. In order to correctly size a balancing system to be associated with the substation, it is necessary to calculate, with precision, the voltage unbalance factor as a function of the power drawn by the trains. In its first part, this paper presents modelling of the substation and proposes an algorithm which allows for the calculation of the upstream line voltage as a function of the power consumption at the secondary of the transformers. The voltage unbalance factor can then be determined over a long period of operation. In the second part of this paper, the same approach is applied with an unbalance-compensator based on Steinmetz circuits controlled by AC choppers. Finally, in both cases, the results of the calculations are validated by simulations performed with PLECS simulation software.
42
Minja, Kelvin Melckzedeck, Pius Victor Chombo, Narupon Promvichai i Boonruang Marungsri. "Transient Current Behaviour during Multiple Lightning strokes on Multiple Unit Trains". ECTI Transactions on Electrical Engineering, Electronics, and Communications 15, nr 2 (24.07.2017): 47–56. http://dx.doi.org/10.37936/ecti-eec.2017152.171316.
Pełny tekst źródłaStreszczenie:
This paper studies transient current behaviour during multiple lightning strokes on Multiple Unit trains in pantograph. 2×25 kV AC, 50 Hz Catenary Contact System on double-track elevated railway system which connects Phayathai BTS station in the Centre with Suvarnabhumi Airport in the East of Bangkok was used in the study. This paper investigates effectively in order to reduce breakdown due to overvoltage condition caused by transient current during multiple lightning strokes. The magnitude, front times and tail times of multiple lightning strokes were studied. The assumption of studies based on the return multiple lightning strokes current ranging 1–200 kA, front time of multiple lightning strokes between 1–3 μs, elevated pole resistance of 50 Ω and grounding resistance of 5 Ω. The Catenary Contact System on elevated railway system with Multiple Unit trains and multiple lightning strokes were modelled in ATP-EMTP software. The effect of varying front time of multiple lightning strokes, transient current and mast induced voltage were studied in simulations. Simulations showed that the peak amplitude of mast induced voltage tend to increase when the negative multiple lighting strokes on Multiple Unit trains in pantograph at elevated pole than it is between elevated poles in different front times.
43
KOCAARSLAN, İlhan, Mehmet Taciddin AKÇAY, Sırrı Erdem ULUSOY, Emrah BAL i Hasan TİRYAKİ. "Creation of a dynamic model of the electrification and traction power system of a 25 kV AC feed railway line together with analysis of different operation scenarios using MATLAB/Simulink". TURKISH JOURNAL OF ELECTRICAL ENGINEERING & COMPUTER SCIENCES 25 (2017): 4254–67. http://dx.doi.org/10.3906/elk-1612-84.
Pełny tekst źródła
44
Chanioti, Sofia, Nikolaos Katsenios, Aspasia Efthimiadou, Panagiota Stergiou, Zacharoula-Maria Xanthou, Marianna Giannoglou, Panagiotis Dimitrakellis, Evangelos Gogolides i George Katsaros. "Pre-sowing treatment of maize seeds by cold atmospheric plasma and pulsed electromagnetic fields: Effect on plant and kernels characteristics". Australian Journal of Crop Science, nr 15(02):2021 (3.02.2021): 251–59. http://dx.doi.org/10.21475/ajcs.21.15.02.p2932.
Pełny tekst źródłaStreszczenie:
The effect of cold atmospheric plasma (CAP) (45 kHz sinusoidal AC high voltage at 6 kV peak-to-peak for 5-15 min) and pulsed electromagnetic fields (PEMF) (amplitude 12.5 mT, repetitive frequency 3 Hz for 30 min) as pre-sowing treatments was studied on the germination, physiology, yield and quality characteristics of maize hybrid seeds with high and low germination capability. The measurements conducted during the plant growth were the dry weight, chlorophyll content, photosynthetic rate, transpiration rate and stomatal conductance, while for the harvested kernels, the color, texture, sphericity, size, ash, total protein and total crude content were estimated. The results showed that CAP and PEMF pre-sowing treatments favored the growth and physiology of both maize plants improving their germination rate significantly. Their chlorophyll content, photosynthetic rate, transpiration rate, stomatal conductance as well as dry weight were also improved. Both CAP and PEMF treatments, resulted in maize yield increase by 18-25% and by 10-20% compared to untreated samples for the low and high germination capability seeds, respectively. With regards to the quality of the harvested corn grains, their total protein and crude fiber content obtained by CAP treatment for 15 min were significantly increased by 26% and 29% for low germination seeds and by 36% and 42% for high germination seeds, respectively, compared to untreated samples. The results indicate that either CAP or PEMF pre-sowing treatments could be used as alternative ameliorative tools in order to improve maize growth, productivity, yield and quality of the final products
45
Noskov, M. Yu, M. M. Ginshparg i N. S. Nesterov. "Results of tests on the indicator of external noise of electric locomotives in the standing time". Vestnik of the Railway Research Institute 76, nr 5 (28.10.2017): 301–5. http://dx.doi.org/10.21780/2223-9731-2017-76-5-301-305.
Pełny tekst źródłaStreszczenie:
The authors of the Test Loop of the JSC “VNIIZhT” had conducted tests of mainline electric locomotives intended for handling freight trains on sections of the road electrified with alternating current at a voltage of 25 kV (electric locomotives of an alternating current). Tests were conducted in terms of the level of external noise at the standing time. The results of tests of AC electric locomotive, which was in a stationary mode, are presented in terms of the external noise index, and a methodology for performing these tests is described. As a result of the conducted researches, the article establish the main sources of external noise in the operation of AC electric locomotives (fans intended for cooling electrical equipment and traction motors, air compressors, traction transformers, etc.), its actual values, as well as the nature of the sound field around electric locomotives. The analysis of the obtained sound field made it possible to identify the points where the excess of the standard noise values (more than 65 dBA) is observed. It is proposed to bring the technical condition of the equipment, such as traction transformer, converter and cooling module of the traction engine of the power compartment of an electric locomotive in accordance with the normative documentation. The repeated measurements of the external noise level after technical completion did not reveal the excess of its normative values in accordance with the regulatory documentation. In order to provide a normative margin in terms of the external noise of an electric locomotive, it is proposed to use sound-absorbing material in the construction of its body. It is recommended to perform an experimental study of the spectral composition of the noise of the equipment of an electric locomotive operating at the standing time and the resulting external noise at points located outside and around the locomotive in order to calculate the acoustic characteristics of sound-absorbing materials. Sound absorbing material is expedient to be selected depending on the frequency range in which the greatest excess is observed above the maximum permissible values using known empirical and semi-empirical dependences, on the basis of which it is possible to preliminary determine its sound-absorbing properties in the frequency range established by regulatory documents. After equipping the power compartment of the locomotive with soundproof materials, tests on the evaluation of the external noise of an electric locomotive at standing should be repeated.
46
Nur, Muhammad, Ade Ika Susan, Zaenul Muhlisin, Fajar Arianto, Andi Wibowo Kinandana, Iis Nurhasanah, Sumariyah Sumariyah, Pratama Jujur Wibawa, Gunawan Gunawan i Anwar Usman. "Evaluation of Novel Integrated Dielectric Barrier Discharge Plasma as Ozone Generator". Bulletin of Chemical Reaction Engineering & Catalysis 12, nr 1 (30.04.2017): 24. http://dx.doi.org/10.9767/bcrec.12.1.605.24-31.
Pełny tekst źródłaStreszczenie:
<p>This paper presents a characterization of an integrated ozone generator constructed by seven of reactors of Dielectric Barrier Discharge Plasma (DBDP). DBDP a has spiral-cylindrical configuration. Silence plasma produced ozone inside the DBDP reactor was generated by AC-HV with voltage up to 25 kV and maximum frequency of 23 kHz. As a source of ozone, dry air was pumped into the generator and controlled by valves system and a flowmeter. We found ozone concentration increased with the applied voltage, but in contrary, the concentration decreased with the flow rate of dry air. It was also found that a maximum concentration was 20 mg/L and ozone capacity of 48 g/h with an input power of 1.4 kW. Moreover, in this generator, IP efficiency of 8.13 g/kWh was obtained at input power 0.45 kW and air flow rate of 9 L/min. Therefore, be the higher ozone capacity can be produced with higher input power; however, it provided lower IP efficiency. The effect of dry air flow rate and applied voltage on ozone concentrations have been studied. At last, spiral wire copper was very corrosive done to the interaction with ozone, and it is necessary to do a research for finding the best metals as an active electrode inside of the quartz dielectric. Copyright © 2017 BCREC GROUP. All rights reserved</p><p><em>Received: 18<sup>th</sup> July 2016; Revised: 25<sup>th</sup> September 2016; Accepted: 5<sup>th</sup> October 2016</em></p><p><strong>How to Cite:</strong> Nur, M., Susan, A.I., Muhlisin, Z., Arianto, F., Kinandana, A.W., Nurhasanah, I., Sumariyah, S., Wibawa, P.J., Gunawan, G., Usman, A. (2017). Evaluation of Novel Integrated Dielectric Barrier Discharge Plasma as Ozone Generator. <em>Bulletin of Chemical Reaction Engineering & Catalysis</em>, 12 (1): 24-31 (doi:10.9767/bcrec.12.1.605.24-31)</p><p><strong>Permalink/DOI</strong>: http://dx.doi.org/10.9767/bcrec.12.1.605.24-31</p><p> </p>
47
Ohlweiler, L. U., J. C. Mezzalira, E. Monaco, A. Mezzalira, M. Bertolini, S. M. Wilson, J. Ringwelski, R. L. Krisher, L. A. Rund i M. B. Wheeler. "72 PREGNANCY OUTCOME AFTER OVIDUCTAL TRANSFER OF ZONA-FREE 1-CELL-STAGE PORCINE EMBRYOS PRODUCED BY HANDMADE CLONING". Reproduction, Fertility and Development 22, nr 1 (2010): 194. http://dx.doi.org/10.1071/rdv22n1ab72.
Pełny tekst źródłaStreszczenie:
The pig is an important animal model for the study of human diseases. An important step for better use of this species in biomedical research is to obtain genetically identical individuals by procedures such as somatic cell nuclear transfer (SCNT). As the in vitro culture environment is usually sub-optimal for embryo development, the oviductal transfer of cloned embryos at the 1-cell stage may be more efficient for the establishment of pregnancies. However, the transfer at such an early stage usually requires the presence of zona pellucida or agar embedding to protect embryos from the recipient’s immune system (Loi et al. 1999 Livest. Prod. Sci. 60, 281-294). This study aimed to evaluate the developmental viability of 1-cell-stage porcine handmade cloned embryos directly transferred to the oviduct of female recipients without the zona pellucida or agar embedding. After 40 h of IVM in TCM-199 +10% follicular fluid, COCs obtained from sows were denuded, selected for the presence of a polar body (459/689), and submitted to a 0.2% pronase solution in 25% fetal bovine serum (FBS) for partial zona removal, followed by rinses in manipulation medium and pure FBS. Subsequent to oocyte splitting by manual bisection in a 5 μg mL-1 cytochalasin B solution (CCB), hemi-oocytes (87.1%) were screened under fluorescent microscopy using Hoechst 33 342 stain, resulting in 57.6% enucleated halves (461/800). A somatic cell culture established from a fetal clone pig biopsy (Adam et al. 2007 Oncogene 26, 1038-1045) at passage 4 was used for embryo reconstruction, which was done in a 0.05% phytohemagglutinin (PHA) solution, by sticking 2 cytoplasts and a somatic cell in a linear orientation. Reconstructed couplets, rinsed in calcium- and magnesium-free fusion medium, were electrofused in a fusion chamber after exposure to a 30-V AC pulse for 20 s for alignment, followed by two 24-μs-long DC fusion pulses of 1.3 kV cm-1. Fused couplets (154/214) were exposed for 10 min to a solution containing 5 μg mL-1 CCB and 10 μg mL-1 cycloheximide, followed by electrical activation (two 24-μs-long DC pulses of 0.9 kV cm-1) in fusion medium containing calcium and magnesium. Activated embryos were cultured in vitro for 12 h in 500 μL of PZM-3 medium in the well of the well (WOW) system, in a plastic bag filled with gas mixture (90% N2, 5% O2, 5% CO2), at 38.5°C. Then, a total of 70 and 80 non-agar-embedded, zona-free 1-cell-stage cloned porcine embryos were transferred directly to the oviducts of a sow and a gilt, respectively, both synchronous at approximately 12 h before ovulation. The recipient sow was diagnosed pregnant by ultrasonography on Day 66 of gestation. Although the sow was diagnosed open on Day 72, this study demonstrates that the transfer of 1-cell-stage zona-free embryos directly to the oviduct of a synchronous sow can result in pregnancy.
48
Grigor’ev, N. P., I. V. Ignatenko, S. A. Vlasenko, V. A. Kovalev i V. V. Shatalov. "Increasing the performance of the Far Eastern Railway traction power supply system". RUSSIAN RAILWAY SCIENCE JOURNAL 81, nr 3 (21.09.2022): 248–57. http://dx.doi.org/10.21780/2223-9731-2022-81-3-248-257.
Pełny tekst źródłaStreszczenie:
Introduction. The purpose of the study is to develop measures determined by the strategic programmes for the development of Russian railway transport based on the analysis of power supply schemes for the traction network of the Far Eastern Railway, a branch of Russian Railways.Materials and methods. Evaluation of the performance of the traction power supply system was made based on the analysis of the actual performance of the Far Eastern Railway section, as well as the theories of electrical engineering and power supply of the 25 kV AC electrified railway system.Results. Based on the analysis of the joint operation of the external and traction power supply systems of the Far Eastern Railway, four traction substations with low technical and economic indicators were identified. Network sections that feed the substations are a bottleneck in the traction power supply system. It is proposed to increase the efficiency by switching the connection of the windings of transformers of traction substations to the systems of external and traction power supply according to the typical star – delta scheme. Such a connection will ensure an increase in the speed of trains, a reduction in train succession time and losses of electricity, an increase in the quality of electric energy in the external power supply system and electric networks of the Far Eastern Directorate for Energy Supply (a structural subdivision of Transenergo, a branch of Russian Railways).Discussion and conclusion. Normalisation of the connection of four traction substations according to the feeding scheme is ensured by changing the phasing in such a way that the power supply of the two legs of one winding of the power transformer is transferred to two windings. Alignment of the current modules in the windings of transformers of traction substations makes it possible to reduce the voltage drop in the most loaded phase and, accordingly, increase the voltage in the traction network, which ensures an increase in the speed of trains and a reduction in passing intervals. Switching the power supply of the arms from one winding of the transformer to two reduces the loss of electrical energy in power transformers and the external power supply system. Reducing the current unbalance in the windings of the power transformer improves the quality of electrical energy in the system of external and district power supply. An increase in the service life of the power transformer is ensured by a decrease in the intensity of thermal wear of the insulation of the most loaded winding.
49
Mukha, A., D. Ustymenko, R. Krasnov i Mohammad Al Said Ahmad. "THE RESULTS OF BENCH TESTS OF THE SLIDING CONTACT OF ELECTRIC TRANSPORT TO DETERMINE THE WEAR OF THE CONTACT WIRE". Electromechanical and energy saving systems 4, nr 56 (grudzień 2021): 47–55. http://dx.doi.org/10.30929/2072-2052.2021.4.56.47-55.
Pełny tekst źródłaStreszczenie:
Purpose. Electric rolling stock of railways receives power from a 25 kV AC or 3 kV DC overhead contact network using a high-current sliding contact that transfers energy to locomotive or electric train, while the current can reach values of 2500 A. Of course, the reliability of this sliding contact determines the operational reliability of the unit. electric transport in general. The pantograph of an electric locomotive or electric train is equipped with a pantograph – a pantograph with contact strip, which should damage and wear it to a minimum when sliding along the contact wire. When introducing new materials for pantograph contact strip, they must pass tests, among which there are bench tests to determine the wear of the contact wire. The purpose of the research is to determine the possibility of using various types of linings on the electric rolling stock of railways, with the determination of the value of the wear of the contact wire and its comparison with the standard. Methodology. The main research method is an experiment on a test bench with control of the main indicators, which include – contact current, clamping force, speed of rotation of the disk of the test bench, temperature in the contact zone. The method of bench tests is standardized, in accordance with DSTU GOST 32680: 2016. Results. During the experiments on the test bench, six types of pantograph contact strips were investigated, and the indicators on the amount of contact wire wear were obtained. Determination of the wear of the contact wire is carried out as the difference between the heights of the contact wire before and after the experiment. The wear values of the contact wire were recorded every 10 thousand passes of the test bench disk. The obtained values of wear are stochastic probabilistic in nature, so they were processed by methods of mathematical statistics to determine the value of the mathematical expectation of the amount of wear of the contact wire. Based on the obtained values, the relationships between the amount of wear of the contact wire and the number of revolutions of the test disk of the stand are constructed. Originality. The scientific novelty of the research lies in the obtained relationships between the number of passes and contact wire wear for different types of samples of pantograph contact strips of electric rolling stock of railways, which allows to determine the contact wire resource when implementing different types of current collector inserts. Practical value. The main purpose of bench tests is to reproduce the conditions of actual operation with certain restrictions. Test specimens in bench tests were in the same conditions, so the obtained values of wear of the contact wire for different types of contact strips allow to estimate the possible service life of the sliding high-current contact in real operating conditions. The obtained values are relative, the first type of inserts is accepted as a base sample, which allows to determine the quantitative indicators of wear of contact strips in comparison with this reference sample. The normative value of contact wire wear is 40 μm per 10 thousand passes of the test bench disk. The tests are considered successful if the wear of the contact wire does not exceed the specified standard value. According to the test results, three samples of contact strips were identified, the use of which will not lead to wear of the contact wire above the normative value. Analytical expressions are obtained for three types of contact strips, with the help of which it is possible to obtain comparative values of resource indicators of sliding high-current contact. Figures 11, tables 2, references 13.
50
Cheng, Ziyi, Zhenhua Li, Yuehua Huang, Weifang Yao i Huichun Xie. "Invalid Data Rejection of Audible Noise on AC Transmission Lines Based on Moving Window Kernel Principal Component Analysis". Frontiers in Energy Research 9 (5.11.2021). http://dx.doi.org/10.3389/fenrg.2021.775519.
Pełny tekst źródłaStreszczenie:
The statistical characteristics of the nighttime noise data of 1000 kV AC transmission lines were investigated, the noise data of the Huainan-Shanghai 1000 kV AC transmission line collected at night (0:00 to 6:00) from September 25, 2015, to February 16, 2016, were statistically analyzed using the nonparametric statistical K-S test, and the outliers were detected using the moving window kernel principal component analysis (MWKPCA). The results show that after the ineffective data are removed by MWKPCA, the 5, 50, and 95% values of the data are basically unchanged. To a certain extent, the method proposed in this paper can remove the invalid audible noise (AN) data of 1000 kV AC transmission lines without affecting the subsequent study of AN, we use various machine learning algorithms to predict the A weight sound level (Awsl) before and after the invalid data rejection, and the results show that the invalid data rejection has contributed to the improvement of the transmission line AN Awsl prediction accuracy.