Artículos de revistas: "Alternating current network"

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Kovaleva, T. V., O. O. Komyakova y N. V. Pashkova. "Resonance in alternating current traction network". Omsk Scientific Bulletin, n.º 172 (2020): 32–35. http://dx.doi.org/10.25206/1813-8225-2020-172-32-35.

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Rote, Günter. "Characterization of the Response Maps of Alternating-Current Networks". Electronic Journal of Linear Algebra 36, n.º 36 (14 de octubre de 2020): 698–703. http://dx.doi.org/10.13001/ela.2020.4981.

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In an alternating-current network, each edge has a complex conductance with positive real part. The response map is the linear map from the vector of voltages at a subset of boundary nodes to the vector of currents flowing into the network through these nodes. In this paper, it is proved that the known necessary conditions for a linear map to be a response map are sufficient, and we show how to construct an appropriate network for a given response map.

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3

Abbas, Zainab Nadhim y Firas Mohammed Tuaimah. "Stability Improvement of The Iraqi Super Grid (400kV) using High Voltage Direct Current (HVDC) Transmission". Journal of Engineering 27, n.º 11 (1 de noviembre de 2021): 64–74. http://dx.doi.org/10.31026/j.eng.2021.11.05.

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This research analyzes the level of the short circuit effect of the Iraqi super network and decides the suitable location for the High Voltage Direct Current (HVDC) connections in order to obtain the best short circuit reduction of the total currents of the buses in the network. The proposed method depends on choosing the transmission lines for Alternating current (AC) system that suffers from high Short Circuit Levels (SCLs) in order to reduce its impact on the transmission system and on the lines adjacent to it and this after replacing the alternating current (AC) line by direct current (DC) line. In this paper, Power System Simulator for Engineering (PSS/E) is used to model two types of HVDC lines in an effective region of Iraqi networks and to perform comparative studies to test the location of Short Circuit Levels (SCLs) between an actual AC and AC/DC case study in a portion of the Iraqi national network. The results proved the effectiveness of this method in eliminating severe faults and unwanted short currents, and the results showed that the bipolar type is better in reducing Short Circuit Levels of the Iraqi network.

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4

Ali, M. M., K. K. Sellers y F. Frohlich. "Transcranial Alternating Current Stimulation Modulates Large-Scale Cortical Network Activity by Network Resonance". Journal of Neuroscience 33, n.º 27 (3 de julio de 2013): 11262–75. http://dx.doi.org/10.1523/jneurosci.5867-12.2013.

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5

Ahn, Sangtae, Diamond Gleghorn, Benjamin Doudican, Flavio Fröhlich y Yoon‐Hee Cha. "Transcranial Alternating Current Stimulation Reduces Network Hypersynchrony and Persistent Vertigo". Neuromodulation: Technology at the Neural Interface 24, n.º 5 (23 de marzo de 2021): 960–68. http://dx.doi.org/10.1111/ner.13389.

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6

Helfrich, R. F. y T. R. Schneider. "Modulation of Cortical Network Activity by Transcranial Alternating Current Stimulation". Journal of Neuroscience 33, n.º 45 (6 de noviembre de 2013): 17551–52. http://dx.doi.org/10.1523/jneurosci.3740-13.2013.

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7

Tallman, Tyler N. y Hashim Hassan. "A computational exploration of the effect of alignment and aspect ratio on alternating current conductivity in carbon nanofiber–modified epoxy". Journal of Intelligent Material Systems and Structures 31, n.º 5 (13 de enero de 2020): 756–70. http://dx.doi.org/10.1177/1045389x19898252.

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Carbon nanofiller–modified polymers have been the subject of intense study for years due to their potential use in diverse and far-reaching applications. The effect of nanofiller network parameters on macroscale direct current electrical transport has been thoroughly elucidated by extensive nano-to-microscale modeling. As a result, we now have great insight into how the conductive and piezoresistive properties of nanocomposites can be tailored through judicious control of the underlying nanofiller network. It is also well-known that carbon nanofiller–modified polymers possess frequency-dependent alternating current electrical properties. Even though work has been done to understand the alternating current properties of nanocomposites via experimental characterization and through the development of macroscale equivalent circuit models, much less has been done to understand how macroscale alternating current conductivity depends on microscale effects such as nanofiller alignment and aspect ratio. This is an important knowledge gap because, like direct current conductivity, the underlying nanofiller network ultimately gives rise to macroscale alternating current transport in these materials. To this end, we herein present an alternating current microscale percolation model for carbon filler–based polymer nanocomposites. After calibration against experimental complex impedance data from randomly ordered carbon nanofiber–modified epoxy, this model is used to explore the effect of carbon nanofiber alignment and aspect ratio on alternating current conductivity. These simulations show that alternating current conductivity generally increases with increasing alignment and with aspect ratio; however, the competing effects of alternating current and direct current percolation give rise to substantial variation in alternating current conductivity at low frequencies and with poor percolation. The methodology presented in this article provides a modeling tool by which nanocomposites with highly optimized alternating current properties can be developed through careful control and tailoring of nanofiller network properties for the realization of exotic, next-generation material functionality.

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Shuin, V. A., O. A. Dobryagina, Yu D. Kutumov y T. Yu Shadrikova. "The influence of higher harmonics on transients during arcing earth faults in 6–10 kV cable networks with insulated neutral". Vestnik IGEU, n.º 2 (2020): 30–40. http://dx.doi.org/10.17588/2072-2672.2020.2.030-040.

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Alternating arc single-phase earth faults in 6–10 kV cable networks with insulated neutral are accompanied by over-voltages and a significant increase in the root-mean-square current value at the fault location. When evaluating the specified parameters of transient voltages and currents during arc earth faults, as a rule, the presence of higher harmonics in earth fault current is not taken into account. At the same time, in modern systems of industrial and urban electricity supply, the customers with nonlinear current-voltage characteristics are widely used. They caused a significant increase in the share of higher harmonics in earth fault currents of more than 40–55 % of the total network capacitive current determined at the fundamental frequency of 50 Hz. With such correlations between the levels of the fundamental frequency component and higher harmonics, higher harmonics can have a significant effect on the conditions of quenching and reignition of grounding arcs and, accordingly, on the parameters of transient voltages and currents in intermittent arc earth faults. Simulation in Matlab with SimPowerSystem was used to study the influence of higher harmonics in earth fault current on transient voltages and currents in 6–10 kV cable networks with insulated neutral. Modeling of alternating arc faults was carried out on the basis of existing theories of the occurrence of maximum overvoltages during arc earth faults in networks with isolated neutral developed by W. Petersen and Belyakov N.N. On the basis of computational experiments on simulation models of 6–10 kV cable networks with different values of the total capacitive current, it was shown that in the case of arc alternating earth faults the presence of higher harmonics in the earth fault current can lead to an increase in the multiplicity of overvoltages in intact phases by 13–16 % and the root-mean-square value of the current at the fault location by up to 22 %. Higher harmonics in earth fault current can have a significant effect on the conditions of extinction and reignition of the grounding arc, leading to an increase in the time of its extinction, the multiplicity of the maximum overvoltage level and root-mean-square value of fault current during alternating arc faults, which should be taken into account when evaluating the network efficiency in the isolated neutral mode.

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9

German, L. A., A. S. Serebryakov, V. L. Osokin y K. S. Subkhanverdiev. "Equivalent Scheme for Calculating Short-Circuit Current in an Alternating-Current Electric Traction Network". Russian Electrical Engineering 90, n.º 7 (julio de 2019): 516–21. http://dx.doi.org/10.3103/s1068371219070058.

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10

Fuscà, Marco, Philipp Ruhnau, Toralf Neuling y Nathan Weisz. "Local Network-Level Integration Mediates Effects of Transcranial Alternating Current Stimulation". Brain Connectivity 8, n.º 4 (mayo de 2018): 212–19. http://dx.doi.org/10.1089/brain.2017.0564.

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Liu, Tiantian, Zilong Yan, Ziteng Han, Jian Zhang, Boyan Fang y Tianyi Yan. "Cortico–subcortical spatiotemporal dynamics in Parkinson’s disease can be modulated by transcranial alternating current stimulation". Brain Science Advances 9, n.º 2 (junio de 2023): 114–35. http://dx.doi.org/10.26599/bsa.2023.9050009.

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Objective: We investigated changes in cortico–subcortical spatiotemporal dynamics to explore the treatment mechanisms of transcranial alternating current stimulation (tACS) in patients with Parkinson’s disease (PD). Methods: Resting-state functional magnetic resonance imaging (rs-fMRI) data were collected from 20 patients with PD and 20 normal controls (NC). Each patient with PD received successive multidisciplinary intensive rehabilitation treatment and tACS treatment over a one-year interval. Individual functional brain network mapping and co-activation pattern (CAP) analysis were performed to characterize cortico–subcortical dynamics. Results: The same tACS electrode placement stimulated different proportions of functional brain networks across the participants. CAP analysis revealed that the visual network, attentional network, and default mode network co-activated with the thalamus, accumbens, and amygdala, respectively. The pattern characterized by the de-activation of the visual network and the activation of the thalamus showed a significantly low amplitude in the patients with PD than in NCs, and this amplitude increased after tACS treatment. Furthermore, the co-occurrence of cortico–subcortical CAPs was significantly higher in patients with PD than in NCs and decreased after tACS treatment. Conclusions: This study investigated cortico–subcortical spatiotemporal dynamics in patients with PD and further revealed the tACS treatment mechanism. These findings contribute to understanding cortico– subcortical dynamics and exploring noninvasive neuromodulation targets of cortico–subcortical circuits in brain diseases, such as PD, Alzheimer’s disease, and depression.

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Gębura, Andrzej y Tomasz Tokarski. "Selected Problems In Controlling On-Board Direct And Alternating Current Systems". Research Works of Air Force Institute of Technology 36, n.º 1 (1 de agosto de 2015): 109–30. http://dx.doi.org/10.1515/afit-2015-0018.

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AbstractThe article addresses in a complex way the problem of cooperation between the on-board electric power sources of an aircraft with its on-board electric network. The authors paid special attention to conditions related to correct switching of the on-board electric power sources. Structural protection of the electric power sources against harmful impact of loads, and of the loads against incorrectly operating sources, as well as certain methods to counteract such phenomena, are discussed. Exploring these relations will enable the user to undertake actions which can reduce the failure rate of the on-board electrical power network, and ensure power supply to the electrical loads under all flight conditions. Their correct operation determines correct operation of the on-board electrical power network. The authors tried to discuss all the problems in the most universal way possible, so the deliberations presented here could be helpful in analyzing defects in various aircrafts.

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13

Fikrət oğlu Qurbanov, Elcan. "Improving the energy efficiency of reactive power compensated power supply systems in alternating current networks". SCIENTIFIC RESEARCH 09, n.º 5 (22 de mayo de 2022): 138–42. http://dx.doi.org/10.36719/2789-6919/09/138-142.

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Dəyişən cərəyan şəbəkələrində reaktiv güc kompensasiyası elektrik təchizatı sisteminin enerji səmərəliliyini artırmağa imkan verir ki, bu da dəmir yolu hissəsinin çıxıntı və daşıma qabiliyyətinin artmasına gətirib çıxarır. Dartı yarımstansiyasında reaktiv güc şaquli kompensasiya cihazının keçid mərhələsinin seçilməsi dartıcının yükünün simmetrikləşdirilməsi zərurəti ilə müəyyən edilir. Reaktiv güc şaquli kompensasiya qurğularını dartı yarımstansiyasında faza geri qalma mərhələsinə daxil etmək tövsiyə olunur. Qeyd edək ki, RGK-nın quraşdırılması zamanı dartı güc təchizatı şəbəkəsinin kontakt şəbəkəsində gərginlik artımı 29 kV-a bərabər maksimum icazə verilən qiymətdən çox olmamalıdır. Müqavimət seçimi halında digər yarımstansiyalardan olan yüklərin minimal qiymətini nəzərə almaq zəruridir. Açar sözlər: kontakt şəbəkəsi, dartı elektrik təchizatı sistemi, reaktiv güc kompensasiyası, dartı şəbəkəsi, şaquli kompensasiya, reaktiv gücün şaquli kompensasiyası Eljan Fikret Gurbanov Improving the energy efficiency of reactive power compensated power supply systems in alternating current networks Abstract Reactive power compensation in alternating current networks allows to increase the energy efficiency of the power supply system, which leads to an increase in the protrusion and carrying capacity of the railway section. The selection of the transition phase of the reactive power vertical compensation device at the traction substation is determined by the need to symmetrize the traction load. It is recommended that reactive power vertical compensation devices be included in the phase lag phase at the traction substation. It should be noted that during the installation of the RGK, the voltage increase in the contact network of the traction power supply network should not exceed the maximum allowable value of 29 kV. In the case of resistance selection, it is necessary to take into account the minimum cost of cargo from other substations. Key words: contact network, traction power supply system, reactive power compensation, traction network, vertical compensation, vertical reactive power compensation

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Supriyono, Heru. "Telecontrol of Alternating Current Motor with Star Delta Starter using Computer Network". International Journal of Advanced Trends in Computer Science and Engineering 9, n.º 3 (25 de junio de 2020): 2769–74. http://dx.doi.org/10.30534/ijatcse/2020/44932020.

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15

Belinsky, S. y K. Kuznetsov. "Modeling the distribution of magnetic field induction in alternating current contact network". Systems. Methods. Technologies, n.º 2 (38) (2018): 76–82. http://dx.doi.org/10.18324/2077-5415-2018-2-76-82.

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16

Rubijanto, J. P., Rusnaldy y D. H. Gunawan. "Inspecting Power Network Analysis on Eddy Current Test of SMAW Joints". E3S Web of Conferences 359 (2022): 01007. http://dx.doi.org/10.1051/e3sconf/202235901007.

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Eddy Current Test (ECT) is proven to be the most reliable non-destructive assessment for electrically conductive materials. This assessment works based on the emerging Eddy Current when an alternating current is induced into conductive materials. The ECT system consists of three elements, i.e. current injection, the pick-up, and the conductive target. This system is then treated as an altered wireless power network between aforementioned elements. The use of alternating current (A/C) in this network provides a wide variety of power spectra for various analysis techniques. This paper introduces novel technique of subsurface crack assessment on SMAW welded joint of stainless steel 316 L by applying network altered response to ECT system. The analysis of the network is done by constructing mathematical models of the frequency domain in each component in the network to achieve the gain of the system. The mathematical model was constructed either for the defectless and the defected speciments, and then both result was compared to investigate and extract the information about the crack. The experiment also performed to confirm the simulation from the modeling. The experiment succeeded to differentiate the size of the subsurface crack on certain working frequencies.

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17

Antal, Andrea y Christoph S. Herrmann. "Transcranial Alternating Current and Random Noise Stimulation: Possible Mechanisms". Neural Plasticity 2016 (2016): 1–12. http://dx.doi.org/10.1155/2016/3616807.

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Background. Transcranial alternating current stimulation (tACS) is a relatively recent method suited to noninvasively modulate brain oscillations. Technically the method is similar but not identical to transcranial direct current stimulation (tDCS). While decades of research in animals and humans has revealed the main physiological mechanisms of tDCS, less is known about the physiological mechanisms of tACS.Method. Here, we review recent interdisciplinary research that has furthered our understanding of how tACS affects brain oscillations and by what means transcranial random noise stimulation (tRNS) that is a special form of tACS can modulate cortical functions.Results. Animal experiments have demonstrated in what way neurons react to invasively and transcranially applied alternating currents. Such findings are further supported by neural network simulations and knowledge from physics on entraining physical oscillators in the human brain. As a result, fine-grained models of the human skull and brain allow the prediction of the exact pattern of current flow during tDCS and tACS. Finally, recent studies on human physiology and behavior complete the picture of noninvasive modulation of brain oscillations.Conclusion. In future, the methods may be applicable in therapy of neurological and psychiatric disorders that are due to malfunctioning brain oscillations.

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Mishchenko, T. M. "Theoretical aspects and methods of the parameters identification of the electric traction system devices. The instantaneous powers method; series connection of elements". Science and Transport Progress, n.º 42 (25 de diciembre de 2012): 121–26. http://dx.doi.org/10.15802/stp2012/9301.

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Introduction: By means of the mathematical or computer (imitating) modeling the emergency, especially stochastic, transient electromagnetic and / or electro energetic processes in the electric traction system of the alternating current should be investigated. It allows expanding the research opportunities, as well as simplifying and reducing the actual testing, because it permits the wide variation of values and parameters reality of the elements of electric power circuits in the traction system without considerable material costs. Purpose: For this purpose the mathematical model of the nonlinear dynamical system "traction substation – electric traction network – electric rolling stock» as a passive two-terminal network with the given input voltage and input current is proposed. Task: The identification problem of the device under study, therefore the two-terminal network, is the determination electrical parameters (active resistance to inductance and capacity) of the passive elements, which substitute the two-terminal network. The scheme of its substitution looks like the series connection of passive elements. Methodology: The method of solving this problem for the passive two-terminal network in the traction mode with alternating, nonsinusoidal, deterministic periodic input voltage and input current is proposed. The calculations are executed for the electric locomotives DS3 and 2ES5K. Results: The results for the parameters can be applied in the further calculations of the more complex electric traction systems of the alternating current.

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Kovaleva, T. V., O. O. Komyakova y N. V. Pashkova. "Wave processes in alternating current traction network depending on parameters of power supply system". Omsk Scientific Bulletin, n.º 165 (2019): 23–27. http://dx.doi.org/10.25206/1813-8225-2019-165-23-27.

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Kaitwanidvilai, S. y P. Piyarungsan. "Low-cost microprocessor-based alternating current voltage controller using genetic algorithms and neural network". IET Power Electronics 3, n.º 4 (2010): 490. http://dx.doi.org/10.1049/iet-pel.2009.0035.

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21

Brahmaiah, V. Siva y Manav Adhikari. "THE ANALYSIS OF DYNAMIC RESPONSE AND VOLTAGE FLICKER WITH STATCOM ON DISTRIBUTION NETWORK". International Journal of Engineering Technologies and Management Research 4, n.º 4 (31 de enero de 2020): 27–33. http://dx.doi.org/10.29121/ijetmr.v4.i4.2017.79.

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The Flexible Alternating Current Transmission Systems (FACTS) device deals with the control of power flow, alternating current of transmission line and immediately respond towards the stability problems of the system. The present paper show that how the FACTS device STATCOM enhance the dynamic response and voltage flicker in distribution network of the power systems. In MATLAB a simplified distribution system is modeled and the find out the desired objectives. D-STATCOM changes from inductive to capacitive operation, the modulation index of the PWM inverter is increased from 0.56 to 0.9 which corresponds to a proportional increase in inverter voltage. Reversing of reactive power is very fast, about one cycle, as observed on D-STATCOM current. Observed on Scope that voltage fluctuation at bus B3 is now reduced to +/- 0.7 %. The D-STATCOM compensates voltage by injecting a reactive current modulated and varying between 0.6 pu capacitive when voltage is low and 0.6 pu inductive when voltage is high.

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Khan, Muhammad Omer, Abdul Wadood, Muhammad Irfan Abid, Tahir Khurshaid y Sang Bong Rhee. "Minimization of Network Power Losses in the AC-DC Hybrid Distribution Network through Network Reconfiguration Using Soft Open Point". Electronics 10, n.º 3 (1 de febrero de 2021): 326. http://dx.doi.org/10.3390/electronics10030326.

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The Alternating Current-Direct Current (AC-DC) hybrid distribution network has received attention in recent years. Due to advancement in technologies such as the integration of renewable energy resources of DC–type output and usage of DC loads in the distribution network, the modern distribution system can meet the increasing energy demand with improved efficiency. In this paper, a new AC-DC hybrid distribution network architecture is analyzed that considers distributed energy resources (DER) in the network. A network reconfiguration scheme is proposed that uses the AC soft open point (AC-SOP) and the DC soft open point (DC-SOP) along with an SOP selection algorithm for minimizing the network power losses. Subsequently, the real-time data for DER and load/demand variation are considered for a day-a-head scenario for the verification of the effectiveness of the network reconfiguration scheme. The results show that the proposed network reconfiguration scheme using AC-SOP and DC-SOP can successfully minimize the network power losses by modifying the network configuration. Finally, the effectiveness of the proposed scheme in minimizing the network power losses by the upgraded network configuration is verified by constructing an AC-DC hybrid distribution network by combining two IEEE 33-bus distribution networks.

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23

Omelʹchuk, A. O. "STUDY OF RESONANCE PHENOMENA IN THE ELECTRICAL CIRCUIT OF A 10/0.4 KV POWER TRANSFORMER WITH A CAPACITOR BATTERY". Praci Institutu elektrodinamiki Nacionalanoi akademii nauk Ukraini 2023, n.º 66 (4 de diciembre de 2023): 21–26. http://dx.doi.org/10.15407/publishing2023.66.021.

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The processes in the electrical network with power transformers 10/0.4 kV with capacitor banks were investigated for the occurrence of resonance of voltages and currents at the main frequency of three-phase alternating current 50 Hz, as well as at frequencies of 150, 250, 350 and 550 Hz, caused by higher harmonic components voltage and current. Graphs showing resonance processes in specific circles are given. Bible 4, fig. 4., tab. 3. Keywords: capacitor battery, Q factor, frequency, resonance of voltages and currents.

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Ayiad, Motaz, Emily Maggioli, Helder Leite y Hugo Martins. "Communication Requirements for a Hybrid VSC Based HVDC/AC Transmission Networks State Estimation". Energies 14, n.º 4 (19 de febrero de 2021): 1087. http://dx.doi.org/10.3390/en14041087.

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The communication infrastructure of the modern Supervisory, Control and Data Acquisition (SCADA) system continues to enlarge, as hybrid High Voltage Direct Current (HVDC)/Alternating Current (AC) networks emerge. A centralized SCADA faces challenges to meet the time requirements of the two different power networks topologies, such as employing the SCADA toolboxes for both grids. This paper presents the modern communication infrastructure and the time requirements of a centralized SCADA for hybrid HVDC/AC network. In addition, a case study of a complete cycle for a unified Weighted Least Squares (WLS) state estimation is tested on a hybrid HVDC/AC transmission network, based on Voltage Source Converter (VSC). The cycle estimates the elapsed times from the sensors up to the SCADA side, including the data acquisition and the WLS processing times. The case study is carried out on the Cigre B4 DC test case network with 43 virtual Remote Terminal Unit (RTU)s installed and 10 data concentrators, all connected through a fiber-based communication network. It is concluded that the time requirements can be fulfilled for a hybrid HVDC/AC network.

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Marykyn, Aleksander y Vasiliy Myroshenko. "The analysis of electromagnetic processes in reactive power compensation unit with variable inductance". Proceedings of Petersburg Transport University, n.º 2 (20 de junio de 2017): 298–306. http://dx.doi.org/10.20295/1815-588x-2017-2-298-306.

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Objective: To analyze transient processes when activating reactive power compensation unit with variable inductance and load bounce in electric traction alternating current network. To determine reactive power control range for possible structural variations of a unit. To choose the most power efficient variant of mutual connection of controlled reactor and capacitor bank with uncontrolled capacity in reactive power compensation unit. To make a conclusion, concerning feedback device application in control system. Methods: Connection diagrams of a unit to an alternating current monophase network. Mutual connection diagrams of controlled reactor and capacitor bank were chosen. Structural variations’ control range analysis of reactive power compensation unit was conducted. In MATLAB Simulink software package, simulation of different bucking out system circuitry was fulfilled. Simulation of compensation unit functioning was carried out for one variant with load bounce in electric traction. Results: It was established that, in case of series connection of controlled reactor and capacitor bank, control range may comprise no more than 15 % of nominal capacity. Starting current of a unit reaches twofold value. Parallel connection makes it possible to control reactive power in a broad band. Starting current in this case reaches fourfold excess of value. It is suggested to use uncontrolled reactor successively with capacitor bank as an additional unit. Such a variant makes it possible to reduce starting current and simultaneously provide filtration of the third current harmonics. Practical importance: A series-parallel variant of compensation unit circuitry seems to be the most perspective for application in electric traction alternating current network.

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Ayachi, B., T. Boukra y N. Mezhoud. "Multi-objective optimal power flow considering the multi-terminal direct current". Electrical Engineering & Electromechanics, n.º 1 (23 de febrero de 2021): 60–66. http://dx.doi.org/10.20998/2074-272x.2021.1.09.

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Introduction. In recent years, transmission systems comprise more direct current structures; their effects on alternating current power system may become significant and important. Also, multi-terminal direct current is favorable to the integration of large wind and solar power plants with a very beneficial ecological effect. The novelty of the proposed work consists in the effects of the aforementioned modern devices on transient stability, thus turn out to be an interesting research issue. In our view, they constitute a new challenge and an additional complexity for studying the dynamic behavior of modern electrical systems. Purpose. We sought a resolution to the problem of the transient stability constrained optimal power flow in the alternating current / direct current meshed networks. Convergence to security optimal power flow has been globally achieved. Methods. The solution of the problem was carried out in MATLAB environment, by an iterative combinatorial approach between optimized power flow computation and dynamic simulation. Results. A new transient stability constrained optimal power flow approach considering multi-terminal direct current systems can improve the transient stability after a contingency occurrence and operate the system economically within the system physical bounds. Practical value. The effectiveness and robustness of the proposed method is tested on the modified IEEE 14-bus test system with multi-objective optimization problem that reflect active power generation cost minimization and stability of the networks. It should be mentioned that active power losses are small in meshed networks relative to the standard network. The meshed networks led to a gain up to 46,214 % from the base case.

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Rosales Muñoz, Andrés Alfonso, Luis Fernando Grisales-Noreña, Jhon Montano, Oscar Danilo Montoya y Alberto-Jesus Perea-Moreno. "Application of the Multiverse Optimization Method to Solve the Optimal Power Flow Problem in Alternating Current Networks". Electronics 11, n.º 8 (18 de abril de 2022): 1287. http://dx.doi.org/10.3390/electronics11081287.

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In this paper, we solve the optimal power flow problem in alternating current networks to reduce power losses. For that purpose, we propose a master–slave methodology that combines the multiverse optimization algorithm (master stage) and the power flow method for alternating current networks based on successive approximation (slave stage). The master stage determines the level of active power to be injected by each distributed generator in the network, and the slave stage evaluates the impact of the proposed solution on each distributed generator in terms of the objective function and the constraints. For the simulations, we used the 10-, 33-, and 69-node radial test systems and the 10-node mesh test system with three levels of distributed generation penetration: 20%, 40%, and 60% of the power provided by the slack generator in a scenario without DGs. In order to validate the robustness and convergence of the proposed optimization algorithm, we compared it with four other optimization methods that have been reported in the specialized literature to solve the problem addressed here: Particle Swarm Optimization, the Continuous Genetic Algorithm, the Black Hole Optimization algorithm, and the Ant Lion Optimization algorithm. The results obtained demonstrate that the proposed master–slave methodology can find the best solution (in terms of power loss reduction, repeatability, and technical conditions) for networks of any size while offering excellent performance in terms of computation time.

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Agunov, A. V., A. T. Burkov y M. A. Ivanov. "Model of the traction and external power supply system joint operation". Journal of Physics: Conference Series 2131, n.º 4 (1 de diciembre de 2021): 042093. http://dx.doi.org/10.1088/1742-6596/2131/4/042093.

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Abstract The paper presents a description of mathematical model designed to study the joint operation of 25 kV alternating current traction power supply systems and 110 - 750 kV power supply systemsThe design concept of three-phase and single-phase PU-generators on the basis of the EMF source behind inductive resistance as well as three-phase and single-phase loads is considered. Based on the above mathematical expressions, a computer model has been developed to analyze the joint operation of three-phase networks of external power supply and single-phase traction networks. The model is implemented in the software package MATLAB -Simulink. Using this computer model the influence of power overflows in the 110 - 330 kV network of PJSC “Karelenergo” and PJSC “FGC UES” on the equalizing currents in the traction network of the Knyazhaya-Idel’ section of the October railroad was analyzed. Brief analysis of modeling results is presented.

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29

Radecke, Jan-Ole, Marina Fiene, Jonas Misselhorn, Carsten H. Wolters, Rebekka Lencer y Till R. Schneider. "Personalized transcranial alternating current stimulation targeting the dorsal attention network specifically modulates visuo-spatial attention". Brain Stimulation 16, n.º 1 (enero de 2023): 282. http://dx.doi.org/10.1016/j.brs.2023.01.490.

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30

Shevlyugin, Maxim, Andrey Kulikov y Darya Semenova. "Reduction of Economic Losses in the Contact Network and Overhead Lines Electrified with Alternating Current". Proceedings of Petersburg Transport University 20, n.º 4 (17 de diciembre de 2023): 975–86. http://dx.doi.org/10.20295/1815-588x-2023-4-975-986.

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Purpose: To reduce economic losses in the contact network (CN) and overhead lines (OL) electrified with alternating current. The existing electromagnetic influences on the alternating current railway lead to significant economic losses. Additionally, there is a problem of the contact wire (CW) burnout during the passage of a neutral section with a raised pantograph under voltage on a high-speed railway line (HSRL). CW burnout leads to failure of the contact network, repair costs, possible damage to other people’s property and rolling stock. As a whole, all this represents significant economic losses. Methods: The analysis of material and time costs for the elimination of problems that arise due to the CW burnout or due to the use of manual labor during the installation of OL has been carried out, in comparison with the proposed solutions to reduce economic losses. Results: In solving the problem of the negative electromagnetic influence of the contact line (CL) on the OL, a mobile mechanized complex (MMC) is designed to help, which performs the transposition of the OL wires in 6 steps with scrolling by 60° each support. This method will allow us to place the OL wires equidistantly from the contact wire. Scrolling with once-per-support frequency will align the asymmetry of the linear electrical parameters. All in all, MMC performs installation in an automated mode. The problems of the CW burnout can be reduced by the insulating coupling device (ICD) of the CL. ICD CL is a set of step resistances, which are located at the outer sections of the phase wires before and after the neutral section. It is aimed at reducing the current to a safe value, which will not lead to the contact wire burnout, failure of the CN and/or rolling stock and possible damage to other people’s property. Practical significance: The result is a set of measures in the form of MMC to reduce economic losses in overhead lines from the influence of CN and ICD CL to reduce losses in the contact network by maintaining the operability of the contact wire.

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31

Tryapkin, Evgeniy Yuryevich, Ivan Vladimirovich Ignatenko, Sergey Anatolyevich Vlasenko y Natalya Konstantinovna Shurova. "Study of causes of increased potentials of alternating current traction rail network by registration of data in united time mode". Transport of the Urals, n.º 1 (2023): 120–25. http://dx.doi.org/10.20291/1815-9400-2023-1-120-125.

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The paper considers results of straight instrumental study of rail line parameters in conditions of operating section of traction network that allow assessing influence of non-sinusoidality and current value on the process of creation of «rail - ground» potential. The paper presents a formula for a particular case of calculation of voltage form on a rail line section. As a result, this function may be an element of calculation of electrical processes in 25kV alternating current back rail network.

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32

Kolesnichenko, I. E., E. A. Kolesnichenko, E. I. Lyubomishchenko y E. I. Kolesnichenko. "Alternating electric current in coal mines: electromagnetic energy and its conversion into electric current". Mining Industry Journal (Gornay Promishlennost), n.º 6/2023 (25 de diciembre de 2023): 128–36. http://dx.doi.org/10.30686/1609-9192-2023-6-128-136.

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The article addresses the challenge of improving the competence and basic knowledge of specialists working with alternating electric current. The purpose of this work is to explain the magnetic properties of substance, generation of magnetic field and electric current with due account for the known laws of physics and the Quantum theory. We believe that addressing these tasks needs to begin with the energy produced by the magnet. The method of inducing electric energy using magnetic field of a permanent magnet is chosen as the research subject. The historical mythological bases of interpreting the induction of electric energy are shown. Modern instruments prove that the magnetic field is the electromagnetic emissions of magnets. A hypothesis regarding the origin of magnetic properties of substance is developed based on analysis of the known magnetic properties of alpha-iron. Two features of the magnetic properties of substance have been revealed, which differ from Ampere's ideas. The first is the local volume of atoms combined by short-acting covalent bonds, forming a natural crystalline or artificially elongated structure. The second is that the frequency of electromagnetic emissions by the valence electrons of all the atoms in Hertz is approximately the same. The total radiation of energy by all the atoms in local formations generates a magnetic field. The hypothesis is confirmed by circuits and information on instruments that measure the emission of magnets in Hertz. When the energy absorbed by electrons increases, the bond between atoms is broken and magnetic emissions cease. All substances in liquid and solid aggregate state begin to radiate electromagnetic emissions to other substances under the impact of external electromagnetic emissions. This is confirmed by photographic evidence of the performed experiments. A hypothesis is proposed, which differs from the ideas about the movement of free electrons by the fact that the formation of electric current is the result of absorbing electromagnetic emissions of the magnet by valence electrons of the electrical conductor and their transfer into the electric network. The physical phenomena of energy transfer between the transformer windings in an electric circuit prove that electric current is a concentrated flow of electromagnetic emissions, which are a wave form of energy.

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33

Georgilakis, Pavlos S. y Peter G. Vernados. "Flexible AC Transmission System Controllers: An Evaluation". Materials Science Forum 670 (diciembre de 2010): 399–406. http://dx.doi.org/10.4028/www.scientific.net/msf.670.399.

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Electricity market activities and a growing demand for electricity have led to heavily stressed power systems. This requires operation of the networks closer to their stability limits. Cost effective solutions are preferred over network extensions. The flexible alternating current transmission system (FACTS), a new technology based on power electronics, offers an opportunity to enhance controllability, stability, and power transfer capability of ac transmission systems. This paper provides a comprehensive review and evaluation of FACTS controllers.

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34

Kamarudin, Nazhatul Hafizah, Mohammad Arif Ilyas, Saidatul Izyanie Kamarudin y Marizuana Mat Daud. "DEPLOYMENT OF SENSOR NETWORKS FOR EFFICIENT POWER CONSUMPTION MONITORING APPLICATION". Journal of Information System and Technology Management 8, n.º 33 (10 de diciembre de 2023): 127–38. http://dx.doi.org/10.35631/jistm.833011.

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This paper presents a wireless monitoring system implemented using a wireless sensor network and the XCTU software. The existing monitoring systems for tracking alternating current utilization in various devices face limitations in terms of real-time data acquisition and seamless wireless transmission to a central computer for comprehensive analysis. This hinders the ability to accurately measure electric current consumption, impeding the development of efficient energy management strategies. Therefore, the primary focus of this monitoring system is to wirelessly track the utilization of alternating current in various devices. The wireless monitoring system relies on the integration of the XBEE device and the SCT 013 current sensor. The SCT 013 current sensor accurately measures electric current consumption, exhibiting a mere 0.03 variation, while the XBEE device is employed to transmit this data wirelessly to a computer for subsequent data analysis. In this configuration, the XBEE operates in AT mode for seamless data transfer to the computer.

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35

Ndlela, Nomihla Wandile y Innocent Ewean Davidson. "Network Coordination between High-Voltage DC and High-Voltage AC Transmission Systems Using Flexible AC Transmission System Controllers". Energies 15, n.º 19 (9 de octubre de 2022): 7402. http://dx.doi.org/10.3390/en15197402.

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The strategic intent of the African Union is to develop a “Smart Integrated African Electric Power Super Grid” driven by modern tools and advances in high-voltage direct current (HVDC) engineering and flexible alternating current technology systems (FACTS), which is central in supporting Africa’s sustained economic growth and development. The southern African region, including South Africa, is beset by the critical challenges of perennial load-shedding, which impedes economic growth and aggravates unemployment. This has led to the insecurity of electricity supplies and degraded the quality of life. The parallel operation of high-voltage direct current (HVDC) and flexible AC technology systems (FACTS) controllers is gaining traction as system conditions become more complex, such as weak power networks which requires increased stability requirements, resulting in load-shedding and power outages. These adversely affect business productivity and adversely affect GDP and economic growth. Thus, the application of innovative technologies such as HVDC links can stabilize weak power systems. It is established that HVDC delivery systems reduce losses in long transmission lines transporting bulk power compared with high-voltage alternating current (HVAC) transmission lines for power wheeling. This paper evaluates the parallel operation of the Cahora Bassa 1414 km bipolar HVDC link and a weak parallel 400/330 kV alternating current (AC) link. It demonstrates the use of FACTS controllers to enhance the technical performance of an existing network, such as voltage control, and technical loss reduction. It combines an HVDC line commutated converter (LCC) and HVAC transmission lines, in hybrid notation to increase the voltage stability of the system by controlling the reactive power with a Static Var Compensator (SVC). These modern tools can increase the transmission power controllability and stability of the power network. In this study, HVDC–LCC was used with a setpoint of 1000 MW in conjunction with the 850 MVAr SVC. The results show that the technical losses were reduced by 0.24% from 84.32 MW to 60.32 MW as Apollo 275 kV SVC was utilized for voltage control. The network analysis was performed using DIgSILENT PowerFactory software that is manufactured by DIgSILENT GmbH at Gomaringen, Germany

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36

Kosarev, A. B. y B. I. Kosarev. "Calculation methodology of current distribution in traction networks of AC current". Vestnik of the Railway Research Institute 76, n.º 6 (28 de diciembre de 2017): 329–35. http://dx.doi.org/10.21780/2223-9731-2017-76-6-329-335.

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Several publications have been devoted to the development of traction power supply for alternating current [1, 2]. They set the task of considering the resistance of the external power supply system and power traction transformers when calculating the current distribution in traction networks. With all the merits of the existing methods for calculating these resistances, there are discrepancies in the published sources in determining the parameters of the equivalent circuit for the traction power supply system [3, 4, 5, 6]. In the present work, the authors propose a technique for calculating reduced to a voltage of 27.5 kV equivalent resistances of an external power supply system and a power traction transformer. An equivalent circuit for replacing the traction power supply system is substantiated, allowing to take into account the voltage drop on the overall resistance of the external power supply system from the traction currents of the considered and adjacent feeder zones, as well as transit currents flowing through the power lines. Using the method of symmetrical components it was obtained that when calculating the internal resistance of a traction substation consisting of the resistances of the longitudinal power supply line and the power traction transformer, it is necessary to use the calculated formulas obtained when taking into account the actual current distribution in the secondary (traction) winding of the power traction transformer. It is shown that the traction network equivalent circuit for the calculation of short-circuit currents, given in [1, 2], does not reflect the real current distribution relationships in traction networks. The main reason for the inconsistency of the scheme proposed by a number of experts with the existing traction power supply system is determined by an unjustified transition from an asymmetric system “three-phase transmission line - transformer - power supply system - single-phase traction network” to a single-line calculation scheme. When calculating the current distribution according to this scheme, there is no metallic connection of the track with one of the phases (more often phase C ) of the power traction transformer. The absence of this connection leads to the flow of traction currents between the district and traction substations, short-circuit current on the ground, which is not permissible.

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37

Pan, Hao, Ming Ding, Rui Bi y Lei Sun. "Research on Cooperative Planning of Distributed Generation Access to AC/DC Distribution (Micro) Grids Based on Analytical Target Cascading". Energies 12, n.º 10 (15 de mayo de 2019): 1847. http://dx.doi.org/10.3390/en12101847.

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With the wide application of distributed generation (DG) and the rapid development of alternating current/direct current (AC/DC) hybrid microgrids, the optimal planning of distributed generation connecting to AC/DC distribution networks/microgrids has become an urgent problem to resolve. This paper presents a collaborative planning method for distributed generation access to AC/DC distribution (micro) grids. Based on the grid structure of the AC/DC distribution network, the typical interconnection structure of the AC/DC hybrid microgrid and AC/DC distribution network is designed. The optimal allocation models of distributed power supply for the AC/DC distribution network and microgrid are established based on analytical target cascading. The power interaction between the distribution network and microgrid is used to establish a coupling relationship, and the augmented Lagrangian penalty function is used to solve the collaborative programming problem. The results of distributed power supply allocation are obtained, solving the problem so that distribution generation with different capacity levels is connected to the power grid system in a single form.

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38

Ouyang, Junfeng y Changchun Chi. "The Prediction of Residual Electrical Life in Alternating Current Circuit Breakers Based on Savitzky-Golay-Long Short-Term". Sensors 23, n.º 15 (1 de agosto de 2023): 6860. http://dx.doi.org/10.3390/s23156860.

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In order to improve the accuracy of predicting the remaining electrical life of AC circuit breakers, ensure the safe operation of electrical equipment, and reduce economic losses caused by equipment failures, this paper studies a method based on the Savitzky–Golay convolution smoothing long short-term memory neural network for predicting the electrical life of AC circuit breakers. First, a full lifespan test is conducted to obtain degradation data throughout the entire life cycle of the AC circuit breaker, from which feature parameters that effectively reflect its operational state are extracted. Next, principal component analysis and the maximum information coefficient are used to remove redundancy in the feature parameters and choose the best subset of features. Subsequently, the Savitzky–Golay convolutional smoothing algorithm is employed to smooth the feature sequence, reducing the impact of noise and outliers on the feature sequence while preserving its main trends. Then, a secondary feature extraction is performed on the smoothed feature subset to obtain the optimal secondary feature subset. Finally, the remaining electrical lifespan of the AC circuit breaker is treated as a long-term sequence problem and the long short-term memory neural network method is used for precise time-series forecasting. The proposed model outperforms backpropagation neural networks and the gate recurrent unit in terms of prediction precision, achieving an impressive 97.4% accuracy. This demonstrates the feasibility of using time-series forecasting for predicting the residual electrical lifespan of electrical equipment and provides a reference for optimizing the method of predicting remaining electrical life.

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Myatezh, S. V., M. V. Novolodskiy, E. T. Kitova, V. Y. Konyukhov y I. M. Daudov. "Presentation of distortion power in an alternating current network and analysis of factors of its occurrence". Journal of Physics: Conference Series 1384 (noviembre de 2019): 012074. http://dx.doi.org/10.1088/1742-6596/1384/1/012074.

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40

Toloza, Enrique H. S., Ehsan Negahbani y Flavio Fröhlich. "Ih interacts with somato-dendritic structure to determine frequency response to weak alternating electric field stimulation". Journal of Neurophysiology 119, n.º 3 (1 de marzo de 2018): 1029–36. http://dx.doi.org/10.1152/jn.00541.2017.

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Transcranial current stimulation (tCS) modulates brain dynamics using weak electric fields. Given the pathological changes in brain network oscillations in neurological and psychiatric illnesses, using alternating electric field waveforms that engage rhythmic activity has been proposed as a targeted, network-level treatment approach. Previous studies have investigated the effects of electric fields at the neuronal level. However, the biophysical basis of the cellular response to electric fields has remained limited. Here, we characterized the frequency-dependent response of different compartments in a layer V pyramidal neuron to exogenous electric fields to dissect the relative contributions of voltage-gated ion channels and neuronal morphology. Hyperpolarization-activated cation current (Ih) in the distal dendrites was the primary ionic mechanism shaping the model’s response to electric field stimulation and caused subthreshold resonance in the tuft at 20 ± 4 Hz. In contrast, subthreshold Ih-mediated resonance in response to local sinusoidal current injection was present in all model compartments at 11 ± 2 Hz. The frequencies of both resonance responses were modulated by Ih conductance density. We found that the difference in resonance frequency between the two stimulation types can be explained by the fact that exogenous electric fields simultaneously polarize the membrane potentials at the distal ends of the neuron (relative to field direction) in opposite directions. Our results highlight the role of Ih in shaping the cellular response to electric field stimulation and suggest that the common model of tCS as a weak somatic current injection fails to capture the cellular effects of electric field stimulation. NEW & NOTEWORTHY Modulation of cortical oscillation by brain stimulation serves as a tool to understand the causal role of network oscillations in behavior and is a potential treatment modality that engages impaired network oscillations in disorders of the central nervous system. To develop targeted stimulation paradigms, cellular-level effects must be understood. We demonstrate that hyperpolarization-activated cation current (Ih) and cell morphology cooperatively shape the response to applied alternating electric fields.

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Kar, Kohitij, Takuya Ito, Michael W. Cole y Bart Krekelberg. "Transcranial alternating current stimulation attenuates BOLD adaptation and increases functional connectivity". Journal of Neurophysiology 123, n.º 1 (1 de enero de 2020): 428–38. http://dx.doi.org/10.1152/jn.00376.2019.

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Transcranial alternating current stimulation (tACS) is used as a noninvasive tool for cognitive enhancement and clinical applications. The physiological effects of tACS, however, are complex and poorly understood. Most studies of tACS focus on its ability to entrain brain oscillations, but our behavioral results in humans and extracellular recordings in nonhuman primates support the view that tACS at 10 Hz also affects brain function by reducing sensory adaptation. Our primary goal in the present study is to test this hypothesis using blood oxygen level-dependent (BOLD) imaging in human subjects. Using concurrent functional magnetic resonance imaging (fMRI) and tACS, and a motion adaptation paradigm developed to quantify BOLD adaptation, we show that tACS significantly attenuates adaptation in the human motion area (hMT+). In addition, an exploratory analysis shows that tACS increases functional connectivity of the stimulated hMT+ with the rest of the brain and the dorsal attention network in particular. Based on field estimates from individualized head models, we relate these changes to the strength of tACS-induced electric fields. Specifically, we report that functional connectivity (between hMT+ and any other region of interest) increases in proportion to the field strength in the region of interest. These findings add support for the claim that weak 10-Hz currents applied to the scalp modulate both local and global measures of brain activity. NEW & NOTEWORTHY Concurrent transcranial alternating current stimulation (tACS) and functional MRI show that tACS affects the human brain by attenuating adaptation and increasing functional connectivity in a dose-dependent manner. This work is important for our basic understanding of what tACS does, but also for therapeutic applications, which need insight into the full range of ways in which tACS affects the brain.

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42

Yan, Xin, Jia Gen Du y Jun Ru Li. "The Digital Watermarking Used to the Smart Power Grid Security". Advanced Materials Research 181-182 (enero de 2011): 770–75. http://dx.doi.org/10.4028/www.scientific.net/amr.181-182.770.

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The communication networks used to smart power grid include wired and wireless networks in terms of data transmission mode, and wireless networks mainly refer to wireless sensor networks (WSN). Accordingly, the data security in smart power grid involves the data transmission security in both cable networks and WSN. WSN is an application-specific network, and a promising research in smart power grid field. In this paper, we use the digital watermarking technology to solve WSN security in smart power grid. Firstly we propose a watermark mechanism based on alternating current, including watermark generation, embedding and detection algorithms. And then we use simulation results to demonstrate its feasibility and efficiency.

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43

Jin, Ming, Wenwei Li, Yuefeng Ma, Haoyu Zeng, Minghui Huang, Chao Lu y Guo Yang. "Investigation on the Electrical Conductivity of Graphene/Cement Composites by Alternating Current Method". Materials 16, n.º 4 (8 de febrero de 2023): 1436. http://dx.doi.org/10.3390/ma16041436.

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This paper is concerned with an analysis of the electrical conductivity of graphene/cement composites by means of DC (direct current) and AC (alternating current) techniques. Moreover, the micrograph and element composition of composites have been characterized through SEM (scanning electron microscopy) and EDS (energy-dispersive spectrometers) techniques, respectively. Results revealed that a percolation transition region Φ2–Φ1 (Φ2 and Φ1 values are determined as 0.8% and 1.8%, respectively) can be observed in the S-shaped curve. In addition, the logistic model has been recommended to characterize the relationship between the conductivity and the graphene concentration, which ranged from 0.001% to 2.5%. The micrographs obtained by SEM technique clearly indicate a complete conductive network as well as agglomeration of graphene slices when the graphene content reaches the threshold value. Furthermore, graphene slices can be distinguished from the cement hydration products by means of the analysis of element composition obtained through the EDS technique. It is promising to apply the graphene/cement composites as intelligent materials.

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44

Belkhiri, S., M. Bouroubi y A. Harrabi. "Improvement of the Transient Stability of a 14-bus Network Using a Superconducting Fault-Current Limiter SFCL". Advanced Electromagnetics 9, n.º 2 (21 de octubre de 2020): 75–83. http://dx.doi.org/10.7716/aem.v9i2.1450.

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This study presents a new strategy for implementing the superconducting fault current limiter SFCL in order not only to limit short - circuit currents but also to improve the stability of electrical networks in the presence of faults. The calculation of the impedance that the limiter must introduce into the test network at the moment of the failure is obtained from a three-dimensional computation code, developed and implemented under MATLAB environment where the formulation in magnetic vector potentials A and scalar potential Electric V is adopted to solve the electromagnetic problem and the heat diffusion formulation is adopted also to solve the thermal problem. The coupling is ensured by an alternating algorithm and the numerical resolution of the problem is ensured by the method of the finite volumes in its three-dimensional version in order to avoid certain problems of numerical convergence linked to the strongly nonlinear character of the problem to be solved. The modeling of the network tests will be made by PSAT under the environment MATLAB.

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45

Tobin, Anne-Elise y Ronald L. Calabrese. "Myomodulin Increases Ih and Inhibits the Na/K Pump to Modulate Bursting in Leech Heart Interneurons". Journal of Neurophysiology 94, n.º 6 (diciembre de 2005): 3938–50. http://dx.doi.org/10.1152/jn.00340.2005.

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In the medicinal leech, a rhythmically active 14-interneuron network composes the central pattern generator for heartbeat. In two segmental ganglia, bilateral pairs of reciprocally inhibitory heart interneurons (oscillator interneurons) produce a rhythm of alternating bursts of action potentials that paces activity in the pattern-generating network. The neuropeptide myomodulin decreases the period of this bursting and increases the intraburst spike frequency when applied to isolated ganglia containing these oscillator interneurons. Myomodulin also decreases period, increases spike frequency, and increases the robustness of endogenous bursting in synaptically isolated (with bicuculline) oscillator interneurons. In voltage-clamp experiments using hyperpolarizing ramps, we identify an increase in membrane conductance elicited by myomodulin with the properties of a hyperpolarization-activated current. Voltage steps confirm that myomodulin indeed increases the maximum conductance of the hyperpolarization-activated current Ih. In similar experiments using Cs+ to block Ih, we demonstrate that myomodulin also causes a steady offset in the ramp current that is not associated with an increase in conductance. This current offset is blocked by ouabain, indicating that myomodulin inhibits the Na/K pump. In current-clamp experiments, when Ih is blocked with Cs+, myomodulin decreases period and increases spike frequency of alternating bursting in synaptically connected oscillator interneurons, suggesting that inhibiting the Na/K pump modulates these burst characteristics. These observations indicate that myomodulin decreases period and increases spike frequency of endogenous bursting in synaptically isolated oscillator heart interneurons and alternating bursting of reciprocally inhibitory pairs of interneurons, at least in part, by increasing Ih and by decreasing the Na/K pump.

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46

Lewicki, Wojciech, Mariusz Niekurzak y Ewelina Sendek-Matysiak. "Electromobility Stage in the Energy Transition Policy—Economic Dimension Analysis of Charging Costs of Electric Vehicles". Energies 17, n.º 8 (18 de abril de 2024): 1934. http://dx.doi.org/10.3390/en17081934.

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The available literature emphasizes that by 2040, electric vehicles may constitute up to 50% of the fleet of all passenger vehicles. This process will be one of the elements of the energy transformation and, at the same time, consistent with the idea of sustainable transport. As part of this research, the actual energy consumption and the range of electric vehicles were determined. This research was carried out using a selected group of electric cars from the most popular segments of passenger cars. The calculations were based on three charging scenarios: a home electrical network, a public alternating current (AC) charging station that allows charging with single-phase alternating current or alternating current, and a public direct current (DC) charging station that allows charging with direct current. The obtained results were compared with the results of cars with internal combustion and diesel engines after driving a 100-kilometer section of the route. In a broader scope, this research addresses the entities responsible for the energy transformation and the electromobility development strategy. In a narrower sense, vehicle users are considering the purchase of this type of vehicle for political, economic and technological reasons.

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47

Tambunan, Handrea Bernando, Nur Widi Priambodo, Joko Hartono, Indra Ardhanayudha Aditya, Meiri Triani y Rasgianti Rasgianti. "Research trends on microgrid systems: a bibliometric network analysis". International Journal of Electrical and Computer Engineering (IJECE) 13, n.º 3 (1 de junio de 2023): 2529. http://dx.doi.org/10.11591/ijece.v13i3.pp2529-2545.

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<span lang="EN-US">The numeral of academic publications in the microgrid system field has rapidly grown. A microgrid system is a group of interconnected distributed generation, loads, and energy storage operating as a single controllable entity. Many published articles recently focused on distributed generation, system control, system stability, power quality, architectures, and broader focus areas. This work analyzes microgrid: alternating current (AC), direct current (DC), and hybrid AC/DC microgrid systems with bibliometric network analysis through descriptive analysis, authors analysis, sources analysis, words analysis, and evolutionary path based on the Scopus database between 2010 and 2021. The finding helps find out the top authors and most impact sources, most relevant and frequently used in the research title, abstract, and keyword, graphically mapping the research evolved and identifying trend topic.</span>

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48

Xu, Ang, Xiaoxiao Shi, Yufeng Zhou, Kai Guo, Haibin Shi y Yong Shi. "Simulation Research on Tightening Force and Temperature Distribution of Tension Clamps in Distribution Network". Journal of Physics: Conference Series 2401, n.º 1 (1 de diciembre de 2022): 012094. http://dx.doi.org/10.1088/1742-6596/2401/1/012094.

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Abstract In order to study the effect of tightening torque on the temperature change of overhead line tension clamps and conductors, a structural model of NLL-4 tension clamps was established using COMSOL Multiphysics. Under the power frequency of 400-650A, the electromagnetic-thermal coupling finite element simulation analysis of the tension clamp was carried out by adjusting the tightening torque, and the three-dimensional temperature field distribution of the tension clamp and the wire was obtained. The results show that when 600A power frequency alternating current is applied, the tightening torque decreases continuously, and the overall temperature of the tension clamp and wire increases with the decrease of the torque. When the tightening torque is constant, different power frequency AC currents of 400-650A are applied, and the overall temperature of the tension clamp increases with the increase of the current; at the same time, no matter how the current and tightening torque change, the temperature of the extrusion part of the wire is always higher than the temperature of the unextruded part.

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49

Xie, Jianwen, Ruiqi Gao, Zilong Zheng, Song-Chun Zhu y Ying Nian Wu. "Learning Dynamic Generator Model by Alternating Back-Propagation through Time". Proceedings of the AAAI Conference on Artificial Intelligence 33 (17 de julio de 2019): 5498–507. http://dx.doi.org/10.1609/aaai.v33i01.33015498.

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This paper studies the dynamic generator model for spatialtemporal processes such as dynamic textures and action sequences in video data. In this model, each time frame of the video sequence is generated by a generator model, which is a non-linear transformation of a latent state vector, where the non-linear transformation is parametrized by a top-down neural network. The sequence of latent state vectors follows a non-linear auto-regressive model, where the state vector of the next frame is a non-linear transformation of the state vector of the current frame as well as an independent noise vector that provides randomness in the transition. The non-linear transformation of this transition model can be parametrized by a feedforward neural network. We show that this model can be learned by an alternating back-propagation through time algorithm that iteratively samples the noise vectors and updates the parameters in the transition model and the generator model. We show that our training method can learn realistic models for dynamic textures and action patterns.

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50

Qi, Xiaomin, Wei Pei, Luyang Li y Li Kong. "A Fast DC Fault Detection Method for Multi-Terminal AC/DC Hybrid Distribution Network Based on Voltage Change Rate of DC Current-Limiting Inductor". Energies 11, n.º 7 (12 de julio de 2018): 1828. http://dx.doi.org/10.3390/en11071828.

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The rapid detection of direct current (DC) faults is one of the key technologies for the development of multi-terminal alternating current (AC)/DC hybrid distribution networks. The DC fault current rises quickly and affects the whole network. Therefore, DC faults must be detected much faster than AC faults. This paper proposes a fast DC fault detection method based on the voltage change rate of the current-limiting inductor (CLI) for the multi-terminal AC/DC hybrid distribution network. Firstly, the characteristics of the fault voltages and currents and of the CLIs are studied in detail, and the feasibility of using the voltage change rate of the CLI to detect DC fault is analyzed. Based on this, a primary fault detection method is proposed to identify the faulty line, determine the fault type and the fault poles using the amplitudes of the single-ended CLI voltage change rates. For high-resistance DC faults, a backup detection method using the directions and amplitudes of the voltage change rates of the double-ended CLIs is proposed. Finally, the proposed method is verified by MATLAB simulations. The simulation results show that the proposed method can detect all DC faults accurately, and the faulty line, fault type and fault poles can be determined quickly. The proposed method is not affected by the fault location, current-limiting inductance, power reversal of the converters, AC fault and communication delay.

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