Papers by Keyword: Leakage Current

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Authors: Xuan Li, Na Bai, Zhan Fang Wu
Abstract: A new bitline sense amplifier (SA) for improving performance in the presence of current compensation is analyzed. The proposed scheme utilizes a new leakage current compensation circuit, resulting in a 42.9% reduction in the delay from bitline discharge to the date been read out. Thus, this is very important for higher performance application, especially under advanced technology process.
Authors: Yan Chun Xu, Guo Xun Chen
Abstract: It is difficult to detect and judge a weak electric shock signals in the leakage current accurate in the low-voltage power grid .A novel chaotic detection of the electric shock current and Lyapunov exponent is introduced in this paper .Electric shock current component is extracted according to the characteristics that chaotic system’s bifurcation action from chaotic state is sensitive to the weak signals and immune to noise .The largest Lyapunov exponent is proposed as the judgment criterion of phase transition of chaotic system. It can automatically recognize the critical state before and after electric shock.
Authors: Song Gao, Feng Bo Tao, Zhen Yao Liu, Zhi Cheng Zhou, Li Ming Wang
Abstract: The industrial development has been aggravating the atmospheric pollution increasingly. The pollution flashover has always been one of the most important problems that bother the development of electric power system in China. The key to prevent the happening of pollution flashover accident is that the electric power operation department can timely and correctly master the condition of external insulation of insulator string in operation to take measures before the happening of pollution flashover accident so as to prevent the happening of pollution flashover accident. The thesis introduces a set of pollution flashover voltage evaluation system for porcelain insulator which can anticipate the pollution flashover voltage of insulator and prevent the happening of the pollution flashover accident through monitoring the weather conditions such as the temperature and humidity, electric parameters such as the leakage current and circuit operating conditions such as the voltage class and type of insulator and considering their influences comprehensively. According to the set of pollution flashover evaluation system, we had a mass of tests in the thesis to fully verify the accuracy and reliability of this system that satisfy the requirement of electric power department.
Authors: Yu Sheng Quan, Bo Yi, Shai Gen Han, Zi Sen Ning
Abstract: This paper does aging test about zinc oxide varistor and collects the waveform data from the arrester before and after aging, then uses numerical calculation and FFT to analyze the waveform data. Through comparing the changes of characteristic parameters before and after aging such as power loss of varistor, leakage current and every harmonic current, this paper can get the relationship between varistor aging and leakage current, especially the changes of resistive fundamental and harmonic current after aging. Based on analysis and study of aging characteristic parameters of the arresters, it can provide the basis of the judgment for putting forward a new online monitoring method and contributes to the application and development of MOA monitoring technology.
Authors: Takuji Hosoi, Makoto Harada, Yusuke Kagei, Yuu Watanabe, Takayoshi Shimura, Shuhei Mitani, Yuki Nakano, Takashi Nakamura, Heiji Watanabe
Abstract: We propose the use of an aluminum oxynitride (AlON) gate insulator for 4H-SiC MIS devices. Since direct deposition of AlON on 4H-SiC substrate generates a large amount of interface charge due to an interfacial reaction, a thick AlON layer was deposited on underlying thin SiO2 thermally grown in N2O ambient. To reduce the negative fixed charge density in the aluminum oxide (Al2O3) film, we used reactive sputtering of Al in an N2/O2 gas mixture. The fabricated MIS capacitor with AlON/SiO2 stacked gate dielectric shows no flat band voltage shift and negligible capacitance-voltage hysteresis (30 mV), indicating the dielectric is almost free from both fixed charges and electrical defects. Owing to the high dielectric constant of AlON (k=6.9), as compared to single N2O-SiO2 gate insulator, significant gate leakage reduction was achieved by AlON/SiO2 stacked gate dielectrics even at high-temperature, especially in a high electric field condition (>5 MV/cm).
Authors: Jean Baptiste Fonder, Pierre Brosselard, Dominique Tournier, Maxime Berthou, Bertrand Vergne
Abstract: An ultrafast I-V measurement technique has been developed to measure simultaneously C-V and leakage parameters of SiC power devices. After considering the coupled contribution of both static (leakage current) and dynamic (capacitive current) aspects with respect to high dV/dt voltage ramps, a time-based characterization is detailed and validated on SiC Junction Barrier Schottky (JBS) power diodes.
Authors: Takashi Tsuji, T. Tawara, Ryohei Tanuma, Yoshiyuki Yonezawa, Noriyuki Iwamuro, K. Kosaka, H. Yurimoto, S. Kobayashi, Hirofumi Matsuhata, Kenji Fukuda, Hajime Okumura, Kazuo Arai
Abstract: The authors fabricated pn diodes with Al+ implantation in p-type epitaxial layers, and investigated the influence of the implantation dose on reverse leakage currents. Only in the highest dose with the Al concentration of 2x1020cm-3, more than 90% of the devices showed high leakage currents above 10-4A at the maximum electric field of 3MV/cm. In such devices, almost all of the emissive spots corresponded to threading screw dislocations (TSDs) by the analysis of emission microscopy and X-ray topography. These TSDs were defined as killer defects with the estimated density of 500cm-2 in the case of the highest dose. The emissions were supposed to be due to microplasmas, since the spectra of the emissions were different from those of heat radiation. Condensation of Al atoms, nitrogen atoms and DI defects were excluded as the origin of the emissions by secondary ion mass spectrometry and low temperature photoluminescence analyses.
Authors: P. Wimonthanasit, E. Chaidee, P. Jirapong, W. Thipprasert
Abstract: Electrical insulators of the Provincial Electricity Authority (PEA) of medium system are mostly porcelain insulator types that consist of pin type, line post, and pin post insulators. The distribution lines will be polluted by industrial contaminants, salt fog or natural dust. Experience shows that pollution flashover is one of the main natural calamities harming and affecting the voltage stability and reliability of distribution system. This paper compares the test results obtained from the artificial pollution tests according to IEC 60507 in the chamber for tests with standard porcelain insulators consist, pin post, line post and pin type insulators of medium system under same test conditions. The salt fog test results indicate that the pollution flashover performance of pin type insulator is less than to 50 percent of wet power frequency withstand voltage at equivalent salt deposit density (ESDD) = 0.5 mg/cm2 and the leakage current (LC) of pin type insulator increased to 11.4 mA at ESDD = 0.5 mg/cm2 at nominal voltage. In the experiment indicate that AC pollution flashover performance of pin post insulator has better than line post and pin type insulators in the serious pollution area. This data will be useful to be guideline for solving problems and reducing power loss from leakage current on the surface of the insulators as a result of surface dirt and pollution. Moreover, it will be useful to select or design suitable insulators for using in places with salt conditions, high rainfall, high wind speeds and high humidity.
Authors: Takashi Tsuji, Syunsuke Izumi, A. Ueda, Hiroyuki Fujisawa, Katsunori Ueno, Hidekazu Tsuchida, Isaho Kamata, Tamotsu Jikimoto, Kunikaza Izumi
Authors: Nurul Ain Abdul Latiff, Hazlee Azil Illias, Ab Halim Abu Bakar
Abstract: Leakage current is known to be directly related to the degree of degradation of arrester. Leakage current is commonly flow across arrester under non-conducting condition. In this work, a two-dimensional (2D) axial-symmetrical 11kV surge arrester model was developed and used to simulate the leakage current under normal condition. The influence of insulator shed widths, housing materials and sizes of ZnO in an 11kV ZnO surge arrester design on its leakage current was studied using finite element method (FEM) software, which is COMSOL Multiphysics. The simulation results show that leakage current is mostly affected by the sizes of the ZnO and material of the housing. From this work, an understanding on the leakage current behaviors in a ZnO surge arrester can be enhanced. This study may also help in improving the design of surge arresters in reducing leakage current.
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