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Journal articles on the topic 'Metal oxide varistor'

Author: Grafiati

Published: 4 June 2021

Last updated: 12 February 2022

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1

Mielcarek, Witold, Slavko Bernik, and Krystyna Prociów. "Relations between the Morphology of ZnO Powders and the Electrical Performance of ZnO Varistors." Key Engineering Materials 336-338 (April 2007): 672–75. http://dx.doi.org/10.4028/www.scientific.net/kem.336-338.672.

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Because of their unusual properties – non-ohmic behavior and the ability to absorb a lot of energy – metal-oxide varistors are widely used for the protection of electrical and electronic devices against over-voltages. ZnO ceramics have varistor properties because of their metal-oxide additives and the microstructures developed during sintering. The value of the varistor voltage depends largely on the number of conducting ZnO grains between the electrodes; this can be set by controlling the thickness of the device or the size of the grains. The desired grain size can be achieved by altering the composition of the metal-oxide additives and the sintering conditions. In this work the grain growth was controlled by combining two ZnO powders of differing sinterability in the starting material. Also, the use of BaBiO2.77 as a precursor for Bi2O3 is an innovation in varistor technology that makes it possible to reduce the amount of added metal oxides. As a result, a variety of varistors with good varistor properties and a wide range of working parameters were produced.

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2

Frigura-Iliasa, Flaviu Mihai, Sorin Musuroi, Ciprian Sorandaru, and Doru Vatau. "New Technical Parameters and Operational Improvements of the Metal Oxide Varistors Manufacturing Process." Processes 7, no. 1 (January 2, 2019): 18. http://dx.doi.org/10.3390/pr7010018.

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At the beginning, this article details the manufacturing procedures for varistor materials. Starting from the initial composition of two large series of varistors (those with two additive oxides and those with five additive oxides), there is a major overview of the main stages of the technological process and the equipment used for the production, emphasizing the technological changes that were made. The article continues with the study of the influence of the sintering pressure and the sintering temperature on the electrical properties of the varistor materials made before. There were two experimental series of 7 varistors, one series based on 2 additive oxides and one based on 5 additive oxides. Each varistor of these series was sintered at another temperature, the fundamental purpose being to determine an optimal sintering temperature for each chemical composition. A second activity consisted of manufacturing two more series of varistors with the same chemical composition (2 oxides and 5 additive oxides), which were sintered at two different pressures, for having a set of conclusions on the influence of sintering pressure on the electric performances. All conclusions are underlying a new process for manufacturing metal oxide based varistors.

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3

Tonkoshkur, A. S., I. V. Gomilko, and A. Yu Lyashkov. "Percolation effects in the capacitive properties of metal-oxide varistors in the range of high voltage." Journal of Advanced Dielectrics 04, no. 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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4

Sung, Gun Yong, Stuart McKernan, and C. Barry Carter. "Grain boundaries in zinc oxide-based varistor ceramics." Proceedings, annual meeting, Electron Microscopy Society of America 47 (August 6, 1989): 598–99. http://dx.doi.org/10.1017/s0424820100154962.

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Since the development of the zinc oxide-based varistor with highly nonlinear current-voltage characteristics and high energy absorption capabilities [1], the electro-physical behavior of non-ohmic ZnO varistors has been studied and related to the microstructure of the material, the conduction and degradation mechanisms, the dielectric properties, and the high pressure memory. An extensive research effort has been aimed at characterizing ZnO/ZnO grain boundary regions in order to explain the origin of the nonlinear current/voltage characteristics of these materials [2-4]. A typical ZnO-varistor material contains small concentrations of several metal oxides (e.g., Bi2O3, CoO, MnO, Sb2O3, and Cr2O3). Co and Mn are contained within the ZnO grains, while the other “impurities are present as several polymorphic forms of Bi2O3, the spinel, Zn7Sb2O12, and the pyrochlore Zn2Bi3Sb3O14, are present as intergranular phases [1,5-7]. The breakdown voltage depends on the number of grain boundaries between the electrodes of the ZnO varistor device [8]. Therefore, the breakdown voltage is influenced by the presence and form of these intergranular phases, and the size, shape and distribution of the ZnO grains. In ZnO-Bi2O3-MnO-TiO2-based varistor materials, the morphology of the ZnO grains is strongly influenced by their tendency to grow preferentially along the directions perpendicular to the prism planes [9] (i.e., the basal plane becomes a common grain boundary facet plane). The aim of the present study is to advance the understanding of the role of the special grain boundaries which are found in air-quenched Zn0-Bi2O3-MnO-TiO2-based varistor materials.

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5

Frigura-Iliasa, Flaviu, Sorin Musuroi, Ciprian Sorandaru, and Doru Vatau. "Case Study about the Energy Absorption Capacity of Metal Oxide Varistors with Thermal Coupling." Energies 12, no. 3 (February 8, 2019): 536. http://dx.doi.org/10.3390/en12030536.

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Metal oxide varistors are applied today inside modern surge arresters for overvoltage protection for all voltage levels. Their main issue is the thermal activation of their crossing current, which could lead to complete destruction by thermal runaway. This article presents a new technological solution developed in order to increase the thermal stability of metal oxide varistors. It consists in connecting in parallel two or more similar varistors (for dividing their current), having a thermal coupling between them (for equalizing their temperatures and forcing them to act together and simultaneously as much as possible). Starting from a finite element computer model performed for each situation (varistor standalone or parallel), up to real measurements, the thermal stability of the equipment was analyzed in permanent and impulse regime. Experiments were carried out in the same conditions. Experimental data obtain from two disk varistors corresponds very well to simulations, proving that parallel connection of varistors, combined with a thermal exchange between them is an efficient technical solution for thermal stability improvement, even if not apparently economically justified.

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6

Tsukamoto, Naoyuki, and Masaru Ishii. "Change of Varistor Voltage of Metal-oxide Varistor Influenced by Impulse Currents." IEEJ Transactions on Power and Energy 135, no. 6 (2015): 400–407. http://dx.doi.org/10.1541/ieejpes.135.400.

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7

Tonkoshkur, Alexander Sergeevich, and Alexander Vladimirovich Ivanchenko. "The effect of negative capacitance in varistor structure on the basis of its models with voltage drop on the intergranular interlayer." Multidiscipline Modeling in Materials and Structures 11, no. 4 (November 9, 2015): 598–615. http://dx.doi.org/10.1108/mmms-04-2015-0021.

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Purpose – The purpose of this paper is modeling the effect of negative capacitance in the capacitance-voltage characteristic of the intergranular potential barrier of varistor structure. Design/methodology/approach – The modeling of the capacitance-voltage characteristic of the intergranular barrier in metal oxide varistor ceramics is based on the development of the algorithm. It includes all the known mechanisms of electrotransfer in a wide range of voltages and currents, and also takes into account the voltage drop on the intergranular interlayer of intergranular potential barrier. Findings – The models and algorithms for calculating the capacitance-voltage characteristics of a single intergranular potential barrier with the use of the most established understanding used at the interpretation of the nonlinear conductivity intergranular barrier are developed. The results of the capacitance-voltage characteristics modeling correspond to the existing understanding of the electrical properties on the ac current varistor ceramics are based on zinc oxide. The model allows to predict the behavior of varistors on the alternating current (voltage). Originality/value – It is established that the recharge of the surface localized states occurs when a voltage is applied to the varistor structure, it can lead to a relaxation decrease in the width of the potential barrier overcome by tunneling electrons in the field emission from the conduction band of the one crystallite in the conduction band of the other crystallite and thus to the current backlog of applied voltage on the phase (i.e. the expression of the negative capacitance effect).

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8

Chiou, Bi-Shiou, Tzuu-Chian Chen, and Jenq-Gong Duh. "A ZnO varistor derived from metal oxide diffusion." Journal of Physics D: Applied Physics 22, no. 6 (June 14, 1989): 844–47. http://dx.doi.org/10.1088/0022-3727/22/6/023.

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9

Gutknecht, Toni, Anna Gustafsson, Christer Forsgren, Christian Ekberg, and Britt-Marie Steenari. "Investigations into Recycling Zinc from Used Metal Oxide Varistors via pH Selective Leaching: Characterization, Leaching, and Residue Analysis." Scientific World Journal 2015 (2015): 1–11. http://dx.doi.org/10.1155/2015/653219.

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Metal oxide varistors (MOVs) are a type of resistor with significantly nonlinear current-voltage characteristics commonly used in power lines to protect against overvoltages. If a proper recycling plan is developed MOVs can be an excellent source of secondary zinc because they contain over 90 weight percent zinc oxide. The oxides of antimony, bismuth, and to a lesser degree cobalt, manganese, and nickel are also present in varistors. Characterization of the MOV showed that cobalt, nickel, and manganese were not present in the varistor material at concentrations greater than one weight percent. This investigation determined whether a pH selective dissolution (leaching) process can be utilized as a starting point for hydrometallurgical recycling of the zinc in MOVs. This investigation showed it was possible to selectively leach zinc from the MOV without coleaching of bismuth and antimony by selecting a suitable pH, mainly higher than 3 for acids investigated. It was not possible to leach zinc without coleaching of manganese, cobalt, and nickel. It can be concluded from results obtained with the acids used, acetic, hydrochloric, nitric, and sulfuric, that sulfate leaching produced the most desirable results with respect to zinc leaching and it is also used extensively in industrial zinc production.

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10

Wang, Guoming, Woo-Hyun Kim, Jong-Hyuk Lee, and Gyung-Suk Kil. "Condition monitoring and deterioration analysis of metal oxide varistor." Journal of Electrical Engineering 69, no. 5 (September 1, 2018): 352–58. http://dx.doi.org/10.2478/jee-2018-0051.

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Abstract With the growing demand for application of metal-oxide varistor (MOV) in low-voltage electronic circuits for overvoltage protection, it is necessary to ensure its performance to avoid the short-circuit and the line-to-ground fault during operation. In this paper, a precise leakage current analyzer was developed to detect the total leakage current and third harmonic component of MOV for its condition monitoring. The voltage- and temperature-dependent measuring uncertainties were compensated using the multipliers. In addition, the deterioration characteristics of the MOV and the newly developed thermally protected metal-oxide varistor (TMOV) were investigated in the accelerated aging test. From the experimental results, the MOV deteriorated much faster under the lightning current impulse synchronized with power-frequency voltage. The thermally activated fuse of TMOV exploded under two types of impulses, which indicated that the TMOV is much more vulnerable and that it is difficult to diagnose the condition of energized TMOV in advance.

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11

S. Tonkoshkur, Alexander, and Alexander V. Ivanchenko. "Modeling of current-voltage characteristic of the intergranular barrier in metal oxide varistor ceramics." Multidiscipline Modeling in Materials and Structures 10, no. 3 (October 7, 2014): 362–78. http://dx.doi.org/10.1108/mmms-11-2013-0066.

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Purpose – The purpose of this paper is to develop a generalized model of the nonlinear conductivity of varistor ceramic suitable for solving problems of prediction and control of ceramic nonlinearity, stability of varistor properties. Design/methodology/approach – The modeling of current-voltage characteristic of the intergranular barrier in metal oxide varistor ceramics is based on the development of the algorithm. It includes all the known mechanisms of electrotransfer in a wide range of voltages and currents of the current-voltage characteristics, and also takes into account the deviation of the barrier form the Schottky barrier. Findings – The models of double Schottky barrier and double barrier of arbitrary form, as well as the algorithms for calculating the current-voltage characteristics of a single intergranular potential barrier and a separate “microvaristor” with the use of the most well-established understanding of the main mechanisms of electrical are developed. The results of current-voltage characteristics modeling correspond to the existing understanding of the nonlinear electrical conductivity varistor ceramics are based on zinc oxide. The model of double barrier of arbitrary form takes into account the deviation of the barrier form the Schottky barrier which is important in predicting the deformation of the current-voltage characteristics of the varistor products in the process of degradation. Originality/value – The relation between the form of the current-voltage characteristic and the distribution profile of the donor concentration in the surface regions of the semiconductor crystallites constituting the intergranular potential barrier is established. The accumulation of donors in the space charge region leads to the increase in the current on the prebreakdown region of the current-voltage characteristic and the reduction of voltage corresponding to the breakdown region beginning of the current-voltage characteristic. The significant role of the interlayer in the formation of current-voltage characteristic of the intergranular potential barrier is shown.

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12

Zola, J. G. "Simple Model of Metal Oxide Varistor for Pspice Simulation." IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems 23, no. 10 (October 2004): 1491–94. http://dx.doi.org/10.1109/tcad.2004.835134.

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13

Lončar, B., M. Vujisić, K. Stanković, and P. Osmokrović. "Stability of Metal-Oxide Varistor Characteristics in Exploitation Conditions." Acta Physica Polonica A 116, no. 6 (December 2009): 1081–84. http://dx.doi.org/10.12693/aphyspola.116.1081.

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14

Makovec, D., D. Kolar, and M. Trontelj. "Sintering and microstructural development of metal oxide varistor ceramics." Materials Research Bulletin 28, no. 8 (August 1993): 803–11. http://dx.doi.org/10.1016/0025-5408(93)90021-5.

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15

Edirisinghe, Mahesh, Raul Montaño, Vernon Cooray, and F. Roman. "Performance Comparison of Varistor Models under High Current Derivative Impulses." International Letters of Chemistry, Physics and Astronomy 11 (September 2013): 40–53. http://dx.doi.org/10.18052/www.scipress.com/ilcpa.11.40.

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Surge protective devices (SPD) testing procedures are mainly performed with standard current pulse types. However, none of these standard current waveforms reproduce the very fast rise time and the large peak current derivatives observed in subsequent return strokes. In the literature there are several mathematical models to represent metal oxide varistor that have been developed based on standard impulse conditions. These models are being used routinely in the analysis of the various electronic circuits under transient conditions. In this paper, a study was conducted to have a performance comparison between the two varistor models, simplified varistor model and Durbak's model, available in the literature under high current derivative impulses. The experiments and simulations were performed on disk type varistors with different diameter sizes, i.e., 20 mm, 10 mm, and 05mm with nominal operating voltage of 230 V. The Roman Generator developed at Uppsala University was used as the high current derivative impulse generator which can produce a peak current up to 1500 A with 10 ns rise time and its rate-of-rise is in the order of 1011 A/s. The results showed that for standard 8/20 µs lightning impulses, simulation results of these models had a good agreement with the experimental data. However, these two models need to be improving in order to improve their performance under high current derivative impulses into the sub-microsecond range.

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16

Sung, Gun Yong, Stuart McKernan, and C. Barry Carter. "Flat interfaces in zinc oxide-based varistor ceramics." Journal of Materials Research 7, no. 2 (February 1992): 474–81. http://dx.doi.org/10.1557/jmr.1992.0474.

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Four types of structurally different, flat interfaces have been observed in ZnO-based varistor ceramics containing metal-oxides additives (Bi, Mn, and Ti) by bright-field and high-resolution imaging in a transmission electron microscope. Orientation relationships have been characterized by selected-area diffraction. The faceting of ZnO grains when in contact with β–Bi2O3 is discussed in relation to the anisotropic growth of the ZnO grains which leads to pronounced faceting parallel to (0001) planes.

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17

Kim, Tae-Ki, Hee-Kyung Shin, and Bok-Hee Lee. "Coordination of Cascaded Metal Oxide Varistor-Based Surge Protective Devices." Journal of the Korean Institute of Illuminating and Electrical Installation Engineers 29, no. 6 (June 30, 2015): 70–77. http://dx.doi.org/10.5207/jieie.2015.29.6.070.

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18

Elayyan, H. S. B., and S. N. Al-Refaie. "Dielectric relaxation assessment of a heat treated metal oxide varistor." IEE Proceedings - Science, Measurement and Technology 150, no. 4 (July 1, 2003): 141–47. http://dx.doi.org/10.1049/ip-smt:20030453.

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19

Zhang, Sa, Zhong Hou Xu, Shi Chen, You Sheng Xu, and Gen Hua Wu. "The Design Principle and Application of Thermally Protected Metal Oxide Varistor TMOV." Advanced Materials Research 472-475 (February 2012): 1851–55. http://dx.doi.org/10.4028/www.scientific.net/amr.472-475.1851.

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Metal oxide varistors referred to as MOV were widely applied due to its excellent non-linear volt-ampere characteristic. In spite of its predominant function and using, MOV is always failed in value due to the increased temperature of MOV itself under an applied external field. The varistors assembly with an fusible alloy type thermal cutoff (called TMOV as follows) was designed in this paper, and it can make MOV avoid over-heat from degradation, failure and thus can prevent from fire hidden trouble, which was confirmed by experiments. It is really a very important technological improvement and breakthrough in over-heat protective field of MOV.

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20

Petrenci, Razvan, Mihaela Frigura-Iliasa, Flaviu M. Frigura-Iliasa, Marius Mirica, Lia Dolga, and Hannelore E. Filipescu. "CAD based design of a high energy absorption metal oxide varistor." Journal of Physics: Conference Series 1195 (April 2019): 012024. http://dx.doi.org/10.1088/1742-6596/1195/1/012024.

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21

Tonkoshkur, Yu A., A. Yu Lyashkov, and A. S. Tonkoshkur. "Isothermal depolarization current in metal-oxide varistor ceramics under various polarizing fields." Journal of Advanced Dielectrics 03, no. 02 (April 2013): 1350016. http://dx.doi.org/10.1142/s2010135x13500161.

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A method of analysis of experimental kinetic dependences of isothermal depolarization currents in metal-oxide varistor ceramics composed of ZnO – Bi 2 O 3– CoO – Sb 2 O 3– SnO 2– MnO – B 2 O 3 has been proposed and tested. The method is based on reconstruction of dependences with the use of the Kohlrausch–Williams–Watt function. Expansion of the distribution and reduction of the average time of dielectric relaxation of the depolarization were found as the magnitude of the polarizing electric field increased. These findings have been interpreted in the framework of the notion of participation in the recharge of localized states more distant from the Fermi level in the crystallites of zinc-oxide ceramics under increased polarizing fields.

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22

Síťař, Vladislav, and Jan Veleba. "Modelling of Metal Oxide Surge Arresters in Simulation Software DYNAST." TRANSACTIONS ON ELECTRICAL ENGINEERING 6, no. 1 (March 30, 2020): 21–27. http://dx.doi.org/10.14311/tee.2017.1.021.

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This paper describes the possibilities for mathematical modelling of gap-less surge arresters in simulation software DYNAST. This tool does not belong to standard modelling softwares in the field of electric power engineering. However, it may provide some key advantages when compared to more frequently used softwares such as EMTP-ATP and MATLAB-Simulink. Description of the metal oxide varistor modelling at temporary and switching overvoltages, fast-front states, and lightning strokes is presented. More information about the defined internal structure of surge arrester models and ways for implementing respective V-I characteristics are provided. To verify the correct behaviour of the models, both slow and fast overvoltage scenarios are simulated and evaluated.

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23

Shimizu, Yasuhiro, Eiichi Kanazawa, Yuji Takao, and Makoto Egashira. "H2 Sensing Properties of Metal Oxide Semiconductors as Varistor-Type Gas Sensors." IEEJ Transactions on Sensors and Micromachines 117, no. 11 (1997): 560–64. http://dx.doi.org/10.1541/ieejsmas.117.560.

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24

Christodoulou, Christos, Vasiliki Vita, Valeri Mladenov, and Lambros Ekonomou. "On the Computation of the Voltage Distribution along the Non-Linear Resistor of Gapless Metal Oxide Surge Arresters." Energies 11, no. 11 (November 6, 2018): 3046. http://dx.doi.org/10.3390/en11113046.

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The voltage distribution along the non-linear resistance of metal oxide surges is of great importance for their proper operation, since the non-uniform potential distribution results in higher thermal stresses of the varistor discs near the high voltage electrode, leading to a faster ageing of the discs at the top and, consequently, a downgrade in arrester effectiveness and reliability or even failures. The current work deals with the examination of the voltage distribution along the non-linear resistance of medium voltage metal oxide gapless surge arresters, using an appropriate computer tool, discussing configuration that improve the voltage distribution. Moreover, the impact of various factors on the voltage distribution is examined. The extracted results can contribute to the more efficient design of modern metal oxide gapless surge arresters, in an effort to ensure their reliable operation to protect the electrical equipment against lightning surges.

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25

Cui, Yan-cheng, Qi-lin Wu, Han-wu Yang, Jing-ming Gao, Song Li, and Cheng-yu Shi. "Experiments of a 100 kV-level pulse generator based on metal-oxide varistor." Review of Scientific Instruments 89, no. 3 (March 2018): 034705. http://dx.doi.org/10.1063/1.5012555.

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26

Hussien Hassan Musa, Mohammed, Ling Fu, Zhengyou He, and Yumin Lei. "Faulty Phase Identification for Transmission Line with Metal Oxide Varistor-protected Series Compensator." Journal of Modern Power Systems and Clean Energy 9, no. 1 (2021): 85–93. http://dx.doi.org/10.35833/mpce.2019.000320.

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27

Scheffzük, Christian, Petra Kluge-Weiss, and Felix Greuter. "Varistor Ceramic: Residual Strain and Texture Analysis by Neutron Time-of-Flight Diffraction." Materials Science Forum 524-525 (September 2006): 781–86. http://dx.doi.org/10.4028/www.scientific.net/msf.524-525.781.

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Strain/stress experiments for characterization of micro- and macro-strain distribution and texture experiments were carried out on a varistor ceramic using neutron-TOF-diffraction. By a radial strain scan, residual strain has been determined on the (1010 ), (0002), (1012), and (1120 ) Bragg reflections of the hexagonal ZnO as well as on the (400) reflections of the cubic spinel Zn7Sb2O12. Residual strain values in the range of -1.5x10-4 (contraction) and 4x10-4 (dilatation) were observed for ZnO, with indications of macro-strains across the cylindrical sample and substantial micro-strains between the different phases. The texture on both phases (ZnO, Zn7Sb2O12) is characterized by a weak, non-ideal fibre texture around the cylinder axis. The results indicate that the texture pattern might coincide with the strain. To our knowledge, these are the first texture and residual strain investigations in metal oxide varistor elements and they will be discussed in detail.

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28

Nyati, S., S. R. Atmuri, D. L. Gordon, and V. Koschik. "Metal oxide varistor to limit dynamic overvoltages at the terminals of an HVDC converter." IEEE Transactions on Power Delivery 3, no. 2 (April 1988): 819–27. http://dx.doi.org/10.1109/61.4322.

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29

He, JinLiang, Jun Hu, BoWen Meng, Bo Zhang, Bin Zhu, ShuiMing Chen, and Rong Zeng. "Requirement of ultra-high voltage GIS arrester to voltage gradient of metal-oxide varistor." Science in China Series E: Technological Sciences 52, no. 2 (October 10, 2008): 450–55. http://dx.doi.org/10.1007/s11431-008-0268-5.

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30

Ivanchenko, A. V., A. S. Tonkoshkur, and S. V. Mazurik. "Application of varistor-posistor structure for protection from overvoltages of photovoltaic cells of solar arrays." Journal of Physics and Electronics 27, no. 1 (October 17, 2019): 79–88. http://dx.doi.org/10.15421/331913.

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The problems of reducing the cost of ensuring the safe operation of solar cells by using low-cost elements of solid-state electronics to protect against overvoltage photovoltaic cells of solar arrays are considered. The results of experimental studies of the use of a varistor-posistor structure based on a metal oxide varistor and PPTC fuses of the PolySwitch type being in thermal contact to prevent overvoltages in series connections of photovoltaic cells are presented. General schemes for using the considered solid-state structure to limit the indicated constant overvoltages are given and justified. The requirements to the parameters of this structure are determined and experimentally verified. It is shown that such a device makes it possible to limit the long-term constant overvoltages that occur in photovoltaic arrays at the level of photovoltaic cells in the case of their malfunction or shadowing, which can lead to fire hazard and other “abnormal” situations during the operation of solar electric energy sources.

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31

Tonkoshkur, Alexander, and Alexander Ivanchenko. "ALGORITHM FOR SOFTWARE IMPLEMENTATION OF DESIGNING OVERVOLTAGE PROTECTION IN PHOTOVOLTAIC MODULES OF SOLAR ARRAYS USING A VARISTOR-POSISTOR STRUCTURE." System technologies 1, no. 126 (March 27, 2020): 124–43. http://dx.doi.org/10.34185/1562-9945-1-126-2020-14.

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The use of modern hardware and software design allows to effectively solve a number of problems associated with the development of various technical devices. The specificity of this approach is the development of algorithms with the capabilities of dynamic correction of the design process with the participation of the user. The algorithm of the software implementation of designing protection circuits against electrical overloads in photovoltaic modules of solar arrays using a voltage limiting device based on metal oxide varistor and posistor of the PolySwitch type being in thermal contact is described in this paper. The algorithm provides for determining the optimal technical parameters of the voltage limiting device (minimum resistance and tripping current of the posistor element, classification voltage and non-linearity coefficient of the varistor element) for the operation of photovoltaic module, which is in the state of lighting in the absence and presence of faulty, degraded, or shaded photovoltaic cells.

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32

Ri, Chol-Nam, Chol-Jun Kim, Song-Gol Kim, and Myong-Hak Kim. "Synthesis of the Composite Additive Fine Powders for ZnO Varistor by Low-Temperature Combustion." Nano 14, no. 05 (May 2019): 1950053. http://dx.doi.org/10.1142/s179329201950053x.

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The composite oxide additive containing Mn, Ni, Cr and Co elements for the ZnO varistor was successfully synthesized through the low-temperature combustion synthesis approach. The combustion reaction was carried out using nitrate mixtures of Mn, Ni, Cr and Co as oxidants and hydrazine as fuel. Herein, hydrazine acts as a bidentate bridge ligand, and it forms a complex with metal nitrate. Controlling the pH value of reactant solution by adding the hydrazine had a considerable effect on the combustion characteristics of the precursor and the final synthesized powder properties. The results of the XRD, FT-IR, SEM and TEM analysis indicated that the suitable pH value for synthesizing the composite additive powder with fine grain size and good crystallinity was 7. The precursor prepared at [Formula: see text] exhibited steady and slow combustion characteristics, and its yield rate achieved ca. 100%. With this method, the composite additive fine powder suitable for improvement of the electrical characteristics of ZnO varistor can be synthesized simultaneously on a large scale.

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33

Tanaka, Tokuya, Yoshihiro Baba, Yoshimasa Tsujimoto, and Naoyuki Tsukamoto. "Simplified Thermal Computation of a Metal Oxide Varistor Element under a Lightning Impulse Current Injection." IEEJ Transactions on Electrical and Electronic Engineering 16, no. 6 (April 25, 2021): 879–81. http://dx.doi.org/10.1002/tee.23375.

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34

Kim, Sung-Yeon, Jeong-Su Park, and Wang-Sang Lee. "Development and Verification of Indirect Lightning-Induced Transient Protection Circuit for Avionics System." Applied Computational Electromagnetics Society 36, no. 6 (August 6, 2021): 670–75. http://dx.doi.org/10.47037/2020.aces.j.360608.

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In this paper, an indirect lightning-induced transient protection circuit for avionics system is proposed, and its effectiveness is verified. The proposed circuit consists of a metal oxide varistor (MOV), a transient voltage suppression (TVS) diode, and a resistor. Compared with the conventional circuits (MOV or TVS diode), the improved noise suppression of the proposed circuit against indirect lightning strikes are experimentally verified in accordance with radio technical commission for aeronautics (RTCA) DO-160G Sec. 22. The highest attenuation levels of indirect lightning strike WF5A reference voltage and current signals are approximately 91.0% and approximately 98.4% for the input lightning signals, respectively.

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35

Kim, Young Sun. "Failure Prediction of Metal Oxide Varistor Using Nonlinear Surge Look-up Table Based on Experimental Data." Transactions on Electrical and Electronic Materials 16, no. 6 (December 25, 2015): 317–22. http://dx.doi.org/10.4313/teem.2015.16.6.317.

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36

Tanaka, Tokuya, Ryosuke Tsuge, Yoshihiro Baba, Yoshimasa Tsujimoto, and Naoyuki Tsukamoto. "An Approximate Mathematical Expression for Nonlinear Resistive Properties of Metal Oxide Varistor Elements for FDTD Simulations." IEEE Transactions on Electromagnetic Compatibility 62, no. 6 (December 2020): 2638–42. http://dx.doi.org/10.1109/temc.2020.2983200.

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37

Cui, Yancheng, Chengyu Shi, Hanwu Yang, Jingming Gao, Song Li, and Qilin Wu. "Preliminary study on pulse width adjustable pulse generator based on the magnetic switch and metal-oxide varistor." AIP Advances 8, no. 11 (November 2018): 115317. http://dx.doi.org/10.1063/1.5026837.

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38

Hertleer, Carla, Jeroen Meul, Gilbert De Mey, Simona Vasile, Sheilla A. Odhiambo, and Lieva Van Langenhove. "Mathematical Model Predicting the Heat and Power Dissipated in an Electro-Conductive Contact in a Hybrid Woven Fabric." Autex Research Journal 20, no. 2 (May 13, 2020): 133–39. http://dx.doi.org/10.2478/aut-2019-0013.

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AbstractElectro-conductive (EC) yarns can be woven into a hybrid fabric to enable electrical current to flow through the fabric from one component A to another component B. These hybrid fabrics form the bases of woven e-textiles. However, at the crossing point of an EC yarn in warp and in weft direction, there is a contact resistance and thus generation of heat may occur in this area. Both phenomena are inseparable: if the contact resistance in the EC contact increases, the generated heat will increase as well. Predicting this electrical and thermal behavior of EC contacts in hybrid woven fabrics with stainless steel yarns is possible with a mathematical model based on the behavior of a metal oxide varistor (MOV). This paper will discuss in detail how this can be achieved.

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Stracqualursi, Erika, Rodolfo Araneo, Giampiero Lovat, Amedeo Andreotti, Paolo Burghignoli, Jose Brandão Faria, and Salvatore Celozzi. "Analysis of Metal Oxide Varistor Arresters for Protection of Multiconductor Transmission Lines Using Unconditionally-Stable Crank–Nicolson FDTD." Energies 13, no. 8 (April 24, 2020): 2112. http://dx.doi.org/10.3390/en13082112.

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Surge arresters may represent an efficient choice for limiting lightning surge effects, significantly reducing the outage rate of power lines. The present work firstly presents an efficient numerical approach suitable for insulation coordination studies based on an implicit Crank–Nicolson finite difference time domain method; then, the IEEE recommended surge arrester model is reviewed and implemented by means of a local implicit scheme, based on a set of non-linear equations, that are recast in a suitable form for efficient solution. The model is proven to ensure robustness and second-order accuracy. The implementation of the arrester model in the implicit Crank–Nicolson scheme represents the added value brought by the present study. Indeed, its preserved stability for larger time steps allows reducing running time by more than 60 % compared to the well-known finite difference time domain method based on the explicit leap-frog scheme. The reduced computation time allows faster repeated solutions, which need to be looked for on assessing the lightning performance (randomly changing, parameters such as peak current, rise time, tail time, location of the vertical leader channel, phase conductor voltages, footing resistance, insulator strength, etc. would need to be changed thousands of times).

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40

Tanaka, Tokuya, Yoshihiro Baba, Yoshimasa Tsujimoto, and Naoyuki Tsukamoto. "FDTD Electromagnetic and Thermal Simulation of a Metal Oxide Varistor Element Considering the Temperature Dependence of Its Resistivity." Electricity 2, no. 2 (May 4, 2021): 158–67. http://dx.doi.org/10.3390/electricity2020010.

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Electromagnetic fields and the heat of a metal oxide varistor (MOV), in which a lightning impulse current flows, are calculated using the finite-difference time-domain (FDTD) method. The MOV is represented with small rectangular parallelepiped cells, each of which has a resistivity dependent on electric field and temperature. For this purpose, the expression of resistivity as a function of the electric field, proposed previously, is extended to include the dependence on temperature. The temperature dependence is based on voltages across an MOV for impulse currents of 0.5 to 10 kA at temperatures in a range from about 300 to 900 K, measured by Andoh et al. (2000). FDTD-calculated waveform of voltage across the MOV agrees well with the corresponding measured one for a short impulse current with a magnitude of about 4 kA and a duration of about 30 μs. In addition, the temperature on the surface of the MOV agrees well with the corresponding measured one. Further, calculations are carried out for the MOV with a nonuniform resistivity distribution, which roughly simulates deterioration or degradation of the MOV, for a long duration current having a magnitude of 5 kA. The proposed expression of resistivity, given as a function of electric field and temperature, is useful in studying electro-thermal calculations, which can provide insights into causes of MOV damages.

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Cui, Yancheng, Qilin Wu, Hanwu Yang, Jingming Gao, Song Li, and Chengyu Shi. "A Method of Creating the High-Voltage Circuit Model of Metal–Oxide Varistor for the Simulation of Square Pulse Forming." IEEE Transactions on Circuits and Systems II: Express Briefs 67, no. 3 (March 2020): 526–30. http://dx.doi.org/10.1109/tcsii.2019.2915246.

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42

Ghassemi, F., J. Goodarzi, and A. T. Johns. "Method to improve digital distance relay impedance measurement when used in series compensated lines protected by a metal oxide varistor." IEE Proceedings - Generation, Transmission and Distribution 145, no. 4 (1998): 403. http://dx.doi.org/10.1049/ip-gtd:19982002.

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43

Soni, K. K., J. Hwang, V. P. Dravid, T. O. Mason, and R. Levi-Setti. "Microchemistry of ZnO Varistors." Proceedings, annual meeting, Electron Microscopy Society of America 50, no. 2 (August 1992): 1694–95. http://dx.doi.org/10.1017/s0424820100133102.

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ZnO varistors are made by mixing semiconducting ZnO powder with powders of other metal oxides e.g. Bi2O3, Sb2O3, CoO, MnO2, NiO, Cr2O3, SiO2 etc., followed by conventional pressing and sintering. The non-linear I-V characteristics of ZnO varistors result from the unique properties that the grain boundaries acquire as a result of dopant distribution. Each dopant plays important and sometimes multiple roles in improving the properties. However, the chemical nature of interfaces in this material is formidable mainly because often trace amounts of dopants are involved. A knowledge of the interface microchemistry is an essential component in the ‘grain boundary engineering’ of materials. The most important ingredient in this varistor is Bi2O3 which envelopes the ZnO grains and imparts high resistance to the grain boundaries. The solubility of Bi in ZnO is very small but has not been experimentally determined as a function of temperature.In this study, the dopant distribution in a commercial ZnO varistor was characterized by a scanning ion microprobe (SIM) developed at The University of Chicago (UC) which offers adequate sensitivity and spatial resolution.

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S, Pranupa, Kiran Kumar B M, and S. Nagaraja Rao. "Detection of Rotating Diode Failure Condition & its Protection in Brushless Alternator." International Journal of Engineering & Technology 7, no. 4.24 (November 27, 2018): 26. http://dx.doi.org/10.14419/ijet.v7i4.24.21765.

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Brushless excitation system is widely used in large capacity synchronous generators since it removes the usage of commutator, brushes and slip rings, hence reduces the losses, maintenance and increases reliability. Rotating Rectifier Assembly (RRA) is the main part of brushless alternator. Due to ageing phenomenon and continuous process regime, diodes in rotating rectifier can fail either due to Open Circuit (OC) or Short Circuit (SC), which overloads the exciter and hence the alternator can no longer run securely. If such condition is prolonged, the Automatic Voltage Regulator (AVR) as well as the exciter windings can be damaged.This paper presents two different methods of diode failure detection in brushless alternators. First method uses an algorithm based on output voltage and the second uses the ripple factor of the exciter field current. Diode failure condition is detected for different type of loads connected to 4 kVA, 380 V, 50 Hz, 4 poles generator with 14 pole exciter (brushless alternator) and the results are verified using MATLAB/Simulink. Also, the protection schemes for rotating diode assembly as well as exciter field windings are presented using Metal Oxide Varistor (MOV) and Discharge Resistor.

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45

Rezaei, Saeed, Mojtaba Khederzadeh, and Majid Gandomkar. "A Fault Detection Technique for Series-compensated Lines by TCSC during Power Swing." International Journal of Applied Power Engineering (IJAPE) 7, no. 1 (April 1, 2018): 40. http://dx.doi.org/10.11591/ijape.v7.i1.pp40-51.

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The performance of a distance relay is very susceptible to power swing. In order to avoid generating unwanted trip in such condition, a power swing block function (PSB) is used in distance relays. However, if a fault occurs in power swing condition, the relay should distinguish the fault from power swing and generate trip rapidly. Detection a fault in a series-compensated line by Series Capacitor (SC) during the power swing is more complicated than in an uncompensated line due to complex transients generated by series capacitor and the Metal–Oxide Varistor (MOV) operation. In a series-compensated line by TCSC, it is further complicated due to nonlinear variation of compensation level during power swing and fault, moreover, non-unique application mode of TCSC for different faults which is dependent on fault current. This paper examines a method based on negative sequence current to detecting all types of fault during power swing in a series-compensated line by TCSC. The method is tested for different TCSC-compensated power systems include SMIB and 9-bus 3-machine systems. Different types of faults, i.e., symmetrical, asymmetrical and high resistance faults occurring during a power swing are simulated by MATLAB/SIMULINK to examine the algorithm.

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46

Janiczek, Tomasz, Dorota Nowak, Witold Mielcarek, and Krystyna Prociów. "Equivalent Model of Modified Bismuth Oxides Described by Fractional Derivatives." Key Engineering Materials 336-338 (April 2007): 676–79. http://dx.doi.org/10.4028/www.scientific.net/kem.336-338.676.

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Metal oxide modified Bi2O3 finds the application in metal oxide varistors and as ionic conductors. Electrical properties of MeO-modified Bi2O3 change with MeO modifier and sintering temperature. In this paper we report how to predict Bi2O3 electrical properties using simulation model. Measurements of the electrical response of the modified Bi2O3 oxides were carried out using the impedance spectroscopic technique. As a result an equivalent model of electrical behaviour of modified Bi2O3, described by fractional derivates was proposed. To test the model, the series of simulation were run on computer, and after subjecting the results to verification the equivalent parameters of electrical circuit were determined. Model was elaborated with the view of facilitating the research on metal oxide ionic conductors and varistors.

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47

Einzinger, R. "Metal Oxide Varistors." Annual Review of Materials Science 17, no. 1 (August 1987): 299–321. http://dx.doi.org/10.1146/annurev.ms.17.080187.001503.

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48

Ludin, Gul Ahmad, Mohammad Amin Amin, Hidehito Matayoshi, Shriram S. Rangarajan, Ashraf M. Hemeida, Hiroshi Takahashi, and Tomonobu Senjyu. "Solid-State DC Circuit Breakers and Their Comparison in Modular Multilevel Converter Based-HVDC Transmission System." Electronics 10, no. 10 (May 18, 2021): 1204. http://dx.doi.org/10.3390/electronics10101204.

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This paper proposes a new and surge-less solid-state direct current (DC) circuit breaker in a high-voltage direct current (HVDC) transmission system to clear the short-circuit fault. The main purpose is the fast interruption and surge-voltage and over-current suppression capability analysis of the breaker during the fault. The breaker is equipped with series insulated-gate bipolar transistor (IGBT) switches to mitigate the stress of high voltage on the switches. Instead of conventional metal oxide varistor (MOV), the resistance–capacitance freewheeling diodes branch is used to bypass the high fault current and repress the over-voltage across the circuit breaker. The topology and different operation modes of the proposed breaker are discussed. In addition, to verify the effectiveness of the proposed circuit breaker, it is compared with two other types of surge-less solid-state DC circuit breakers in terms of surge-voltage and over-current suppression. For this purpose, MATLAB Simulink simulation software is used. The system is designed for the transmission of 20 MW power over a 120 km distance where the voltage of the transmission line is 220 kV. The results show that the fault current is interrupted in a very short time and the surge-voltage and over-current across the proposed breaker are considerably reduced compared to other topologies.

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Tan, Daniel, Karim Younsi, Yingneng Zhou, Patricia Irwin, and Yang Cao. "Nano-enabled metal oxide varistors." IEEE Transactions on Dielectrics and Electrical Insulation 16, no. 4 (August 2009): 934–39. http://dx.doi.org/10.1109/tdei.2009.5211836.

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50

YORDANOV, S. P. "Frequency limitation of metal-oxide varistors." International Journal of Electronics 73, no. 2 (August 1992): 301–6. http://dx.doi.org/10.1080/00207219208925668.

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