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1
Brzhezitsky, V. O., Y. O. Haran, A. O. Derzhuk, O. R. Protsenko, Y. O. Trotsenko und M. M. Dixit. „Ultimate effect of non-identity of capacitive elements of high-voltage arm on frequency characteristics of voltage divider (analytical research)“. Electrical Engineering & Electromechanics, Nr. 4 (29.07.2021): 46–52. http://dx.doi.org/10.20998/2074-272x.2021.4.06.
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Purpose. Determination in the analytical form of the maximum limiting influence of the non-identity of the capacitive elements of the high-voltage arm on the amplitude-frequency characteristic and phase-frequency characteristic of the voltage divider with parallel-series connection of R-, C-elements of the high-voltage arm. Methodology. Based on the previously developed theory of broadband voltage dividers with parallel-series connection of R-, C-elements, analytical expressions for amplitude-frequency and phase-frequency characteristics of the voltage divider are obtained and investigated taking into account the limit case of non-identical capacitive elements of high-voltage arm. Results. The nature of the dependencies of the frequency characteristics of the broadband voltage divider on the value of the tolerance of the capacitive elements of the high-voltage arm, the division factor of the voltage divider in a wide range of frequency changes is determined. Simplified approximating expressions for the maximum values of frequency characteristics of the voltage divider are proposed and their error is determined. Originality. For the first time in the analytical form the limiting influence of non-identity of capacitive elements of a high-voltage arm of a voltage divider on its frequency characteristics is considered. A mathematical model of this influence is constructed and the limit values of frequency characteristics of the voltage divider are determined. Practical value. It is recommended to introduce into the normative documentation of broadband voltage dividers the corrected value of the division factor, which allows to significantly reduce the deviation of the actual value of the division factor of the voltage divider from the normalized value in a wide range of frequency changes.
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Satriyadi, I. Gusti Ngurah, I. Made Yulistya Negara, Daniar Fahmi, N. Wijayanto, Mochammad Wahyudi, Dimas Anton Asfani und Adi Soeprijanto. „Ferroresonance Characteristics on Capacitive Voltage Transformer Under Lightning Impulse Voltage“. International Review on Modelling and Simulations (IREMOS) 9, Nr. 4 (31.08.2016): 306. http://dx.doi.org/10.15866/iremos.v9i4.9273.
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3
Pawawoi, Andi, und Syafii Syafii. „On Load Characteristic of the New Design Permanent Magnets Reluctance Generator“. International Journal of Applied Power Engineering (IJAPE) 6, Nr. 3 (01.12.2017): 193. http://dx.doi.org/10.11591/ijape.v6.i3.pp193-198.
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These The new design of a permanent magnet reluctance generator claimed to be able to convert the energy of the permanent magnet is the source of the main field into electrical energy, so that the generator output power can reach 167% compared with the input power axis. In this paper will discuss the characteristics of the generator voltage when under load, pure resistance, inductive load and caThese The new design of a permanent magnet reluctance generator claimed to be able to convert the energy of the permanent magnet is the source of the main field into electrical energy, so that the generator output power can reach 167% compared with the input power axis. In this paper will discuss the characteristics of the generator voltage when under load, pure resistance, inductive load and capacitive load. The results showed that when given a purely resistive load, the terminal voltage tends to be constant, but if given the inductive load, the voltage drop occurs significantly approaching zero voltage at full load current. It is very different when loaded capacitive load. When the generator under load is capacitive, the generator voltage at full load increased by 224.7% from no-load voltage.pacitive load. The results showed that when given a purely resistive load, the terminal voltage tends to be constant, but if given the inductive load, the voltage drop occurs significantly approaching zero voltage at full load current. It is very different when loaded capacitive load. When the generator under load is capacitive, the generator voltage at full load increased by 224.7% from no-load voltage
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Liu, Shoubao, Yucheng Hou, Zhonghao Xiong, Yuan Fang und Li Tong. „Study on Impact Response Characteristics of Capacitive Voltage Transformer“. Journal of Physics: Conference Series 1486 (April 2020): 062017. http://dx.doi.org/10.1088/1742-6596/1486/6/062017.
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5
Pawawoi, Andi, und Syafii Syafii. „On Load Characteristic of the New Design Permanent Magnets Reluctance Generator“. International Journal of Applied Power Engineering (IJAPE) 6, Nr. 3 (01.12.2017): 199. http://dx.doi.org/10.11591/ijape.v6.i3.pp199-204.
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These The new design of a permanent magnet reluctance generator claimed to be able to convert the energy of the permanent magnet is the source of the main field into electrical energy, so that the generator output power can reach 167% compared with the input power axis. In this paper will discuss the characteristics of the generator voltage when under load, pure resistance, inductive load and capacitive load. The results showed that when given a purely resistive load, the terminal voltage tends to be constant, but if given the inductive load, the voltage drop occurs significantly approaching zero voltage at full load current. It is very different when loaded capacitive load. When the generator under load is capacitive, the generator voltage at full load increased by 224.7% from no-load voltage
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Hrbac, Roman, Vaclav Kolar, Mikolaj Bartlomiejczyk, Tomas Mlcak, Petr Orsag und Jakub Vanc. „A Development of a Capacitive Voltage Divider for High Voltage Measurement as Part of a Combined Current and Voltage Sensor“. Elektronika ir Elektrotechnika 26, Nr. 4 (07.08.2020): 25–31. http://dx.doi.org/10.5755/j01.eie.26.4.25888.
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This article deals with the development of capacitive voltage divider for high voltage measurements and presents a method of analysis and optimization of its parameters. This divider is a part of a combined voltage and current sensor for measurements in high voltage power networks. The sensor allows continuous monitoring of the network distribution status and performs a quick diagnosis and location of possible network failures. Deployment of these devices will support semi-autonomous control of power networks and it can be considered as a step from traditional power grids toward smart grids. This is a worldwide trend connected with increasing number of renewable energy sources and plug-in electric vehicles as described in. In this way, it contributes to the reliability of the distribution network. Together with automated control techniques and fault location methods, it enables its self-healing capability. The following characteristics required for the sensor include: current measurement error up to 2 %, voltage measurement error up to 0.5 %, and power measurement error up to 5 %. At the same time, it is necessary that the sensor is cost-effective - relatively cheap. There were selected capacitors made in series production for the capacitive divider designing. The capacitive voltage divider was tested in terms of time and temperature stability; the results are described in the paper. Then, the method of mathematical correction of a temperature dependence of the capacitive voltage divider was suggested and tested.
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Liu, Shulin, und Yongxiu Zhao. „Research on Short-Circuit Discharge Characteristics of Capacitive Circuits Based on Safety Spark Test Apparatus“. Mathematical Problems in Engineering 2014 (2014): 1–9. http://dx.doi.org/10.1155/2014/516925.
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Based on the safety spark test apparatus, the short-circuit spark discharge (SCSD) characteristics of the simple capacitive circuit and switching converter are studied. It is pointed out that their SCSD process can be divided into four stages, that is, dielectric-breakdown stage, spark-generated stage, spark-maintenance stage, and spark-extinguish stage; moreover, there is different equivalent spark resistance in each stage. For the simple capacitive circuit, its spark resistance is larger and maintaining voltage is almost unchanged in the spark-maintenance stage. For the switching converter, its output short-circuit characteristics depend strongly on the load resistance and its maintaining voltage reduces rapidly with the decrease of the load resistance. The circuit model is proposed, which can simulate the output SCSD process of the switching converter. By using the least-squares method, the relationship expressions between the discharge duration and capacitance in each time-stage are derived and the corresponding equivalent resistance is obtained. The mathematical models are established, and the expressions of the discharge current and voltage are deduced. Experiment and simulation results are positive in the analysis showing the feasibility of the proposed models.
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Xu, Yunyang, Heng Nian, Yangming Wang und Dan Sun. „Impedance Modeling and Stability Analysis of VSG Controlled Grid-Connected Converters with Cascaded Inner Control Loop“. Energies 13, Nr. 19 (01.10.2020): 5114. http://dx.doi.org/10.3390/en13195114.
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This paper develops the impedance models of grid-connected converters under the virtual synchronous generator (VSG) strategy with a cascaded inner control loop and analyzes the system stability of VSG controlled converters with different kinds of weak grid. Different from existing small-signal models with high dimensions, a single-in-single-out (SISO) impedance model with simple mathematical expression is obtained in this paper, which is applied to identify the influence of the cascaded control loop on impedance characteristics and system stability. It is found that the impedance characteristics of VSG controlled converters can become capacitive below the fundamental frequency, and it is mainly caused by the voltage controller in the cascaded control loop of the VSG strategy. Impedance-based stability analysis shows that the capacitive impedance characteristics can benefit the compatibility of converters operated with the series-compensated weak grid, but may deteriorate the system stability with the inductive weak grid, which can be avoided by increasing the proportional coefficients of the cascaded voltage and current controllers or applying a larger virtual resistor to reduce the negative resistance in the capacitive frequency range. Experiments based on the control-hardware-in-loop (CHIL) platform were carried out to verify the developed analytical models and possible system instable cases.
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Nadtoka, Ivan, Pyotr Osadchiy und Vladimir Tropin. „Features of Application of the «Open Triangle» Scheme in the Rural Low-Voltage Structure Distribution Network“. Известия высших учебных заведений. Электромеханика 63, Nr. 5 (2020): 72–78. http://dx.doi.org/10.17213/0136-3360-2020-5-72-78.
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The features of applying the «open triangle» scheme in the structure of a rural low-voltage distribution network with a voltage of 220 V are studied from the standpoint of achieving a certain energy efficiency. The energy effect is estimated by the criterion of the relative value of the additional power losses in the conductors of a three-wire line of a 220 V network caused by reactive power and load asymmetry. The load is modeled by two power receivers connected to the phase-to-phase voltage, the general output of the power receivers is grounded, which forms the «open triangle» circuit. The energy characteristics of the active load, active load with capacitive corrective element, active load with capacitive and inductive corrective elements are analyzed; and also the most practical case – active-inductive load with various values of reactive power factors -0,1; 0,2; 0,3 and capacitive corrective element. An important feature of applying the «open triangle» scheme in the structure of a rural low-voltage distribution network with a voltage of 220 V, from the standpoint of achieving practically necessary and sufficient energy efficiency - not exceeding 10 % of the additional power losses, is the ability to compensate for reactive power and balancing the phase currents of the network line using only one corrective capacitor of relatively low power - about 50 % of the active power of one power receiver.
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Dinh, Hien Sy, Tuan Tran Anh Thi und Luong Thi Nguyen. „SIMULATING CHARACTERISTICS OF CARBON NANOTUBE FIELD- EFFECT TRANSISTOR (CNTFET)“. Science and Technology Development Journal 13, Nr. 2 (30.06.2010): 15–27. http://dx.doi.org/10.32508/stdj.v13i2.2123.
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We provide a model of coaxial CNTFET, using single wall nanotube. These devices would exhibit wrap-around gates that maximize capacitive coupling between the gate electrode and the nanotube channel. The results of simulations of I-V characteristics for CNTFETs are presented. Here we use non-equilibrium Green’s function (NEGF) to perform simulation for CNTFET. This simulator also includes a graphic user interface (GUI) of Matlab that enables parameter entry, calculation control, display of calculation results. In this work, we review the capabilities of the simulator, summarize the theoretical approach and experimental results. Current-voltage characteristics are a function of the variables such as: diameter of CNT, the length of CNT, the gate oxide thickness, gate voltage of Vg, types of materials of Source-Drain, Gate, and temperature. The obtained I-V characteristics of the CNTFET are also presented by analytical equations.
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Hussain, Ali A.-K. „Electrical, thermal and optical characteristics of plasma torch“. Iraqi Journal of Physics (IJP) 13, Nr. 27 (04.02.2019): 151–56. http://dx.doi.org/10.30723/ijp.v13i27.273.
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Non thermal argon plasma needle at atmospheric pressure was constructed. The experimental set up was based on simple and low cost electric components that generate electrical field sufficiently high at the electrodes to ionize various gases which flow at atmospheric pressure. A high AC power supply was used with 9.6kV peak to peak and 33kHz frequency. The plasma was generated using two electrodes. The voltage and current discharge waveform were measured. The temperature of Ar gas plasma jet at different gas flow rate and distances from the plasma electrode was also recorded. It was found that the temperature increased with increasing frequency to reach the maximum value at 15 kHz, and that the current leading the voltage, which demonstrates the capacitive character of the discharge. The electron temperature was measured at about 0.61 eV, and we calculated the electron number density to be 4.38×1015 cm-3.
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Murtaza, Imran, Khasan S. Karimov, Muhammad H. Sayyad und Ibrahim Qazi. „Optoelectronic Properties of Vanadyl phthalocyanine Based Organic-Inorganic Hybrid Devices“. Applied Mechanics and Materials 110-116 (Oktober 2011): 3255–60. http://dx.doi.org/10.4028/www.scientific.net/amm.110-116.3255.
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The Optoelectronic properties of organic-inorganic hybrid devices consisting of Ag/VOPc/n-Si/Ag structure have been investigated through analyzing the current-voltage characteristics. We have also studied the effect of illumination on the open circuit voltage, capacitance and reverse resistance with consideration of VOPc film thickness. The dark I-V characteristics display rectification behaviour of such hybrid structures and a very high photo-capacitive response under illumination of 200 lx is observed. Furthermore due to the generation of photo induced charges, under illumination, the decrease in reverse bias resistance to one third of its value is observed.
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Wang, Hongliang, Xiangjun Wang, Changde He und Chenyang Xue. „Reception characteristics investigation and measurement of capacitive micromachined ultrasonic transducer“. Sensor Review 40, Nr. 2 (09.09.2019): 237–46. http://dx.doi.org/10.1108/sr-06-2019-0146.
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Purpose As a new type of ultrasonic transducer with significant advantages, capacitive micromachined ultrasonic transducer (CMUT) has good application prospect. The reception characteristic of the CMUT is one of the important factors determining the application effect. This paper aims to study the reception characteristics of CMUT. Design/methodology/approach In this paper, the state equation is deduced and the analysis model is established in SIMULINK environment based on the lumped parameter system model of the CMUT cell. Based on this analysis model, the influencing factors of CMUT reception characteristics are studied and investigated, and the time-domain and frequency-domain characteristics are investigated in detail. Findings The analysis results show that parameters directly affect the reception characteristics of the CMUT, such as direct current (DC) bias voltage, input sound pressure amplitude and frequency. At the same time, the measurement system is built and the reception characteristics are verified. Originality/value This paper provides an effective method for rapid analyzing the reception characteristics of CMUT. These results provide an important theoretical basis and reference for further optimization of CMUT structure design, and lay a good foundation for the practical application measurement.
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Onufrienko, V. M. „Capacitance-voltage differintegral characteristics of fractal field-effect device“. Journal of Physics and Electronics 28, Nr. 2 (09.12.2020): 57–62. http://dx.doi.org/10.15421/332021.
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In the present paper, we use the theoretical model of fractal elements to study the charge and capacitance-voltage differintegral characteristics of a fractal field-effect device. The control of the charge channel and the capacity of a fractal nanotransistor is revealed by changing the scaling of the nanolayer, the charge density in which is determined from the sum of the charges of electrons, holes, and ionized impurities. The significant influence of fractal charge distribution carriers on the device capacitance at high frequencies is noted. This fact theoretically confirms the possibility of increasing the capacitance of metal-oxide-semiconductor structures to increase the efficiency of the field-effect-transistors. The comparison of the obtained expressions shows the strong influence of fractal medium on the electric field size and charge density in a semiconductor that is followed by the change of capacitive device parameters. The differential-integral method for modeling artificial metamaterial fractal radioelements with necessary electrical characteristics is proposed.
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Kurniawan, Sigit, D. J. Djoko Satjojo H. S. und Setyawan P Sakti. „Voltage-Current Measurement and Circuit Model Simulation to Characterize Electrical Properties of 40 kHz Capacitive Coupled Plasma (CCP) By Means of Pressure Variation“. Applied Physics Research 8, Nr. 2 (15.02.2016): 10. http://dx.doi.org/10.5539/apr.v8n2p10.
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<p class="1Body">The change of plasma conditions caused by pressure increasing can affect the change of electrical characteristic of plasma and influence in each of plasma process is done, its change can be estimated by means of voltage-current characteristics from V-I measurement and simulation of the plasma equivalent circuit model. This study is investigation of electrical characteristic of 40 kHz Capacitive Coupled Plasma (CCP) from V-I measurement were combined by simulation of the plasma circuit model, the goal study is observation of the change of electrical properties of plasma in different pressure conditions. The simulation results show that the output of circuit model in the simulation are similar with voltage-current characteristic from V-I measurement in 300 mTorr-900 mTorr pressure conditions. From the characterization, can be concluded that the electrical properties of CCP can be estimated by using the resistor and capacitor values of circuit model in the simulation to get similarity characteristic with voltage-current from V-I measurement.</p>
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Tripathi, Sudhanshu, Rekha Agarwal, Rashmi Vashisth und Devraj Singh. „Capacitive micromachined ultrasonic transducers: Transmission evaluation with different membrane materials and dimensions“. tm - Technisches Messen 88, Nr. 4 (18.03.2021): 251–59. http://dx.doi.org/10.1515/teme-2020-0073.
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Abstract Capacitive micromachined ultrasonic transducers (CMUTs) are dominant in generating and receiving acoustic signals. CMUT transmission efficiency solely depends upon the membrane material utilized. This work presents the structural examination of receiving and transmitting characteristics of CMUT with divergent membrane materials, namely Silicon (Si), Silicon Nitride ( Si 3 N 4 {\mathrm{Si}_{3}}{\text{N}_{4}} ), Indium Phosphide (InP), Zinc Oxide (ZnO), and Polysilicon (Poly-Si). The analysis includes the membrane deflection, pull-in voltage, output pressure, resonant frequency and capacitance modification with variable DC voltage. It has been found that InP gives the pull-in voltage comparable to Si in the receiving mode and have more transduction efficiency in transmitting mode. Effect of dimensions of CMUT on pull-in voltage and resonant frequency are also discussed. The major contribution lies in the analytical and estimation study of CMUT for appropriate membrane material selection meant for transmission and reception in the field of pressure sensing application.
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Ye, Xiangyang, und Mahesh Dhotre. „CFD Simulation of Transonic Flow in High-Voltage Circuit Breaker“. International Journal of Chemical Engineering 2012 (2012): 1–9. http://dx.doi.org/10.1155/2012/609486.
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A high-voltage circuit breaker is an indispensable piece of equipment in the electric transmission and distribution systems. Transonic flow typically occurs inside breaking chamber during the current interruption, which determines the insulating characteristics of gas. Therefore, accurate compressible flow simulations are required to improve the prediction of the breakdown voltages in various test duties of high-voltage circuit breakers. In this work, investigation of the impact of the solvers on the prediction capability of the breakdown voltages in capacitive switching is presented. For this purpose, a number of compressible nozzle flow validation cases have been presented. The investigation is then further extended for a real high-voltage circuit breaker geometry. The correlation between the flow prediction accuracy and the breakdown voltage prediction capability is identified.
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Shaoqing Chen, Hanyu Wang, Lin Du und Jianming Li. „Research on Characteristics of Noncontact Capacitive Voltage Divider Monitoring System Under AC and Lightning Overvoltages“. IEEE Transactions on Applied Superconductivity 24, Nr. 5 (Oktober 2014): 1–3. http://dx.doi.org/10.1109/tasc.2014.2340451.
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Liu, Xingjie, Yamin Zeng, Baoping An und Xiaolei Zhang. „Research on Characteristics of ECVT for Power Quality Detection and Optimum Design of Its Parameter“. Energies 12, Nr. 12 (24.06.2019): 2416. http://dx.doi.org/10.3390/en12122416.
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Electronic Capacitive Voltage Transformer (ECVT), connecting the transmission system and measuring device, is the key equipment of digital substation in the distribution network. Its frequency characteristics and the rapid transient response performance exert decisive effects on whether it is in keeping with the power quality requirements for wide frequency domain and high precision detection. Many detection methods that require special testing equipment have limitations of high-cost and complexity in project implementation. We establish the mathematical model of ECVT, which is utilized to study its integrative characteristics based on the definitions of frequency response and transient voltage error. Besides, the harmonic and transient disturbance detection performances are analyzed comprehensively with the model by simulation. Then, we propose a multi-objective parameter optimization design model with minimization of transient voltage decay duration, maximization of frequency bandwidth and minimization of transient impulse voltage, which is solved through the entropy weighting method and genetic algorithm. The analysis and optimization results indicate that selecting resistor divider through the proposed method can achieve data transmission results with acceptable accuracy. Further, its superior performance on transforming transient disturbances conforms to the distribution network’s electric energy quality requirements.
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Zhang, Ziwei, Dengwei Ding, Liang He, Weidong Liu, Cuifen Bai und Junjun Liu. „Transient Voltage UWB Online Monitoring System for Insulation Failure Analysis and Fault Location of GIL“. Energies 14, Nr. 16 (09.08.2021): 4863. http://dx.doi.org/10.3390/en14164863.
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Transient voltage generated in ultra-high voltage (UHV) transmission system has a severe impact on the insulation state of gas-insulated transmission lines (GIL). In order to monitor the transient voltage process occurring in UHV GIL during operation, this paper constructs a transient voltage ultra-wideband (UWB) online monitoring system based on capacitive voltage division. This system has been applied in an 1100 kilovolt (kV) GIL utility tunnel project. It can be used to analyze the characteristics of the recorded transient voltage waveforms for distinguishing different types of insulation failure. In this paper, through the case studies in time domain and time–frequency domain, the case of SF6 gap breakdown and that of post insulator flashover have differentiated characteristics in instantaneous frequency. Additionally, a case of secondary discharge is successfully estimated through the time–frequency distribution of the transient voltage. In order to find the malfunctioning chamber of GIL rapidly, a two-terminal TW-based fault location method based on this monitoring system is developed in this paper. The case study validates the locating accuracy which directly support for shortening the maintenance time of GIL.
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Han, Yanzan, und Jimeng Zhang. „Recognition Algorithm of Transient Overvoltage Characteristic Based on Symmetrical Components Estimation“. Symmetry 12, Nr. 1 (07.01.2020): 114. http://dx.doi.org/10.3390/sym12010114.
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The recognition of transient overvoltage characteristics is the premise of disturbance compensation of the transient overvoltage. Based on that, the recognition algorithm of transient overvoltage characteristics based on symmetrical components estimation was proposed. The generation mechanism of the transient overvoltage in gas insulated switchgear (GIS) was analyzed. Then, the transient overvoltage was measured via the capacitive sensor method. The three-phase voltage of ultra-high voltage grid was asymmetrical when the transient overvoltage appeared. At present, the asymmetrical three-phase voltage was decomposed into the superposition of a symmetrical positive-sequence component, a negative-sequence component, and a zero-sequence component via the symmetrical components estimation to build the superposition model. The model was decomposed via the trigonometric identity and the modified neural network of the least mean square learning rule was used to estimate the parameter vector of the characteristic quantity of the transient overvoltage in real time. The feasibility of the proposed algorithm was verified via comparing the simulation of the proposed algorithm and the algorithm based on dp transformation. The experimental results show that the proposed algorithm has the advantages of a small operand, high detection precision, and fast action.
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Sobas, Pawel A., Ola Nilsen, Helmer Fjellvåg und Bengt Gunnar Svensson. „Electrical Properties and Gas Sensing Characteristics of the Al2O3/4H SiC Interface Studied by Impedance Spectroscopy“. Materials Science Forum 645-648 (April 2010): 531–34. http://dx.doi.org/10.4028/www.scientific.net/msf.645-648.531.
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Using impedance spectroscopy (IS) for characterization of the electrical properties and gas sensing characteristics of Al2O3/4H-SiC (MOS) structures, insight on the capacitive and resistive contributions in the interfacial region of the MOS structures is obtained. Applying DC bias voltages between accumulation and depletion (corresponding to the interfacial region) allows investigation of the voltage shift of the capacitance versus voltage (CV) curve at different temperatures and atmospheres. This voltage shift forms the basis to use the MOS structure as a gas sensor. The MOS capacitance, as extracted from IS data, is different from the one obtained using CV measurements, due to the ability of distinguishing the resistive contribution (using IS). Voltage shifts between 1 and 2 V are clearly revealed during exposure to hydrogen and oxygen, and this shift exhibits a long-term stability of operation at temperatures up to 500°C. Hence, Al2O3 exhibits great promise as a gate dielectric in MOS-based gas detecting devices for use at elevated temperatures.
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Tonkoshkur, A. S., I. V. Gomilko und A. Yu Lyashkov. „Percolation effects in the capacitive properties of metal-oxide varistors in the range of high voltage“. Journal of Advanced Dielectrics 04, Nr. 02 (April 2014): 1450013. http://dx.doi.org/10.1142/s2010135x14500131.
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C–V characteristics of ZnO -based ceramic structures used in manufacturing high-voltage and low-voltage varistors of different chemical compositions and manufacturing techniques have been investigated. A correlation between the intensity of electric field corresponding to transition of the C–V characteristics to the negative capacitances and average sizes of grains of a varistor structure has been established. Obtained data have been interpreted with the use of notions of the percolation theory of electric conductivity. The Shklovskii–De Gennes model has been used. It has been shown that on the highly nonlinear segment of C–V characteristics of a varistor structure, the size of an infinite cluster are limited to several intercrystallite potential barriers. This result is observed in all kinds of investigated varistor ceramics.
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HUANG, WEI, YIMIN ZHANG, SHENXU BAO und SHAOXIAN SONG. „DESALINATION BY CAPACITIVE DEIONIZATION WITH CARBON-BASED MATERIALS AS ELECTRODE: A REVIEW“. Surface Review and Letters 20, Nr. 06 (Dezember 2013): 1330003. http://dx.doi.org/10.1142/s0218625x13300050.
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Capacitive deionization (CDI) is a recently developed electrosorption technology for deionization using porous electrodes. The electrode materials play an important role in the efficiency. This paper highlights the current research status of carbon-based materials as the electrode and the adsorption models in the CDI. It includes the types and performances of carbon-based materials and the main influencing factors of the desalination characteristics. Also, operating parameters such as charging voltage, flow rate, concentration of feed solution, treating time and temperature are summarized.
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Makasheva, Svetlana, Pavel Pinchukov, Aleksandr Mamaev und Sergey Terleckiy. „ESTIMATE OF VOLTAGE QUALITY ON TRACTION SUBSTATION BUSES OF 27.5 kV WITH LONGITUDINAL CAPACITIVE COMPENSATION DEVICE“. Bulletin of Bryansk state technical university 2020, Nr. 3 (05.03.2020): 11–20. http://dx.doi.org/10.30987/1999-8775-2020-3-11-20.
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The paper is dedicated to the investigation of electric energy quality in AC traction network. The object of investigations is voltage in the AC traction network on buses of 27.5 kV in the AC functioning substation. The probabilistic-statistical value of the voltage level and values of electric energy quality according to voltage non-sinusoidality is under fulfillment.
There are shown numerical characteristics and histograms of the distribution density of values under analysis for two operation modes of the AC traction substation – switching on and off of the longitudinal capacitive compensation device formed on the basis of natural measurements. The probabilistic-statistical processing of natural measurements results in power supply arms of the functioning traction substation located in the Far-East of the Russian Federation is carried out.
The analysis results are shown as distribution density histograms of random values according to the standard law and in a table form. The longitudinal compensation device impact upon quality values of electric power according to the voltage is under consideration.
The calculated indices of electric power quality at the traction substation are compared with the requirements of GOST 32144-2013 in force. It is mentioned that upon buses of 27.5 kV of the traction substation both in the mode of UPK switching on, and in the mode of its switching off the electric power quality by the factor of voltage harmonic components does not satisfy the requirements of GOST 32144-2013 in a number of harmonics. On the basis of the complex estimate of voltage parameters there is drawn a conclusion of the positive impact of longitudinal capacitive compensation devices upon voltage level and the absence of a distinct effect upon a harmonic structure of voltage in a traction network at longitudinal compensation switching on. The conclusion is drawn about filtration expediency of voltage highest harmonic components in power supply arms of the traction substation to bring quality indices on voltage non-sinusoidality to the requirements of the standard in force.
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Shcherba, A. A., A. D. Podoltsev und I. M. Kucheriava. „SYSTEM FOR REMOTE MONITORING OF HIGH-VOLTAGE CABLE LINE STATE“. Praci elektrodinamiki Nacionalanoi akademii nauk Ukraini Institutu 2020, Nr. 57 (02.12.2020): 10–14. http://dx.doi.org/10.15407/publishing2020.57.010.
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The article proposes a device for remote monitoring of high-voltage cable line state. The device gives a possibility to measure simultaneously several diagnostic characteristics, i.e. the temperature of cable outer sheath, electric current in cable core, capacitive current to earth and uses a specially designed internal electric power source that directly converts the energy of cable electromagnetic field into electric energy with necessary parameters. By computer simulation, the temperature field distribution in the cable cores of 330 kV cable line is determined and the quantitative relationship between the directly measured temperature on the cable outer sheath and the temperature values of the cable core and insulation, which are important diagnostic characteristics of the thermal state of power cables is revealed. References 5, figures 3.
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Ershadi, Tohid Zargar, Ehsan Salimi und Habibollah Zolfkhani. „Design and Simulation a Low Voltage Actuated RF MEMS Switch with Improve RF Characteristics“. Advanced Materials Research 403-408 (November 2011): 4199–204. http://dx.doi.org/10.4028/www.scientific.net/amr.403-408.4199.
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This paper present, the design and simulation of the Ka to v band RF-MEMS capacitive switch. The mechanic design and analysis of the RF-MEMS switches are based on both the finite element method and the full-wave electromagnetic simulation. A double-beam switch with a high impedance short transmission line is proposed to improve RF characteristics. The electronic characteristics, of the switches including insertion and return losses in up-state position, were more than -0.11 dB and less than -23 dB , respectively and isolation on down-state position was more than -30 dB on 50 GHZ frequency. In order to make lower actuated voltage, a serpentine spring folded suspension beam and low actuated area were used so that some important issues such as life and reliability of switch were considered in design.
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Soon-Gul Lee, Yunseok Hwang und Yunsung Huh. „Effects of capacitive shunt on the current-voltage characteristics of high T/sub c/ Josephson junctions“. IEEE Transactions on Appiled Superconductivity 9, Nr. 2 (Juni 1999): 3472–74. http://dx.doi.org/10.1109/77.783777.
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Wan, Lei, Canchang Liu, Weixu Kong, Yingchao Zhou und Chicheng Ma. „Nonlinear vibration control of nano-beam based on capacitive acoustic sensors“. International Journal of Applied Electromagnetics and Mechanics 64, Nr. 1-4 (10.12.2020): 421–29. http://dx.doi.org/10.3233/jae-209348.
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The nonlinear vibration control of the Euler–Bernoulli beam is studied based on capacitive micro-mechanical acoustic sensors The graphene film has the characteristics of high sensitivity and high accuracy which can be applied to sense the vibration signal. Capacitive micro-mechanical acoustic sensors can be used to detect the acoustic signal of the vibration of the nano-beam. The nonlinear vibration control equation of nano-beam can be established with the displacement and velocity voltage feedback controller based on capacitive micro-mechanical acoustic sensors. The amplitude-frequency response equation of the primary resonance of nano-beam can be gotten by using the multiple scales method. The relationship between the nonlinear vibration of nano-beam and system parameters is investigated. The influencing factors of how to weak system nonlinearity and enhance system stability are analyzed. The static bifurcation behavior of the system is discussed. The numerical results show that the nonlinearity of vibration can be reduced and the stability of the system can be improved by selecting the appropriate control gains and appropriately reducing the amplitude of DC and AC excitation voltages.
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Kovernikova, Lidiia I. „Resonance Modes at Harmonics Frequencies in Electrical Networks“. E3S Web of Conferences 209 (2020): 07006. http://dx.doi.org/10.1051/e3sconf/202020907006.
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Resonance modes at harmonic frequencies in electrical networks are a serious problem. They arise due to the availability of electrical equipment with capacitive and inductive elements. The values of the harmonics of currents and voltages increase at resonances. The voltage quality indices in resonant modes exceed the limit values. Harmonics cause energy losses in electrical equipment, reduce its service life, create economic damage. Capacitor banks are often damaged by resonances. Network nodes with resonant circuits and resonant harmonics can be determined using the frequency characteristics of the nodal reactance (susceptance). The paper presents an algorithm and HARMONICS software for the analysis and forecasting of resonance modes, the results of studies of resonance modes in the high-voltage networks of Eastern Siberia.
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Ahn, Bong Young, Ki Bok Kim, Hae Won Park, Young Joo Kim und Yong Seok Kwak. „Design and Characterization of Capacitive Micromachined Ultrasonic Transducer“. Key Engineering Materials 321-323 (Oktober 2006): 132–35. http://dx.doi.org/10.4028/www.scientific.net/kem.321-323.132.
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As cMUTs (capacitive Micromachined Ultrasonic Transducer) offer numerous advantages over traditional transducers in terms of efficiency, bandwidth, and cost, they are expected to replace piezoelectric transducers in many applications. In particular, 2D-array cMUTs have aroused great interest in the medical engineering society because of their ability to materialize a true volumetric ultrasonic image. In this study, single element cMUTs with 32 x 32 and 64 x 64 cells were successfully fabricated. The diameter and thickness of the membrane are 35 and 1000 nm, respectively, with a sacrificial layer thickness of 600 nm. The electric characteristics of the fabricated cMUT were measured. Tests on the efficiencies of the cMUT in terms of wave generation and in terms of detection according to the bias and pulse voltage were performed in an air atmosphere.
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KHAN, MOHAMMED ZAID, SURENDER SINGH TANWAR, RAVINDRA DAYAMA, RAHUL RAJ CHOUDHARY und RAVINDRA MANGAL. „CONVERSION OF IMPULSE VOLTAGE GENERATOR INTO STEEP WAVE IMPULSE TEST-EQUIPMENT“. International Journal of Modern Physics: Conference Series 22 (Januar 2013): 637–44. http://dx.doi.org/10.1142/s2010194513010787.
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This paper demonstrates the alternative measures to generate the Steep wave impulse by using Impulse Voltage Generator (IVG) for high voltage testing of porcelain insulators. The modification of IVG by incorporating compensation of resistor, inductor, and capacitor has been achieved and further performance of the modified system has been analyzed by applying the generated lightning impulse and analyzing the electrical characteristics of impulse waves under standard lightning and fast rise multiple lightning waveform to determine the effect to improve rise time. The advantageous results have been received and being reported such as increase in overshoot compensation, increase in capacitive and inductive load ranges. Such further reduces the duration of oscillations of standard impulse voltages. The reduction in oscillation duration of steep front impulse voltages may be utilized in up gradation of Impulse Voltage Generator System. Stray capacitance could further be added in order to get the minimized difference of measurement between simulation and the field establishment.
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Barakou, Steennis und Wouters. „Accuracy and Reliability of Switching Transients Measurement with Open-Air Capacitive Sensors“. Energies 12, Nr. 7 (11.04.2019): 1405. http://dx.doi.org/10.3390/en12071405.
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Contactless capacitive (open-air) sensors are applied to monitor overvoltages near overhead line terminations at a substation or at the transition from underground cables to overhead lines. It is shown that these sensors, applied in a differentiating/integrating measuring concept, can result in excellent characteristics in terms of electromagnetic compatibility. The inherent cross-coupling from open-air sensors to other phases is dealt with. The paper describes a method to calibrate the sensor to line coupling matrix based on assumed 50 Hz symmetric phase voltages and in particular focuses on uncertainty analysis of assumptions made. Network simulation shows that predicted maximum overvoltages agree within typically 7% compared to reconstructed values from measurement, also with significant cross-coupling. Transient voltages from energization of an (extra-)high voltage connection can cause large and steep rising ground currents near the line terminations. Comparison with results obtained by a capacitive divider confirms the intrinsic capability in interference rejection by the differentiating/integrating measurement methodology.
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Yan, Bin, Wei Zheng Yuan, Yi Ting Yu, Lan Lan Wang, Da Yong Qiao und Tai Ping Li. „Study of Control System for a Micro Programmable Blazed Grating“. Advanced Materials Research 60-61 (Januar 2009): 180–84. http://dx.doi.org/10.4028/www.scientific.net/amr.60-61.180.
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Based on a new micro programmable grating with changeable blazed angle, the control system was recently designed and developed, enabling the normal operation for the fabricated grating. The basic requirements for the control system are high reliability, efficiency and miniaturization. This paper presents the specific design objectives for the control system according to the grating’s operation characteristics. The whole control system contains three key modules—generator & communication module, high-voltage amplifier module and computer software module. Generator & communication module includes a high-performance microcontroller (C8051F020), a D/a converter (AD7305) and universal serial bus (USB) interface. As for the considered performances, PA69 is complete capable of magnifying the driving voltage signals to drive the grating in high-voltage amplifier module. After the development of the control system, an experiment was performed for investigating the dynamic frequency response of the grating. In conclusion, it has the advantages of wide output of voltage, high frequency response, driving ability in wide capacitive load range and real-time control properties. Hence, it is appropriate for controlling MEMS programmable grating in complicated and dynamic conditions.
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Naito, Yasuyuki, Kunihiko Nakamura und Keisuke Uenishi. „Laterally Movable Triple Electrodes Actuator toward Low Voltage and Fast Response RF-MEMS Switches“. Sensors 19, Nr. 4 (19.02.2019): 864. http://dx.doi.org/10.3390/s19040864.
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A novel actuator toward a low voltage actuation and fast response in RF-MEMS (radio frequency micro-electro-mechanical systems) switches is reported in this paper. The switch is comprised of laterally movable triple electrodes, which are bistable by electrostatic forces applied for not only the on-state, but also the off-state. The bistable triple electrodes enable the implementation of capacitive series and shunt type switches on a single switch, which leads to high isolation in spite of the small gap between the electrodes on the series switch. These features of the actuator are effective for a low voltage and fast response actuation in both the on- and off-state. The structure was designed in RF from a mechanical point of view. The laterally movable electrodes were achieved using a simple, low-cost two-mask process with 2.0 µm thick sputtered aluminum. The characteristics of switching response time and actuation voltage were 5.0 µs and 9.0 V, respectively.
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Cuzminschi, Marina, und Alexei Zubarev. „Charging of Superconducting Layers in Arrays of Coupled Josephson Junctions for Overcritical Currents“. Crystals 9, Nr. 7 (27.06.2019): 327. http://dx.doi.org/10.3390/cryst9070327.
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In this work, we effectuated the numerical simulations of the phase dynamics of an array of Josephson junctions taking into account the capacitive coupling between the neighboring junctions and the diffusion current in the stack. We observed that, if we increase the coupling and the dissipation parameters, the IV characteristic changes qualitatively from the IV characteristics studied before. For currents greater than the critical one, we obtained an additional branch in the IV characteristics. This branch is characterized by a lower voltage than the outermost one. Moreover, we obtained an additional charging of the superconducting layers in the IV region for currents greater than the critical one. We studied the time evolution of this charging by the means of Fast Fourier Transform. We proved that the charge density wave associated with this charging has a complex spectral structure. In addition, we analyzed the behavior of the system for different boundary conditions, appropriate to different experimental setups.
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Kim, Kwonse, Jaeyoung Han und Seokyeon Im. „Evaluation of the Ignition Effect in Constant Volume Combustion Chamber Based on Matching Effect of High Voltage (MEHV) Method“. Energies 13, Nr. 19 (29.09.2020): 5084. http://dx.doi.org/10.3390/en13195084.
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The characteristics of spark ignition with a constant volume combustion chamber (CVCC) is evaluated for the efficiency of capacitive-assisted ignition (CAI), such as spark kernel and flame growth. The conventional spark method and matching effect of high voltage (MEHV) method are evaluated to compare the spark growth distribution characteristics. To do this study, a plasma system is used and is consisted of input power, three capacitors, a transformer, high voltage cable, J-type of a spark plug, diode, and CVCC. The experiment is conducted under various operating conditions, such as 1 bar, 295 K of initial temperature, 50, 100, 150 V of ignition box, 400 V of MEHV, 0.7 ms of spark duration, and 0 kΩ of plug resistor. The results show that the spark growth at the initial voltages of 100 V and 150 V has the same characteristic, and the surface area is increased by 13 mm2 at 150 V compared to 100 V because capacitance energy stored in three capacitors is efficiently induced by the effect of dielectric breakdown and electron collision. Consequently, the spark growth of MEVH is widely distributed atmospheric more than the conventional spark, and the internal temperature of the spark kernel could be presumed to change the non-thermal plasma to thermal plasma by MEHV.
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Yu, Pei Jun. „Study on Artificial Polycrystalline Piezoelectric Material with the Calibration Mechanism of the Micro-Displacement Sensor Based on Piezoelectric Ceramic“. Advanced Materials Research 703 (Juni 2013): 312–15. http://dx.doi.org/10.4028/www.scientific.net/amr.703.312.
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In this paper, a calibration mechanism of sensor based on artificial polycrystalline piezoelectric material and a kind of micro-voltage output system have been designed through understanding the characteristics and the parameters of the capacitive displacement sensor, so as to achieve the sensor calibration interval reaches the piezoelectric ceramic resolution of 5 nm. Through the measured values in the condition that 10mV/100mV is input to piezoelectric ceramic, it can be seen that the design meets the initial requirements. Such mechanism can be used for the calibration of a variety of high-precision sensors; however, it must be used in a stable environment.
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Tong, Tao, Xinyan Zhan, Liang Gao und Jiajun Zhang. „Harmonic Coupling Analysis and Suppression Strategy of Grid-connected Photovoltaic Inverter“. MATEC Web of Conferences 173 (2018): 03077. http://dx.doi.org/10.1051/matecconf/201817303077.
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For the complex harmonic coupling problem caused by the parallel connection of grid-connected photovoltaic inverters to the grid, the mathematical models of a single three-phase inverter and two three-phase inverters connected in parallel are established in this paper. The transfer function is derived and the resonant characteristics of grid-connected single inverter and parallel grid-connected multi-inverters are analyzed by using Bode diagram. On the basis of the maximum power tracking link, This paper proposes a control strategy which combines the double closed-loop of current by using grid-connected voltage and capacitive current with the proportional feedforward compensation of grid voltage, which maximizes the use of solar energy and has a better harmonic resonance suppression capability at the same time. The effectiveness and correctness of the proposed control strategy are verified by Matlab/Simulink system simulation.
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Morales-Aragonés, José Ignacio, Miguel Dávila-Sacoto, Luis G. González, Víctor Alonso-Gómez, Sara Gallardo-Saavedra und Luis Hernández-Callejo. „A Review of I–V Tracers for Photovoltaic Modules: Topologies and Challenges“. Electronics 10, Nr. 11 (27.05.2021): 1283. http://dx.doi.org/10.3390/electronics10111283.
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Current–voltage (I–V) curve tracers are used for measuring voltage and current in photovoltaic (PV) modules. I–V curves allow identifying certain faults in the photovoltaic module, as well as quantifying the power performance of the device. I–V curve tracers are present in different topologies and configurations, by means of rheostats, capacitive loads, electronic loads, transistors, or by means of DC–DC converters. This article focuses on presenting all these configurations. The paper shows the electrical parameters to which the electronic elements of the equipment are exposed using LTSpice, facilitating the appropriate topology selection. Additionally, a comparison has been included between the different I–V tracers’ topologies, analyzing their advantages and disadvantages, considering different factors such as their flexibility, modularity, cost, precision, speed or rating, as well as the characteristics of the different DC–DC converters.
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Ashmarin, Vasiliy V., Denis G. Osipov und Igor V. Rezyukov. „DESIGN FEATURES AND THE TIME CHARACTERISTICS OF THE RAIL FOUR-CHANNEL SPARK GAP WITH FIELD DISTORTION“. Vestnik Chuvashskogo universiteta, Nr. 1 (25.03.2021): 27–35. http://dx.doi.org/10.47026/1810-1909-2021-1-27-35.
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The article discusses the design features of a four-channel rail arrester with field distortion and the results of the study of its time characteristics. The need for this work related to the development of such dischargers due to the lack of their analogues is due to the widespread use of capacitive energy storage devices as power sources for electrodynamics mass accelerators. At the present stage of development of science and technology, the use of such accelerators is the most promising for creating experimental stands for modeling in laboratory conditions the processes of high-speed interaction of aircraft structural elements with particles of different masses and different origins. According to the operating conditions of the experimental stands and a wide range of changes in both particle masses and interaction velocities, the amplitude values of currents through the low-inductive load of the mass accelerator vary from hundreds of kilo amperes to several million amperes at acceleration times from units to hundreds of microseconds. With this in mind, capacitive energy storage devices are made in a multi-module design. Each module is switched to the load by its own switch. To extend the range of operation of the drive, provide the required erosion resistance of the electrodes of the switch, the stability of the discharge formation at parallel operation of switches developed construction of a rail four-channel spark gap with the distortion field, experimental and theoretical study of the effect of the ratio of the geometric dimensions of the inter electrode gap for obtaining small values for the delay time of the discharge.
As a result of the research, it is shown that the value of the delay time tzap depends on the shape and diameter of the main electrodes, the material of the electrodes, the distance between the main and the control electrode, the threshold voltage, as well as the degree of inhomogeneity of the field in the inter electrode gap.
The obtained analytical expressions allow us to determine the values of threshold stresses and delay times, taking into account the statistical delay time and the time of discharge formation.
It is established that the value of the delay time is significantly affected by the field inhomogeneity coefficient and the configuration of the control electrode.
It is noted that when the operating voltage on the arrester exceeds the threshold voltage, the delay time of the switch lies in the nanosecond region.
The value of the threshold voltage Upor, at which the process of direct transformation of the streamer into a spark discharge with high conductivity, followed by a breakdown of the inter electrode gap, is determined.
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Bezawada, Yashwanth, und Yucheng Zhang. „A Case Study: Influence of Circuit Impedance on the Performance of Class-E2 Resonant Power Converter for Capacitive Wireless Power Transfer“. Electronics 10, Nr. 12 (18.06.2021): 1461. http://dx.doi.org/10.3390/electronics10121461.
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The evolution of power electronics led to rapid development in wireless charging technology; as a result, a single active switch topology was introduced. The present market utilizes inductive wireless power transfer (IPT); because of the disadvantages of cost, size, and safety concerns, research on wireless power transfer was diverted towards capacitive wireless power transfer (CPT). This paper studies the optimal impedance tracking of the capacitive wireless power transfer system for maximum power transfer. Compared to prior methods developed for maximum power point tracking in power control, this paper proposes a new approach by means of finding impedance characteristics of the CPT system for a certain range of frequencies. Considering the drone battery as an application, a single active switch Class-E2 resonant converter with circular coupling plates is utilized. Impedance characteristics are identified with the help of equations related to the input and resonant impedance. The impedance tracking is laid out for various resonant inductors, and the difference in current peak is observed for each case. Simulations verify and provide additional information on the reactive type. Additionally, hardware tests provide the variation of input current and output voltage for a range of frequencies from 70 kHz to 300 kHz. Efficiency at the optimal impedance points for a resonant inductor with 50 μH and 100 μH are tested and analyzed. It is noted that the efficiency for a resonant inductor with 50 μH is 8% higher compared to the CPT with a 100 μH resonant inductor. Further hardware tests were performed to investigate the impact of frequency and duty cycle variation. Zero-voltage-switching (ZVS) limits have been discussed with respect to both frequency and duty cycle.
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MohdIsa, WanHasbullah, Andres Hunt und S. Hassan HosseinNia. „Sensing and Self-Sensing Actuation Methods for Ionic Polymer–Metal Composite (IPMC): A Review“. Sensors 19, Nr. 18 (14.09.2019): 3967. http://dx.doi.org/10.3390/s19183967.
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Ionic polymer–metal composites (IPMC) are smart material transducers that bend in response to low-voltage stimuli and generate voltage in response to bending. IPMCs are mechanically compliant, simple in construction, and easy to cut into desired shape. This allows the designing of novel sensing and actuation systems, e.g., for soft and bio-inspired robotics. IPMC sensing can be implemented in multiple ways, resulting in significantly different sensing characteristics. This paper will review the methods and research efforts to use IPMCs as deformation sensors. We will address efforts to model the IPMC sensing phenomenon, and implementation and characteristics of different IPMC sensing methods. Proposed sensing methods are divided into active sensing, passive sensing, and self-sensing actuation (SSA), whereas the active sensing methods measure one of IPMC-generated voltage, charge, or current; passive methods measure variations in IPMC impedances, or use it in capacitive sensor element circuit, and SSA methods implement simultaneous sensing and actuation on the same IPMC sample. Frequency ranges for reliable sensing vary among the methods, and no single method has been demonstrated to be effective for sensing in the full spectrum of IPMC actuation capabilities, i.e., from DC to ∼100 Hz. However, this limitation can be overcome by combining several sensing methods.
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Sharma, Rashmi, Rekha Agarwal, Ashwani Kumar Dubey und Anil Arora. „Design and Analysis of Capacitive Micromachined Ultrasonic Transducer“. Recent Patents on Engineering 13, Nr. 2 (27.05.2019): 108–16. http://dx.doi.org/10.2174/1872212112666180214141506.
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Background:Objective:To simulate a Micromechanical systems (MEMS) based CMUT working as a transmitter with the existing design and provide comparison within the possible architectural geometries.Methods:FEM simulation software COMSOL is used to simulate the 3D model of the transducer radiating in the air. The classical thin-plate theory is employed to solve for CMUT with a circular shape which is sufficient when the ratio of the diameter to thickness of the plate is very large, an aspect common in CMUTs. The Galerkin-weighted residual technique is used to get a solution for thin plate equation with the presumption that the deflections are small in comparison to the thickness of the plate.Results:The resonant frequency of CMUT with different geometries have been calculated. The deflection of membrane with applied DC bias is shown along with collapse voltage calculation. The generated ultrasound is shown with the AC bias superimposed on the DC bias. The capacitance change with the increasing DC voltage is discussed. The deflection of membrane is maximum as the resonance frequency is proved.Conclusion:The review of Capacitive Micromachined Ultrasonic Transducer architectures with different shapes is highlighted. The working behavior of CMUT with suitable dimension is simulated in 3D providing researcher data to wisely choose the CMUT prior to the fabrication. The CMUT is prioritized on various characteristics like wafer area utilization, deflection percentage within the cavity and durability of the transducer.
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Radulescu, Victorita. „Research and Solutions to Minimize Frontal Area Overheating of Hydro Generator Stator with Vertical Axis“. Energies 14, Nr. 5 (24.02.2021): 1243. http://dx.doi.org/10.3390/en14051243.
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About ten hydroelectric power plants realized from 1970 to 1990 in Romania are confronted with stator overheating. The developed mathematical model analyzes the voltage stability based on modal analysis of the Jacobian matrix, identifying the hazardous modes of variation between voltage and flow rate, correlated with the characteristics of the analyzed generators and their response to these variations. Vulnerable elements in the system for inductive and capacitive modes of operation are identified. In these conditions, hydro generators cannot attend the secondary voltage control, not even for a frequency power dependency control. The elaborated mathematical model was tested at the hydroelectric power plants Gilceag, Mariselu, and Susag with similar functioning conditions. The necessary conditions for stator ventilation and variation of flow hydrodynamic parameters during the operation were established. The theoretical model was tested with an experimental method applied separately for the thermal and ventilation conditions. Some results obtained during the measurements are illustrated and correlated with the theoretical results. The model was tested to prevent the onset instability of voltage drops and accelerated overheating. Finally, some solutions to minimize the stators overheating based on local conditions are recommended.
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Jung, Jae Kap, Eddy So, Sang Hwa Lee und David Bennett. „Comparison of Systems Between KRISS and NRC to Evaluate the Performance Characteristics of A 400-kV Capacitive Voltage Divider“. IEEE Transactions on Instrumentation and Measurement 60, Nr. 7 (Juli 2011): 2634–41. http://dx.doi.org/10.1109/tim.2011.2126190.
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Li, Zhenxiao, Shuangpeng Hao, Fuqiang Ma und Baoming Li. „Analysis on the Influence of Breech Voltage on the Pulsed Discharge Characteristics of Capacitive Pulsed Power Supply in EML“. Journal of Physics: Conference Series 1507 (April 2020): 072006. http://dx.doi.org/10.1088/1742-6596/1507/7/072006.
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S., SKRYPNYK. „Substantiation of the choice of the replacement scheme of line for mathematical modeling of 20 kV power supplies.“ Journal of Electrical and power engineering 24, Nr. 1 (21.05.2021): 69–72. http://dx.doi.org/10.31474/2074-2630-2021-1-69-72.
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In the current global economic crisis and acute shortage of energy resources, increasing importance is attached to energy saving measures, economical and careful consumption of raw materials, materials, electricity and heat, environmental safety of industrial production. During the reconstruction of existing power supply systems of industrial enterprises, modern progressive solutions should be considered and implemented, morally and physically obsolete electrical equipment should be replaced, namely the introduction of new electrical equipment for transition from 6/10 kV to 20 kV in Ukrainian power systems. It is also necessary to pay attention to the improvement of power supply circuits and distribution networks, the implementation of complex automation of complex technological processes, rational compensation of reactive power at all levels of power supply systems. In the power system, the main transport link is the power line. Power lines (transmission lines) are long conductors suspended at a safe distance from the ground overhead lines (overhead lines) or cable lines (overhead lines) in which conductors are insulated from each other and from the environment and protected by insulation and armor electricity. Power lines are the most massive elements of the power supply system, they connect the individual nodes of its circuit. Longitudinal and transverse parameters are distinguished in alternative schemes. The load current flows through the longitudinal parameters, voltage is applied to the transverse ones. The replacement circuit of the electrical network consists of replacement circuits of the following elements: power lines, transformers, reactors, capacitors, loads, power sources. Calculating the steady-state modes of power systems, the substitution schemes of the elements are given in a single-line design, because the parameters of all phases are symmetrical. In local and local electrical networks with a relatively short length and low rated voltage, the conduction currents are small compared to load currents. Therefore, in typical electrical calculations of these networks, the capacitive conductivity of the lines is not taken into account. However, for these networks, the accounting of capacitive conductivities is necessary when considering some modes, the existence of which in itself is due only to the presence of capacitive conductivities. For example, the mode of single-phase ground fault in a network with isolated or compensated neutral or analysis of the modes of operation of neutrals of electrical networks of different voltage classes cannot be performed without taking into account the capacitive conductivity of these networks. When switching the power system of Ukraine to the nominal voltage of 20 kV, it should be taken into account that the transmission line will be replaced in the sections of both the overhead power line and cable power line, namely 35, 10, 6 kV. The replacement scheme must describe all the characteristics and properties of the elements of cable and overhead lines in accordance with real conditions. Thus, it is not expedient to use simplified substitution circuits that neglect energy parameters and properties of conductors to study the parameters of transmission lines. The use of a complete "P" -shaped scheme for the analysis of the parameters of transmission lines and transmission lines for a voltage of 20 kV is the basis of mathematical modeling of the transmission system in the distribution networks of our country.
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Masood, Bilal, M. Arif Khan, Sobia Baig, Guobing Song, Ateeq Ur Rehman, Saif Ur Rehman, Rao M. Asif und Muhammad Babar Rasheed. „Investigation of Deterministic, Statistical and Parametric NB-PLC Channel Modeling Techniques for Advanced Metering Infrastructure“. Energies 13, Nr. 12 (15.06.2020): 3098. http://dx.doi.org/10.3390/en13123098.
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This paper is focused on the channel modeling techniques for implementation of narrowband power line communication (NB-PLC) over medium voltage (MV) network for the purpose of advanced metering infrastructure (AMI). Three different types of models, based on deterministic method, statistical method, and network parameters based method are investigated in detail. Transmission line (TL) theory model is used to express the MV network as a two-port network to examine characteristics of sending and receiving NB-PLC signals. Multipath signal propagation model is used to incorporate the effect of multipath signals to determine the NB-PLC transfer function. A Simulink model is proposed which considers the values of MV network to examine the characteristics of NB-PLC signals. Frequency selectivity is also introduced in the impedances to compare variations and characteristics with constant impedances based MV network. A state-of-the-art mechanism for the modeling of capacitive coupling device, and impedances of low voltage (LV) and MV networks is developed. Moreover, a comparative analysis of TL theory and multipath signal propagation models with the proposed Simulink model is presented to validate the performance and accuracy of proposed model. This research work will pave the way to improve the efficiency of next-generation NB-PLC technologies.
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Shu, Hongchun, Na An, Bo Yang, Yue Dai und Yu Guo. „Single Pole-to-Ground Fault Analysis of MMC-HVDC Transmission Lines Based on Capacitive Fuzzy Identification Algorithm“. Energies 13, Nr. 2 (09.01.2020): 319. http://dx.doi.org/10.3390/en13020319.
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The probability of a single pole-to-ground fault in high voltage direct current (HVDC) transmission lines is relatively high. For the modular multilevel converter HVDC (MMC-HVDC) systems, when a single pole-to-ground fault occurs, the fault current is small, and it is difficult to identify the fault quickly. Through a detailed analysis of the characteristics of the single pole-to-ground fault of the MMC-HVDC transmission line, it is found that the single pole-to-ground fault has obvious capacitance-related characteristics, and the transient process after the single pole-to-ground fault is the discharge process of the distributed capacitance of the line. However, other faults do not have such obvious capacitance-related characteristics. Based on such feature, this paper proposes a novel capacitive fuzzy identification method to identify the single pole-to-ground fault. This algorithm can effectively identify both the fault of single pole-to-ground and the fault pole, which can contribute to the large database of the future smart grid.