Zhi Jin Zhang, Matthew Bosworth, Chunmeng Xu, Andrew Rockhill, Peter Zeller, Maryam Saeedifard, Lukas Graber, Michael Steurer,
Varistors are widely used in dc circuit breaker (DCCB) application as fault energy absorption elements, which is not an application the varistors are originally designed for. The fault energy stress adversely impacts the varistor lifetime, thus affecting DCCB reliability and performance. This article presents two methods for choosing the appropriate varistor type and arrangement in a DCCB by linking 1) varistor lifetime and 2) DCCB component- and system-level ... and proposes an integer programming problem to optimize varistor lifetime. Both procedures are applied to the selection ...
Tópico(s): Power System Reliability and Maintenance
2022 - Institute of Electrical and Electronics Engineers | IEEE Transactions on Power Electronics
Tian Tian, Liaoying Zheng, Matejka Podlogar, Huarong Zeng, Slavko Bernik, Kunqi Xu, Xuezheng Ruan, Xun Shi, Guorong Li,
... The power-law current–voltage relationship of a varistor is one such example. An excellent example of ... current–voltage relationship exhibited by Bi2O3-doped ZnO varistor ceramics, which are the cornerstone of commercial varistor materials for overvoltage protection. Here, we report on a sustainable, ZnO-based varistor ceramic, without the volatile Bi2O3, that is based on Cr2O3 as the varistor former and oxides of Ca, Co, and Sb ... making it superior to state-of-the-art varistor ceramics. The results provide insights into the design ...
Tópico(s): Multiferroics and related materials
2021 - American Chemical Society | ACS Applied Materials & Interfaces
Zumret Topčagić, Miha Mlakar, Thomas E. Tsovilis,
The energy absorption capability of metal-oxide varistors, decidedly influenced by the electrothermal processes occurring within their microstructures, is a vital parameter for the effective surge protection. This paper proposes a ... of the electrothermal phenomena occurring in metal-oxide varistors. The model is based on a 3D representation of the varistor's polycrystalline microstructure and the finite element method ... of the proposed model, the interdependence of the varistor's energy absorption capability, nonuniform current conduction, and ...
Tópico(s): Electrical Fault Detection and Protection
2019 - Institute of Electrical and Electronics Engineers | IEEE Transactions on Power Delivery
Zumret Topčagić, Thomas E. Tsovilis, Dejan Križaj,
Nonuniform current distribution inside varistor ceramics is a key factor influencing its performance and failures. Therefore understanding, modeling and predicting of current distribution in varistor ceramics is of crucial significance. This paper proposes ... of nonuniform electric current distribution inside zinc oxide varistors. A numerical model is based on physical modeling of the varistor's grain-structured geometry presented by Voronoi network ... understanding and predicting nonuniform current distribution in the varistor. In order to properly establish a FEM model ...
Tópico(s): ZnO doping and properties
2018 - Elsevier BV | Electric Power Systems Research
J. Kulawik, D. Szwagierczak, Agata Skwarek,
... study was to develop fabrication procedure of multilayer varistors based on doped ZnO and to investigate their ... O 3 were used for tape casting of varistor tapes. Multilayer varistors were prepared by stacking of several green sheets ... examine the microstructure and elemental composition of the varistors. Current-voltage characteristics were measured in the temperature ... desired compact and fine-grained microstructure of multilayer varistors and nonlinear current-voltage characteristics were attained as ...
Tópico(s): Gas Sensing Nanomaterials and Sensors
2017 - Emerald Publishing Limited | Microelectronics International
S. Hirose, Hideaki Niimi, Keisuke Kageyama, Hideharu Ieki, Takahisa Omata, Shinya Otsuka‐Yao‐Matsuo,
Degradation of potential barriers in ZnO-based varistors due to the electrostatic discharge (ESD) was investigated using scanning probe microanalysis and capacitance-time and isothermal capacitance transient spectroscopies. Pr6O11-ZnO (Pr-ZnO) varistors exhibit excellent ESD withstand capability compared with Bi2O3-ZnO (Bi-ZnO) varistors. After the application of ESD, asymmetrically degraded double ... observed in both Pr-ZnO and Bi-ZnO varistors, and the Schottky barrier in Bi-ZnO was ... destroyed. The potential barriers of both types of varistors can respond to an ESD pulse, whose rise ...
Tópico(s): Semiconductor materials and devices
2012 - American Institute of Physics | Journal of Applied Physics
Shengtao Li, Tuo Zhang, Qifeng Huang, Weiwei Li, Fengyan Ni, Jianying Li,
... this paper, a new insulation system of ZnO varistor ceramic– $ \hbox{Al}_{2}\hbox{O}_{3}$ ceramic-ZnO varistor ceramic insulators (defined as A-B-A insulators) ... changing the conductivity and permittivity of the ZnO varistor ceramic layer of the A-B-A insulators. ... influences of the conductivity and permittivity of ZnO varistor ceramics on the dc and impulse surface flashover ... decrease of the dc conductivity of the ZnO varistor ceramic layer and is improved by 81% compared ... voltage characteristics of layer A, i.e., ZnO varistor ceramics. Additionally, the impulse surface flashover voltage first ...
Tópico(s): Power Transformer Diagnostics and Insulation
2010 - Institute of Electrical and Electronics Engineers | IEEE Transactions on Plasma Science
Shuai Wan, Wenzhong Lü, Xiao‐Chuan Wang,
... Co 2 O 3 –MnCO 3 (ZBTCM)‐based varistors have been investigated. The varistor ceramic with the addition of >2 wt% BiBF ... achieved. SEM revealed that the microstructure of the varistor ceramics with 2 wt% BiBF is uniform, with ... ZnO–Bi 2 O 3 –TiO 2 ‐based varistor phase compositions were detected for all varistor ceramics but the formation of a secondary phase, ... role in improving the electrical properties of the varistor ceramics. However, a large amount will be detrimental. Optimum properties were exhibited for the varistor ceramics with 2 wt% BiBF sintered at 900° ...
Tópico(s): Dielectric properties of ceramics
2010 - Wiley | Journal of the American Ceramic Society
Jinliang He, She Chen, Rong Zeng, Xiangfeng Liang, Zhicheng Guan, Sang-Kyoo Han, H.-G. Cho,
Analyzing the nonuniformity of electrical parameters of ZnO varistors is useful to select and coordinate the ZnO varistors in parallel operation and improve the protection capability ... impulse residual voltage of commercial low-voltage ZnO varistors were estimated by statistic analysis in this paper. ... mA dc voltage and impulse residual voltage, ZnO varistors were verified conforming to the Minimum Gobble Distribution ... The nonuniform phenomena of electrical parameters of ZnO varistors were simulated by Voronoi network. The current overload ...
Tópico(s): Lightning and Electromagnetic Phenomena
2005 - Institute of Electrical and Electronics Engineers | IEEE Transactions on Power Delivery
Aran Rafferty, Yurii K. Gun’ko, Ramesh Raghavendra,
... this work was to co-fire crack-free varistor-ferrite ceramic multilayers fabricated via a dry pressing ... Multilayers were sintered using a standard industrial grade varistor sintering regime.Sinter shrinkages of both varistor and ferrite materials were measured using dilatometry and showed that the varistor shrunk significantly more than the ferrite material.X- ... microscopy observations of the dry-pressed co-fired varistor-ferrite revealed vertical cracking in the ferrite due ... interlayer in the ratio 50:50, between the varistor and ferrite materials, a crack-free multilayer structure ...
Tópico(s): Electromagnetic wave absorption materials
2003 - Elsevier BV | Journal of the European Ceramic Society
Yasuyuki Shirai, Yuji Miyato, M. Taguchi, M. Shiotsu, H. Hatta, Shin Muroya, M. Chiba, T. Nitta,
... SCFCL) of the transformer type with a ZnO varistor (metal oxide varistor) in parallel was investigated to determine the effects of the ZnO varistor as an over-voltage suppressor for the SCFCL. ... current limiting operation of the SCFCL with ZnO varistor in parallel are shown. It was confirmed that ... the SCFCL can be successfully suppressed by ZnO varistor. Current limiting and recovery characteristics of the SCFCL with a ZnO varistor are investigated and discussed. The trigger current level ... the SCFCL is not affected by the ZnO varistor. The recovery time is a little longer with ...
Tópico(s): High-Voltage Power Transmission Systems
2003 - IEEE Council on Superconductivity | IEEE Transactions on Applied Superconductivity
Yasuhiro Shimizu, Feng‐Cang Lin, Yuji Takao, Makoto Egashira,
... properties of two series of porous ZnO‐based varistors has been investigated; the two varistor series are with and without 5.0 mol% ... terms of microstructural and crystallographical changes of the varistors. The addition of Y 2 O 3 to the base ZnO varistors without Cr 2 O 3 results in a ... Cr 2 O 3 to the base ZnO varistor also has been confirmed to be effective for ... Y 2 O 3 to the ZnO‐based varistors that contain 5.0 mol% Cr 2 O ... grain size remains almost unchanged. This series of varistors also exhibits the highest sensitivity with 0.25 ...
Tópico(s): Analytical Chemistry and Sensors
1998 - Wiley | Journal of the American Ceramic Society
A novel technique for preparing ZnO varistor powder is described. It involves preparation of gel by adding citric acid to nitrate solution of varistor constituents. The gel on subsequent calcination forms submicron reactive varistor powder that exhibits the homogeneity and stoichiometric control ... to comprise crystallite of submicron size. High field varistors with good nonlinear coefficient result from sintering at ... The high value of nonlinear coefficient of the varistor sample can be attributed to the more uniform ...
Tópico(s): Nonlinear Optical Materials Research
1997 - Elsevier BV | Materials Research Bulletin
Mohammad Maleki Shahraki, Pezhman Mahmoudi, Mehdi Abdollahi, Touradj Ebadzadeh,
In this research, fine-grained SnO2-based varistors with a simple microstructure and the mean grain size of 0.8 µm were obtained by the microwave sintering method. The breakdown electric field measured for these varistors was 12 kV/cm that is 3 times higher than the conventional-sintered varistors. The high nonlinear coefficient (60) and low leakage ... µA/cm2) were achieved in fine-grained SnO2 varistors. The fine-grained SnO2 varistors appropriately clamped pulse current surges and the calculated value of the clamping voltage ratio of these varistors was 2. The excellent electrical properties and protective ...
Tópico(s): Thin-Film Transistor Technologies
2018 - Elsevier BV | Materials Letters
A.I. Ivon, A.B. Glot, R.I. Lavrov, Zhenya Lu,
... commercial ZnO-based and laboratory-made SnO2-based varistor ceramics exhibiting highly nonlinear current–voltage characteristics at ... exponential voltage pulse. At 295 K commercial ZnO varistors exhibit some lower values of the grain resistivity ... values 2.4–28 Ω сm for SnO2 varistors. Respectively, the high-current nonlinearity coefficients for ZnO varistors are higher than for SnO2 varistors. The capacitive currents did not affect the obtained ... the range of Ohm's law) for SnO2 varistors (0.82–0.98 eV) is larger than ...
Tópico(s): Ga2O3 and related materials
2014 - Elsevier BV | Journal of Alloys and Compounds
Chunlong Zhang, Chunying Li, Dongbo Lv, Hao Zhu, Hongyan Xing,
... waveform parameters on the aging characteristics of ZnO varistor, the aging rate and surface temperature rise of ZnO varistor under the impact of multi-pulse current were ... decisive role in the aging rate of ZnO varistor. The greater the number of pulses and the ... the higher the temperature rise of the ZnO varistor and the faster the aging rate, the more ... damage. The surface temperature distribution of the ZnO varistor under multi-pulse is not uniform, and the ... is established. The aging mechanism of the ZnO varistor under a multi-pulse lightning stroke was revealed ...
Tópico(s): Earthquake Detection and Analysis
2020 - Multidisciplinary Digital Publishing Institute | Electronics
ZnO varistors are key elements in metal oxide arrestors(MOA).The overvoltage level of power systems and the insulation ... directly determined by the electrical properties of ZnO varistors.With the construction of ultra high voltage(UHV) ... required to be elevated.It is claimed that varistors utilized in UHV arrestors should be with high ... capability and high stability,compared with traditional MOA varistors.According to reported literatures,ZnO varistors used in UHV metal oxide arrestors possess voltage ...
Tópico(s): Smart Grid and Power Systems
2011 - Science Press | Gao dianya jishu
J. Warycha, Witold Mielcarek, Grzegorz Lesiuk,
... possibility of eliminating of electrically inactive areas from varistor body with maintaining varistor electrical parameters can be achieved by modifying Bi2O3 ... as not to form electrically inactive areas in varistor. It has been proven that modification of Bi2O3 ... other MeO results in significant changes in the varistor structure, thereby gaining the uniform distribution of the ... and shivered. Modified Bi2O3 was added to the varistor bulk in quantities of 1.0, 0.3, ... 2 and 0.1 mol% to study the varistor properties. The best results were obtained for the ...
Tópico(s): Transition Metal Oxide Nanomaterials
2021 - Elsevier BV | Engineering Failure Analysis
Chunlong Zhang, Hongyan Xing, Chunying Li, Ran Cai, Dongbo Lv,
In view of the problem that ZnO varistors are often subjected to thermal breakdown and deterioration due to lightning strikes in low-voltage power distribution systems, this article used a 8/ ... 50 ms to perform shock experiments on ZnO varistors. SEM scanning electron microscope and an XRD diffractometer ... change of the crystalline phase material of ZnO varistor under the action of a multi-pulse current. The damage mechanism of ZnO varistor under the multi-pulse current was studied at ... average impact life of different types of ZnO varistor is significantly different. It was found that the ...
Tópico(s): Combustion and Detonation Processes
2020 - Multidisciplinary Digital Publishing Institute | Energies
S. Anas, K. V. Mahesh, V. Jobin, Sujayakumar Prasanth, S. Ananthakumar,
... synthesis and development of high energy field ZnO varistors. The key aspect of the study involves the ... pH selective precipitation and reflux method. High field varistors were developed out of these crystalline nanofillers by ... them as fillers to the micron sized commercial varistor powder. A systematic investigation of the microstructural changes of the nanofiller added varistor samples were carried out under step-sintering and ... micro counterparts. The influence of nanofillers in the varistor powder packing, grain structure refinement, grain size reduction ...
Tópico(s): Advanced ceramic materials synthesis
2013 - Royal Society of Chemistry | Journal of Materials Chemistry C
B. Lončar, Miloš Vujisić, Koviljka Stanković, P. Osmokrović,
Wide-spread use of metal-oxide varistors for non-linearity over-voltage protection results in a variety of possible working conditions.It is therefore essential to have a thorough ... variation, aging and radiation exposure on metal-oxide varistors characteristics were investigated in this paper.Stable and ... to overall system reliability.Behaviour of metal-oxide varistors in the temperature range from -50 • C to ... consecutive double exponential over-voltage pulses to the varistors.Resistance of metal-oxide varistors to the radiation ...
Tópico(s): Graphite, nuclear technology, radiation studies
2009 - Polish Academy of Sciences | Acta Physica Polonica A
... absorption capability is a key parameter for ZnO varistors. This paper discusses the nonuniformity of energy absorption capabilities of ZnO varistors. With experiment results, we show that energy absorption capabilities of ZnO varistors can be highly scattered, for different commercial varistors, and for the same varistors under diverse current waves. We explain this nonuniformity ... microscopic circuit and heat transfer models of ZnO varistors. How the applied current, the nonuniformity of microstructure, ...
Tópico(s): Gas Sensing Nanomaterials and Sensors
2007 - Institute of Electrical and Electronics Engineers | IEEE Transactions on Power Delivery
Jinfeng Wang, Hong‐Cun Chen, Wenbin Su, Guo‐Zhong Zang, Biao Wang, Ruwei Gao,
... and electrical properties of (Co, Ta)-doped SnO2 varistors upon the addition of SrCO3 was investigated. The threshold electric field of the SnO2-based varistors increased significantly from 318 to 3624 V/mm, the relative dielectric constants of the SnO2-based varistors decreased greatly from 1509 to 69 as SrCO3 ... the SnO2 grains from conglomerating into large particles. Varistors were found to have superhigh threshold voltage and ... large nonlinear coefficient qualify the Sr-doped SnO2 varistor as an excellent candidate in use for high ...
Tópico(s): Transition Metal Oxide Nanomaterials
2005 - Elsevier BV | Journal of Alloys and Compounds
Yasuhiro Ohbuchi, Toshio Kawahara, Yoichi Okamoto, Jun Morimoto,
... states in the Pr- and Bi-type ZnO varistors. Three bulk traps (B1 ′ , B1 and B2) were ... The distribution of B1' in Bi-type ZnO varistors was different from that of B1 ′ in Pr-type ZnO varistors. This indicates that B1' is caused by the ... process. Four interface states in Bi-type ZnO varistors (T0, T1a, T1b and T2) and two interface states in Pr-type ZnO varistors (T0 and T1) were clearly found. T2 was only detected for Bi-type ZnO varistors and had a slower time constant with broadening ... in terms of understanding the characteristics of ZnO varistors.
Tópico(s): X-ray Diffraction in Crystallography
2001 - Institute of Physics | Japanese Journal of Applied Physics
Takeo Hyodo, Eiichi Kanazawa, Yuji Takao, Yasuhiro Shimizu, Makoto Egashira,
Hydrogen sensing properties and mechanism of Nb2O5 varistors mixed with Bi2O3 (0-16.7 mol %) were investigated in the H2 concentration range of 0.2-2.0 % at 400-700 °C. ... 400 °C than the ZnO- and SnO2-based varistors reported before. The H2 sensitive properties of a Nb2O5 varistor were improved by the addition of Bi2O3 up to 5.0 mol % and the Nb2O5 varistor mixed with 1.0 mol % Bi2O3 exhibited the highest sensitivity at 400 °C among the varistors tested. However, further addition of Bi2O3 resulted in ... of the varistols. Resistances of the Nb2O5-Bi2O3 varistors were decomposed into four components, (i) bulk resistance ( ...
Tópico(s): Analytical Chemistry and Sensors
2000 - The Electrochemical Society of Japan | Electrochemistry
Hsin Wang, M. Bartkowiak, F. A. Modine, Ralph B. Dinwiddie, L. A. Boatner, G. D. Mahan,
... was used to monitor the heating of ZnO varistors by electrical transients. On a macroscopic scale (e.g., 10 mm), heating in large varistor blocks (i.e., diameter of 42 mm) was ... e.g., 1 mm), the heating in small varistor disks (e.g., diameter of 10 mm) was ... e.g., 10 μm), the heating in thin varistor slices (e.g., thickness of 100 μm) was ... to permit temperature differences that could cause a varistor failure. Current localization and nonuniform heating on an ... are shown to be significant only in small varistors, whereas destructive failures (puncture and cracking) of large ...
Tópico(s): Thin-Film Transistor Technologies
1998 - Wiley | Journal of the American Ceramic Society
E. Sonder, Lionel M. Levinson, W. Katz,
... the mechanisms involved in the degradation of ZnO varistors at elevated temperatures in reducing atmospheres. The electrical ... the degradation sensitivity depends to some extent on varistor composition but can be highly variable for different varistors of the same formulation and even within a given varistor sample. The SIMS data indicate that oxygen ions are highly mobile when varistors are heated above 290 °C, and it is proposed that flaws, such as microcracks in the varistors, act as conduits for oxygen at elevated temperatures. ...
Tópico(s): Ion-surface interactions and analysis
1985 - American Institute of Physics | Journal of Applied Physics