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学者姓名：张冠军
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Abstract ：
Cable fault location is generally much more difficult if cable defect has not reached the level of serious breakdown. Traditional methods such as time domain reflectometry (TDR) and partial discharge detection cannot solve this problem well due to their low sensitivity. This paper proposes a new non-destructive detection method based on the impedance spectroscopy (IS), which can effectively locate soft faults in the cable. In this paper, a numerical model for cable with distributed parameters is established firstly. Based on this model, cable faults are extracted from the imaginary part of impedance spectrum with Discrete Fourier Transform (DFT). The Chebyshev window is introduced to suppress interference and enhance signal-to-noise ratio, which improves the sensitivity and accuracy of fault location significantly. Experiments and simulations show that this method can well locate multi-segment defects in cables with good accuracy. The window function successfully amplifies the normalized amplitude of faults and improves the positioning accuracy. Compared with other method, this method reduces distortion points effectively. The fault location error is within 0.53%, which has great potential for field application.
Keyword ：
Chebyshev window Circuit faults Coaxial cables Fault location frequency domain reflectometry Impedance non-destructive testing Power cables Reflectometry Soft faults Spectroscopy
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| GB/T 7714 | Mu, Hai-Bao , Zhang, Hao-Tian , Zou, Xing-Yu et al. Sensitivity Improvement in Cable Faults Location by Using Broadband Impedance Spectroscopy With Dolph-Chebyshev Window [J]. | IEEE TRANSACTIONS ON POWER DELIVERY , 2022 , 37 (5) : 3846-3854 . |
| MLA | Mu, Hai-Bao et al. "Sensitivity Improvement in Cable Faults Location by Using Broadband Impedance Spectroscopy With Dolph-Chebyshev Window" . | IEEE TRANSACTIONS ON POWER DELIVERY 37 . 5 (2022) : 3846-3854 . |
| APA | Mu, Hai-Bao , Zhang, Hao-Tian , Zou, Xing-Yu , Zhang, Da-Ning , Lu, Xu , Zhang, Guan-Jun . Sensitivity Improvement in Cable Faults Location by Using Broadband Impedance Spectroscopy With Dolph-Chebyshev Window . | IEEE TRANSACTIONS ON POWER DELIVERY , 2022 , 37 (5) , 3846-3854 . |
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Abstract ：
The experimental investigations of bacteria inactivation of waste water were carried out in a gas-liquid discharge reactor. Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) were selected as the typical Gram-negative and Gram-positive bacteria to study the sterilization efficiency of the device. The experimental results showed that pulsed discharges had a great effect of fast inactivation on microorganisms in waste water. After only 3 minutes of plasma treatment, the sterilization rates of both E. coli and S. aureus could reach to 99.99%. To investigate the sterilization mechanism of plasma, observations of scanning electron microscopy (SEM) and measurements of protein leakage were made. After plasma treatment, structures and morphologies of both two bacteria cells had undergone significant variations. With the increment of the discharge treatment time, protein leakage of the two bacteria kept increasing. The active radicals, high electric field and shock waves may work together to cause the severe damage of bacteria by interacting with cell walls. This may provide technical guide for the further application of microbial inactivation by gas-liquid plasma in waste water. © 2021 IEEE.
Keyword ：
Electric discharges Escherichia coli Liquids Plasma applications Proteins Scanning electron microscopy Shock waves Sterilization (cleaning)
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| GB/T 7714 | Ni, Zhengquan , Li, Yuan , Wen, Jiaye et al. Fast Bacteria Inactivation of Waste Water by Gas-liquid Plasma [C] . 2021 . |
| MLA | Ni, Zhengquan et al. "Fast Bacteria Inactivation of Waste Water by Gas-liquid Plasma" . (2021) . |
| APA | Ni, Zhengquan , Li, Yuan , Wen, Jiaye , Zhang, Guanjun . Fast Bacteria Inactivation of Waste Water by Gas-liquid Plasma . (2021) . |
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Abstract ：
In this work, the influence of varying mixing ratios of O-2 on positive streamer initiation in supercritical (SC) CO2 at different applied voltages was investigated using a 3-D particle model. Zener's model was included in the 3-D particle model to calculate the field ionization rate during streamer formation and propagation. The evolution of positive streamer was classified into three main stages namely inception cloud, primary streamer channels, and successive streamer branching. The effect of O-2 with different mixing ratios (2%, 10%, and 20%) on the morphology, average electron density, electric field distribution, streamer length, and electron energy distribution function (EEDF) for positive streamer in SC-CO2 at four different voltages (12, 12.5, 13, and 13.5 kV) is then investigated. The 2-D cross sections of the initial stage of the streamer and the electric field distribution are presented in detail. At the same applied voltage, the size of inception cloud, average electron density, electric field, and streamer length with the maximum electric field decreased with increasing oxygen concentration in SC-CO2. With increasing applied voltage, the apparent size of inception cloud, primary streamer channels, successive streamer branching, average electron density, electric field, and streamer length increased. The simulation results showed that adding O-2 to SC-CO2 can significantly affect the streamer initiation and propagation.
Keyword ：
3-D field ionization particle model positive streamer initiation supercritical (SC) CO2
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| GB/T 7714 | Abbas, Muhammad Farasat , Sun, Guang Yu , Yuan, Xu Chu et al. The Influence of O-2 on Positive Streamer Initiation in Supercritical CO2 With Field Ionization Using a 3-D Particle Model [J]. | IEEE TRANSACTIONS ON PLASMA SCIENCE , 2021 , 49 (6) : 1786-1793 . |
| MLA | Abbas, Muhammad Farasat et al. "The Influence of O-2 on Positive Streamer Initiation in Supercritical CO2 With Field Ionization Using a 3-D Particle Model" . | IEEE TRANSACTIONS ON PLASMA SCIENCE 49 . 6 (2021) : 1786-1793 . |
| APA | Abbas, Muhammad Farasat , Sun, Guang Yu , Yuan, Xu Chu , Li, Xiao Ran , Zhang, Xing , Sun, An Bang et al. The Influence of O-2 on Positive Streamer Initiation in Supercritical CO2 With Field Ionization Using a 3-D Particle Model . | IEEE TRANSACTIONS ON PLASMA SCIENCE , 2021 , 49 (6) , 1786-1793 . |
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Abstract ：
Secondary electron emission (SEE) of solid materials due to electron bombardment is influenced by numerous properties of materials, where the surface condition plays a critical role in the value of secondary electron yield (SEY). Here, a 3D random microstructure surface model is established to simulate realistic surface morphology and study its effects on SEY by implementing a path tracing algorithm and finite element method. It is found that electron collision frequency on surfaces is strongly affected by local surface geometry parameters, namely the vertical height and the distance between similar features along the horizontal direction of random microstructure surfaces. Manipulating the interaction angle and the inter-barrier collision frequency could quantitively suppress or intensify SEE, allowing for functional design of solid material surfaces under various contexts. In addition, empirical roughness parameters (R-a, R-z) lack certain microscopic information. A method is proposed to estimate secondary electron yield numerically for a given material surface geometry. It provides copious utilities in practical SEE-related applications.
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| GB/T 7714 | Yang, Ning , Song, Baipeng , Yang, Xiong et al. A method to numerically determine the secondary electron yield considering effects of the surface morphology [J]. | JOURNAL OF APPLIED PHYSICS , 2021 , 130 (6) . |
| MLA | Yang, Ning et al. "A method to numerically determine the secondary electron yield considering effects of the surface morphology" . | JOURNAL OF APPLIED PHYSICS 130 . 6 (2021) . |
| APA | Yang, Ning , Song, Baipeng , Yang, Xiong , Zhou, Rundong , Sun, Guangyu , Xue, Jianyi et al. A method to numerically determine the secondary electron yield considering effects of the surface morphology . | JOURNAL OF APPLIED PHYSICS , 2021 , 130 (6) . |
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Abstract ：
The problem that often occurs in the field is the occurrence of soft defects that occur when installing cables due to various factors such as being pinched, punctured, or peeled. Over last year, many methods are based on non-destructive tests such as Line Resonance Analysis (LIRA), Broadband Impedance Spectroscopy (BIS). Time Domain Reflectometry, Joint Time-Frequency Domain Reflectometry is carried out. Although some of these test methods have been able to detect local degradation but to interpret the type of defect is still infancy. This work uses the BIS method with RG 58 CU cable of 33.5 meters total length. The degraded portion is done by using several types, the first is to use mechanical damage by bending beyond the cable's tolerance limit damage, and the second is by connecting the resistance (100 Ohm) or capacitance (10nF) value using the T joint connector. The results are comparing by simulation with ANSYS Electronics Desktop. The results are the type of defect caused by the mechanical press, and the peeled parts have different characteristics. Besides, the IT transform method and IFFT method both of them can detect precisely the degraded portion at 18.5 meters long of 33.5 meters total length of the cable under test. © 2021 IEEE.
Keyword ：
Cables Defects Fits and tolerances Frequency domain analysis Nondestructive examination Presses (machine tools) Reflection Reflectometers Spectroscopy Time domain analysis
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| GB/T 7714 | Siswoyo, Agung , Zhang, Guan-Jun , Suwarno . Broadband Impedance Spectroscopy for Locating and Detecting Various Type of Degraded Portion along with Polymeric Cable [C] . 2021 : 1-7 . |
| MLA | Siswoyo, Agung et al. "Broadband Impedance Spectroscopy for Locating and Detecting Various Type of Degraded Portion along with Polymeric Cable" . (2021) : 1-7 . |
| APA | Siswoyo, Agung , Zhang, Guan-Jun , Suwarno . Broadband Impedance Spectroscopy for Locating and Detecting Various Type of Degraded Portion along with Polymeric Cable . (2021) : 1-7 . |
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Abstract ：
As an emerging technology, low-temperature plasma (LTP) is widely used in medical fields such as sterilization, wound healing, stomatology, and cancer treatment. Great achievements have been made in tumor therapy. In vitro and in vivo studies have shown that LTP has anti-tumor effects, and LTP is selective to tumor cells. Studies in recent years have found that LTP can activate dendritic cells (DC), macrophages, T cells, and other immune cells to achieve anti-tumor effects. This paper reviews the current status of tumor immunotherapy, the application of LTP in antitumor therapy, the activation of antitumor immunity by LTP, the possible mechanism of LTP in antitumor immunity, and meanwhile analyses the prospect of applying LTP in tumor immunotherapy.
Keyword ：
immunotherapy low-temperature plasma tumor
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| GB/T 7714 | Wang, Xiangni , Shi, Xingmin , Zhang, Guanjun . Research Advances and Application Prospect of Low-Temperature Plasma in Tumor Immunotherapy [J]. | APPLIED SCIENCES-BASEL , 2021 , 11 (20) . |
| MLA | Wang, Xiangni et al. "Research Advances and Application Prospect of Low-Temperature Plasma in Tumor Immunotherapy" . | APPLIED SCIENCES-BASEL 11 . 20 (2021) . |
| APA | Wang, Xiangni , Shi, Xingmin , Zhang, Guanjun . Research Advances and Application Prospect of Low-Temperature Plasma in Tumor Immunotherapy . | APPLIED SCIENCES-BASEL , 2021 , 11 (20) . |
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Abstract ：
Power cables in the urban power supply system are laid in cable trenches or directly buried underground, and the insulation is susceptible to corrosion and penetration, causing local insulation aging or abrasion. Early detection of soft faults helps prevent power system faults from occurring. This paper proposes a method that can detect cable multi-point soft faults and distinguish fault types based on Frequency Domain Reflectometry (FDR). Firstly, we establish a numerical calculation model of distributed parameters to analyze the impedance spectroscopy characteristics of different types of defects and the positioning methods and errors. Next, a simulation study was carried out for different characteristics of aging and damage, which means different types of soft faults were successfully distinguished. Then, based on the results of the simulation, experiments are carried out to verify the effectiveness of the positioning algorithm and the feasibility of distinguishing defect types. Simulation and experiment show that the positioning error is within 0.5% and 1% simultaneously. Compared with traditional location methods, the defect location method proposed in this paper can determine the type and severity of the defect while locating multiple defects. The experimental results show that the defect identification method proposed in this paper has great potential for field application. © 2021 IEEE.
Keyword ：
Cables Defects Distributed parameter control systems Electric power systems Fault detection Frequency domain analysis Location Numerical methods Reflection Reflectometers Underground cables Underground corrosion
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| GB/T 7714 | Zhang, Haotian , Mu, Haibao , Zou, Xingyu et al. A Novel Method for Identifying Cable Defect and Improving Location Accuracy Based on Frequency Domain Reflectometry [C] . 2021 . |
| MLA | Zhang, Haotian et al. "A Novel Method for Identifying Cable Defect and Improving Location Accuracy Based on Frequency Domain Reflectometry" . (2021) . |
| APA | Zhang, Haotian , Mu, Haibao , Zou, Xingyu , Zhang, Daning , Zhang, Guanjun , Xie, Cheng . A Novel Method for Identifying Cable Defect and Improving Location Accuracy Based on Frequency Domain Reflectometry . (2021) . |
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Abstract ：
With the extensive application of 10kV overhead insulated lines, grounding accidents caused by insulation degradation or damage seriously affect reliable operation of the distribution network. The insulation status of overhead insulated lines is comprehensive result of complicated operating conditions, such as thermal aging, damp oxidation and transient overvoltage damage. Thus degradation status assessment is of great significance to power supply safety. In this paper, frequency domain spectroscopy (FDS) method is applied to evaluate degradation status of various aging overhead insulated lines. Firstly, accelerated thermal aging samples in 80°C are prepared, and quantization parameters obtained are assessed corresponding to aging statues. As the aging time increases, the loss peaks appearing in the complex permittivity and complex capacitance gradually shifts to low frequencies, and the loss peaks finally decreases. The verification results show that FDS method is an effective and rapid access of degradation status assessment. © 2020 IEEE.
Keyword ：
Complex networks Electric power systems Frequency domain analysis Thermal aging Thermal insulation
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| GB/T 7714 | Meng, Hailei , Wu, Xiaodong , Zhang, Kai et al. Aging evaluation of 10kV overhead cables based on frequency domain spectroscopy [C] . 2020 . |
| MLA | Meng, Hailei et al. "Aging evaluation of 10kV overhead cables based on frequency domain spectroscopy" . (2020) . |
| APA | Meng, Hailei , Wu, Xiaodong , Zhang, Kai , Liu, Haiyong , Mao, Huiqing , Gao, Feng et al. Aging evaluation of 10kV overhead cables based on frequency domain spectroscopy . (2020) . |
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Abstract ：
Corona discharge, an inevitable phenomenon, may lead to insulation degradation, threatening the safe and reliable operation of gas-insulated power equipment. The pulse stage is a complex but usual discharge process in corona discharge. In this paper, we investigate the pulse characteristics of negative corona discharge in a needle-to-plane electrode configuration in SF6/N-2 gas mixtures under DC voltages. With an increase in mean current, a stage transition phenomenon from the Townsend stage through the pulse stage to the breakdown stage is observed. The variation in pulse amplitude and pulse time characteristics at the pulse stage is analyzed. In addition, the effects of gas pressure, gap spacing, and N-2 content on onset voltage and pulse characteristic parameters, including pulse time parameters and the pulse repetition rate, at the pulse stage are presented. The results show that the current pulses mainly exhibit an irregular distribution of small amplitude. The pulse time parameters are not affected by gas pressure, gap spacing, or N-2 content at pressures higher than 0.1 MPa. The pulse repetition rate decreases with an increase in gas pressure and N-2 content but is only weakly affected by gap spacing, ranging from 1 kHz to dozens of kHz.
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| GB/T 7714 | He, Yanliang , Sun, Anbang , Xue, Jianyi et al. Experimental study on pulse characteristics of negative corona discharge in SF6/N-2 gas mixtures under DC voltages [J]. | AIP ADVANCES , 2020 , 10 (5) . |
| MLA | He, Yanliang et al. "Experimental study on pulse characteristics of negative corona discharge in SF6/N-2 gas mixtures under DC voltages" . | AIP ADVANCES 10 . 5 (2020) . |
| APA | He, Yanliang , Sun, Anbang , Xue, Jianyi , Shen, Zhiwei , Zhang, Xing , Zhang, Guanjun . Experimental study on pulse characteristics of negative corona discharge in SF6/N-2 gas mixtures under DC voltages . | AIP ADVANCES , 2020 , 10 (5) . |
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Abstract ：
In order to improve the diagnose ability of insulation defects of gas insulated switchgear (GIS) and improve the detection experience of ultra-high frequency (UHF) method in the field, detailed tests and diagnosis of multiple voids discharge of 550 kV GIS insulation spacer were performed in this paper. Firstly, the abnormal signal of 550 kV GIS insulation spacer, presenting a characteristic of void discharge, was detected on field by the UHF method. After the replacement of the insulation spacer, the tests of withstand voltage, partial discharge, lightning impulse and X-ray detection were employed to investigate the void discharge of insulation spacer. Meanwhile, the UHF and pulse current methods were used to detect the PD signal of the insulation spacer. The discharge characteristics were compared after the lightning impulse. Finally, further diagnostic analyses were carried out by using time difference location statistics and multi-source discharge separation methods. The results show that there are 8 voids in the insulation spacer, which are linearly distributed. The amplitudes of the signals are positively correlated with UHF and pulse current method. With the increment of applied voltage amplitude, the discharge spectrum gradually changes from single void discharge to multiple voids discharge. The partial discharge initial voltage decreases and the extinguishing voltage does not change after the lightning impulse. The UHF signal amplitude and discharge amount will increase under the same voltage after the lightning impulse. The time difference location statistics and multi-source separation indicate the insulation spacer behaves as multiple discharge source characteristics, which is consistent with the X-ray results. The results can provide field experience for GIS UHF detection and diagnosis. © 2020, High Voltage Engineering Editorial Department of CEPRI. All right reserved.
Keyword ：
Electric switchgear Geographic information systems Insulation Lightning Partial discharges Separation Source separation UHF devices X rays
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| GB/T 7714 | Shao, Xianjun , Zhan, Jiangyang , Chang, Dingge et al. Test and Diagnosis of Multiple Voids Discharge for 550 kV GIS Insulation Spacer [J]. | Gaodianya Jishu/High Voltage Engineering , 2020 , 46 (2) : 554-560 . |
| MLA | Shao, Xianjun et al. "Test and Diagnosis of Multiple Voids Discharge for 550 kV GIS Insulation Spacer" . | Gaodianya Jishu/High Voltage Engineering 46 . 2 (2020) : 554-560 . |
| APA | Shao, Xianjun , Zhan, Jiangyang , Chang, Dingge , Zhou, Yangyang , He, Wenlin , Zhang, Guanjun . Test and Diagnosis of Multiple Voids Discharge for 550 kV GIS Insulation Spacer . | Gaodianya Jishu/High Voltage Engineering , 2020 , 46 (2) , 554-560 . |
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