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space charge Characteristics of Oil-paper Insulation in the Electro-thermal Aging Process

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CSEE Journal of Power and Energy Systems 2016年第2期2卷 40-46页

作者： Yuanxiang Zhou Chao Dai Meng Huang Department of Electrical Engineering Tsinghua UniversityBeijing 10084China Electrical Engineering Department Beijing Jiaotong UniversityBeijing 100044China

High electric field and temperatures can result in electrical property degradation of oil-paper insulation and accelerate its aging *** paper describes the regulation of space charge in the process of electro-thermal *** field distortion and differences in characteristic parameters during electro-thermal aging are analyzed,along with the effects of electro-thermal aging on space charge from the perspective of trap *** temperature and an electric field are used to accelerate the aging of oil-paper,and space charge characteristics are measured using the pulsed electro-acoustic(PEA)method throughout the electro-thermal *** on results obtained,it can be concluded that homo-charge injection occurs at the anode and the type of the charge injection at the cathode varies throughout the electro-thermal aging;the decrease of permittivity during aging allows for space charge injection to take place;growth of trap depth makes the space charge accumulate in the middle of the sample;and space charge accumulation after electro-thermal aging results in inner electric field distortion,which leads to large current and decreased breakdown in voltages.

关键词： Electric field distortion electro-thermal aging homogeneous charge oil-paper insulation pulsed electro-acoustic(PEA)method space charge

Measurement of the secular motion frequency and the space charge density in the linear ion trap

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Chinese Physics B 2010年第11期19卷 294-300页

作者：周飞谢艺徐酉阳黄学人冯芒 State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics Wuhan Institute of Physics and MathematicsChinese Academy of Sciences Graduate School of the Chinese Academy of Sciences

This paper reports that a cloud of laser-cooled ^40Ca^＋ is successfully trapped and manipulated in the home-built linear ion trap constructed for quantum information processing （QIP）. The frequency of the secular motion and the space charge density of the ion cloud are measured, which help knowing the characteristic of the trapping potential and are the prerequisite of QIP with the trapped ions.

关键词： trapped ions secular motion frequency space charge

Influence of sub-bandgap illumination on space charge distribution in CdZnTe detector

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Chinese Physics B 2021年第3期30卷 378-385页

作者： Rongrong Guo Jinhai Lin Lili Liu Shiwei Li Chen Wang Feibin Xiong Haijun Lin Fujian Provincial Key Laboratory of Optoelectronic Technology and Devices Xiamen University of TechnologyXiamen 361024China

The space charge accumulation in CdZnTe crystals seriously affects the performance of high-flux pulse *** influence of sub-bandgap illumination on the space charge distribution and device performance in CdZnTe crystals were studied theoretically by Silvaco TCAD software *** sub-bandgap illumination with a wavelength of 890 nm and intensity of 8×10−8 W/cm2 were used in the simulation to explore the space charge distribution and internal electric field distribution in CdZnTe *** simulation results show that the deep level occupation faction is manipulated by the sub-bandgap illumination,thus space charge concentration can be reduced under the bias voltage of 500 V.A flat electric field distribution is obtained,which significantly improves the charge collection efficiency of the CdZnTe ***,premised on the high resistivity of CdZnTe crystal,the space charge concentration in the crystal can be further reduced with the wavelength of 850 nm and intensity of 1×10−7 W/cm2 *** electric field distribution is flatter and the carrier collection efficiency of the device can be improved more effectively.

关键词： CdZnTe detector sub-bandgap illumination space charge charge collection efficiency

Effect of space charge on the Propagation Path of Air Gap Discharge

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Plasma Science and Technology 2011年第6期13卷 714-718页

作者：郝丽霞王伟詹花茂韩筱慧邓丽红 Beijing Area Major Laboratory of High Voltage and EMC State Key Laboratory of' Alternate Electrical Power System with Renewable Energy SourcesNorth China Electric Power University

The existence of space charge may be addressed as one of the reasons that could cause shielding failure of transmission lines. In order to study the effect of space charge on discharge propagation path, a new experimental system, including mainly DC high voltage generator, impulse voltage generator as well as rod-plane electrode, has been established. The space charge was generated around the rod by means of pre-applying DC high voltage, and the air gap dis- charge experiments were conducted with and without pre-applying DC high voltage, respectively. Meanwhile, high speed cameras worked simultaneously from the front and lateral side to record the discharge propagation path so as to obtain the curvature. After statistical analysis, it is shown that the curvature increases in the middle and lower portions of the propagation path when the effect of space charge is taken into account.

关键词： curvature discharge propagation path high speed cameras space charge

Research on the feature extraction of DC space charge behavior of oil-paper insulation

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Science China(Technological Sciences) 2011年第5期54卷 1315-1324页

作者： TANG Chao LIAO RuiJin CHEN George YANG LiJun College of Engineering and Technology Southwest University Chongqing 400715 China The State Key Laboratory of Power Transmission Equipment & System Security and New Technology Chongqing University Chongqing 400044 China School of Electronics and Computer Science University of Southampton Southampton SO17 3B J UK

As the ultra high DC voltage grid comes into an important stage in the ‘Twelfth Five-year Plan’ of China, the requirement on the operation safety of power equipment needs to be improved. Oil-paper insulation plays a significant role as the main insulation material of many key power equipments. The space charge behaviors of oil-paper insulation not only affect the dielectric strength, but also relate to the stability and security of power transmission facilities. Until now, the research on the space charge behaviors of oil-paper insulation remains on the stage of objective description and phenomenon explanation, thus it is very urgent to make some feature extractions on the test results in order to further investigate the DC space charge behaviors of oil-paper insulation. In this paper, based on the large numbers of test data in the first stage, data mining and feature extractions were performed on the DC space charge behavior of oil-paper insulation. The variation laws of some key characteristic parameters obtained in different experiment conditions such as the total charge injection amount, apparent charge mobility, and trap energy distribution were analyzed. In addition, the distribution of trapping level inside oil-paper was calculated by using the PEA test results based on the mechanism of the isothermal decay current, which realized the approximate calculation of trap depth by charge decay characteristics. What’s more, the exponential injection and decay equations of DC space charge changing with time were acquired for the first time, and the physical meanings of related parameters were defined. This has laid a foundation for the prediction and simulation of space charge in the oil-paper insulation.

关键词： oil-paper insulation space charge DC feature extraction

Relationship between space charge and nonlinear characteristics of ZnO varistor

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Science China(Technological Sciences) 2011年第7期54卷 1771-1778页

作者： WANG Qian TU YouPing DING LiJian JU ZeLi Beijing Key Laboratory of High Voltage & EMC North China Electric Power University Beijing 102206 China

In order to reveal the conduction mechanism of ZnO varistor, the pulsed electroacoustic (PEA) measurement is employed to investigate the space charge distribution characteristics of ZnO varistors under different current densities in this paper. Experimental results show that the relationship between the space charge and the current density is consistent with the voltage-current characteristics, and can reflect the nonlinear characteristics of ZnO varistor. The space charge increases linearly with the increase of the electric field strength and the current density in the small current region, this reflects the decrease of the surface states of the grain boundary and changes of the Schottky barrier. There exists a transition region between the small current and middle current regions, where the current is composed of the current by the emission of thermally activated electrons and the tunneling current. In the middle current region, the space charge will decrease as the current increases, and will disappear with the depletion layer decreasing to zero.

关键词： ZnO varistors pulsed electroacoustic (PEA) measurement space charge double Schottky barrier

Influence of Oil Paper Composition on the space charge Characteristics

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CSEE Journal of Power and Energy Systems 2015年第3期1卷 10-15页

作者： C.H.Chen Kai Wu Rui Su Shengtao Li Department of Electrical Engineering of Xi’an Jiaotong University Xi’an 710049China State Key Laboratory of Electrical Insulation and Power Equipment Xi’an Jiaotong UniversityXi’an 710049China

space charge inside oil paper insulation can severely distort the electric field distribution and lead to degradation of electrical performance of materials.A vast number of articles about the space charge characteristics of oil paper insulation under different conditions has been published;however,few report the influence of oil paper *** this paper,a comparison of the space charge distribution as well as the electrical conductivity of four combinations of transformer oil(Kunlun#25 and Nynas oil)and paper(type I from XD factory,type II imported from France)is carried *** results show that the combination of type II paper and Kunlun oil performs well with minimal charge accumulation inside the *** understand the phenomenon,results of space charge measurements and electrical conductivity are associated.A microscopic inspection of two types of paper is conducted to acquire the surface condition of the *** relationship between space charge injection quantity and surface condition of the papers is *** is observed that a relatively higher conductivity of oil as well as a smooth,dense surface of paper can suppress space charge in oil paper insulation.

关键词： Electric conduction oil paper composition microstructure space charge

Numerical Analysis of space charge Characteristics in Low-density Polyethylene Nanocomposite under External DC Electric Field

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Numerical Analysis of Space Charge Characteristics in Low-de...

Research progress on space charge characteristics in polymeric insulation

中国物理学会第十八届全国静电学术会议

作者： ZHOU Yuanxiang ZHANG Ling SHA Yanchao TIAN Jihuan State Key Laboratory of Control and Simulation of Power System and Generation Equipments Tsinghua University ABB (China) Limited Universal

In this work, we are interested in space charge dynamics characteristics in the low-density polyethylene（LDPE） nanocomposite mixed with some mass fraction of inorganic nanofillers. Different with all previous qualitatively theoretical works, numerical simulation based on the bipolar charge transport model was performed to systematically investigate the influence of trap depth, trap concentration, and injection barrier height on the space charge and electric field distributions under DC external electric field of 100 k V/mm. Our simulation results showed that increasing the trap depth would severely distort the electric field distribution at the balanced status with the highest and lowest electric field of 119 k V/mm and 47 k V/mm, respectively. Due to the introduction of nanofillers, more deep traps were created and blocked the space charge movement, capturing most of space charge in the vicinity of the electrode and largely declining the local electric field further. In addition, our theoretical analysis also showed both the high permittivity and low local electric field contributed to the increase of injection barrier height. Once the injection barrier height surpassed 1.25 e V, there was almost no charge that could overcome the injection barrier. At last, a mechanism of space charge suppression in the LDPE nanocomposite was presented.

关键词： LDPE nanocomposite space charge bipolar charge transport model trap depth Schottkyinjection barrier height

来源： cnki会议评论

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Journal of Advanced Dielectrics 2016年第1期6卷 5-17页

作者： Yibo Zhang Thomas Christen Xing Meng Jiansheng Chen Jens Rocks ABB(China)Limited Corporate ResearchUBP B6L110 Jiuxianqiao Lu Chaoyang DistrictBeijing 100015P.R.China ABB Schweiz AG Corporate ResearchSegelhofstrasse 1KCH-5405 Baden 5 DattwilSwitzerland

Due to their excellent electrical insulation properties and processability,polymer materials are used in many electrical *** is widely believed that space charge plays an important role for the electric field distribution,conduction,ageing,and electric breakdown of polymeric *** paper reviews measurements and characteristics of space charge behavior which mainly determined by the pulsed electro-acoustic(PEA)measurement *** interests are the effects of the applied voltage,the electrodes,temperature,humidity,microstructure,additives,and filler materials on accumulation,distribution,transport,and the decay of space charge in polymeric *** review paper is to provide an overview on various space charge effects under different conditions,and also to summarize the information for polymeric materials with suppressed space charge and improved electrical behavior.

关键词： Polymeric insulation space charge PEA nanocomposite