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学者姓名：王小华
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Abstract ：
This paper presents the results of numerical investigation of the current pulses characteristics in SF6/CF4 mixtures for the negative point-plane corona discharge. The pressure and the temperature of gas mixtures are 0.4 MPa and 300 K, respectively. The CF4 content varies from 20% to 80%. The 2D axisymmetric geometry with point-plane electrodes is investigated, and the three drift-diffusion equations are solved to predict the characteristics of the negative corona discharge. In addition, Poisson's equation is coupled with the above three continuity equations to calculate the electric field. In order to calculate the electron impact coefficients, including the Townsend ionization and attachment coefficients, as well as the mobilities and diffusion coefficients for electrons, the two-term Boltzmann equation is solved. The characteristics of three ionic species at five stages of the first current pulse in 60%SF6-40%CF4 and 20%SF6-80%CF4 mixtures are selected to discuss the development mechanism of current pulses. Moreover, the reduced electric field strengths at the corresponding time instants are presented to help understand the discharge process. The current waveform and the total number of three species are compared in all the cases to analyze the effects of the CF4 content on the discharge. The reduced electric field strength is also helpful in understanding the effects of CF4 content. When the CF4 content increases to 80%, the discharge is more intensive and the pulse frequency also increases.
Keyword ：
CF4 mixtures current pulses negative corona discharge SF6
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| GB/T 7714 | Gao, Qingqing , Wang, Xiaohua , Adamiak, Kazimierz et al. The current pulses characteristics of the negative corona discharge in SF6/CF4 mixtures [J]. | PLASMA SCIENCE & TECHNOLOGY , 2023 , 25 (2) . |
| MLA | Gao, Qingqing et al. "The current pulses characteristics of the negative corona discharge in SF6/CF4 mixtures" . | PLASMA SCIENCE & TECHNOLOGY 25 . 2 (2023) . |
| APA | Gao, Qingqing , Wang, Xiaohua , Adamiak, Kazimierz , Yang, Aijun , Liu, Dingxin , Niu, Chunping et al. The current pulses characteristics of the negative corona discharge in SF6/CF4 mixtures . | PLASMA SCIENCE & TECHNOLOGY , 2023 , 25 (2) . |
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Abstract ：
In this article, the magnetic energy harvester (MEH) based on the current transformer is an innovative method to provide a potential solution for the power supply of sensor networks. Due to the current fluctuation and nonlinearity of the core, the harvester may produce insufficient power at low primary currents, while the core saturates at high primary currents. Aiming at resolving this problem, a novel method is proposed to improve the performance of MEH. In this method, a capacitor and two switches are used to store energy and modulate the core saturation. The performed analyses demonstrate that the proposed method enhances the harvested power under different primary current and load conditions. This is especially more pronounced at low primary currents and loads. It is found that for a low primary current of 2 A(rms) at 50 Hz, the harvested power increases by 206%. Moreover, applying this method can also reduce the load voltage by controlling the alternating on-off of the switches, thereby protecting the harvester in case of high primary currents. The theoretical calculation, circuit simulation, and experimental results demonstrate the effectiveness of this method.
Keyword ：
Capacitor harvested power magnetic energy harvester (MEH) magnetic saturation modulation primary current
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| GB/T 7714 | Liu, Zhu , Zhao, Pengbo , Yang, Aijun et al. A Novel Method for Magnetic Energy Harvesting Based on Capacitive Energy Storage and Core Saturation Modulation [J]. | IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS , 2023 , 70 (3) : 2586-2595 . |
| MLA | Liu, Zhu et al. "A Novel Method for Magnetic Energy Harvesting Based on Capacitive Energy Storage and Core Saturation Modulation" . | IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS 70 . 3 (2023) : 2586-2595 . |
| APA | Liu, Zhu , Zhao, Pengbo , Yang, Aijun , Ye, Kai , Zhang, Renjie , Yuan, Huan et al. A Novel Method for Magnetic Energy Harvesting Based on Capacitive Energy Storage and Core Saturation Modulation . | IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS , 2023 , 70 (3) , 2586-2595 . |
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Abstract ：
Semiconductor gas sensors are important candidates with small size, low-power consumption, and low-cost characteristics for gas sensing in the Internet of Things (IoT), but the nonlinear response, unstable baseline, and the variability of the responses toward temperature and humidity fluctuation harm its performance. Here, we proposed a new technique called virtual alternating current (ac) measurements to enable semiconductor gas sensors to achieve high linear response (R-2 > 0.99), stable baseline, and easily calibrated temperature and humidity fluctuation. The most outstanding advantage of our technique is to achieve excellent performance simply by measuring resistance. The universality and feasibility of our technique were verified by a range of commercial and homemade sensing elements and a range of analyte. We also successfully generalized our technique to non-Debye relaxation systems, which further expands the scope of semiconductor gas sensor types available in our technique. We believe that our technique will enable gas sensing nodes built with semiconductor gas sensors in the IoT to achieve markedly superior performance.
Keyword ：
Alternating current (ac) measurements gas sensor the Internet of Things (IoT)
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| GB/T 7714 | Wang, Dawei , Pan, Jianbing , Huang, Xianbo et al. Virtual Alternating Current Measurements Advance Semiconductor Gas Sensors' Performance in the Internet of Things [J]. | IEEE INTERNET OF THINGS JOURNAL , 2022 , 9 (7) : 5502-5510 . |
| MLA | Wang, Dawei et al. "Virtual Alternating Current Measurements Advance Semiconductor Gas Sensors' Performance in the Internet of Things" . | IEEE INTERNET OF THINGS JOURNAL 9 . 7 (2022) : 5502-5510 . |
| APA | Wang, Dawei , Pan, Jianbing , Huang, Xianbo , Chu, Jifeng , Yuan, Huan , Yang, Aijun et al. Virtual Alternating Current Measurements Advance Semiconductor Gas Sensors' Performance in the Internet of Things . | IEEE INTERNET OF THINGS JOURNAL , 2022 , 9 (7) , 5502-5510 . |
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Abstract ：
As a potential alternative to SF gas, C5F10O has excellent insulation performance. The researches on its insulation performance and decomposition mechanism are very significant for promotion and application. In this paper, power frequency breakdown and lightning impulse test were implemented on C5F10O/CO2 gas mixture under a slightly uneven field. It was found that the insulation performance of C5F10O/CO2 gas mixture at 0.7 MPa could be comparable to SF6 at 0.4 MPa. After detecting the discharge products after pulse spark discharge through electron attachment mass spectrometry, it was found that the products mainly came from the decomposition of C5F10O. The addition of CO2 inhibited the formation of C4F10 and C3F4O, and promoted the formation of CF4O and CF4. The yields of C3F6, C4F10, C3F8, CF4O, C4F10 and C2F2 were positively correlated with the content of C5F10O. The densities of C4F10, C3F4O, C3F8O, CF4O, CF4 and C4F10 increased with the number of discharge pulses, which could be as the characteristic gas of the discharge degree. Although many decomposition products were detected, their yields were very low. These results suggest the promising applicability of C5F10O/CO2 gas mixture for replacing SF6.
Keyword ：
C5F10O CO2 gas mixture Discharge products Electron attachment mass spectrometry Insulation performance SF6 alternative gas
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| GB/T 7714 | Wang, Xiaonan , Wang, Xiaohua , Yuan, Huan et al. Study on the Insulation Performance and Decomposition Characteristics of C5F10O/CO2 Gas Mixture [J]. | PLASMA CHEMISTRY AND PLASMA PROCESSING , 2022 , 42 (4) : 957-971 . |
| MLA | Wang, Xiaonan et al. "Study on the Insulation Performance and Decomposition Characteristics of C5F10O/CO2 Gas Mixture" . | PLASMA CHEMISTRY AND PLASMA PROCESSING 42 . 4 (2022) : 957-971 . |
| APA | Wang, Xiaonan , Wang, Xiaohua , Yuan, Huan , Yang, Aijun , Liu, Dingxin , Gao, Qingqing et al. Study on the Insulation Performance and Decomposition Characteristics of C5F10O/CO2 Gas Mixture . | PLASMA CHEMISTRY AND PLASMA PROCESSING , 2022 , 42 (4) , 957-971 . |
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Abstract ：
Overcharging may occur due to the inconsistency of lithium-ion batteries (LIBs), which is likely to trigger battery failure or thermal runaway (TR). Herein, the aging mechanism and TR behavior of aged LiFePO4 batteries induced by different degrees of slight overcharge cycling are studied. First, the capacity degradation and aging mechanisms are studied qualitatively and quantitatively by conducting in-situ experiments. The results indicate that the high cut-off voltage (4.5 V) accelerates capacity fading, which is dominated by loss of lithium. However, capacity retention is benefited if the overcharge voltage is properly increased (4 and 4.2 V). Then, the TR behavior of cells is tested using the extended volume accelerating rate calorimeter (EV-ARC). The results indicate that the thermal stability of aged cells worsens because the internal short circuit is more likely to occur due to lithium plating on the anode experiencing overcharge cycling. Finally, the intrinsic interaction between the aging mechanism and TR features of slightly overcharged LIBs is revealed. Meanwhile, we also provide valuable information regarding the reusability of LIBs undergoing overcharge cycling. Therefore, this study is useful for battery safety design and early warning of TR.
Keyword ：
Aging Lithium-ion battery Slight overcharge Thermal runaway
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| GB/T 7714 | Yang, Mengjie , Ye, Yijun , Yang, Aijun et al. Comparative study on aging and thermal runaway of commercial LiFePO4/ graphite battery undergoing slight overcharge cycling [J]. | JOURNAL OF ENERGY STORAGE , 2022 , 50 . |
| MLA | Yang, Mengjie et al. "Comparative study on aging and thermal runaway of commercial LiFePO4/ graphite battery undergoing slight overcharge cycling" . | JOURNAL OF ENERGY STORAGE 50 (2022) . |
| APA | Yang, Mengjie , Ye, Yijun , Yang, Aijun , Jiang, Zhiyuan , Wang, Xiaohua , Yuan, Huan et al. Comparative study on aging and thermal runaway of commercial LiFePO4/ graphite battery undergoing slight overcharge cycling . | JOURNAL OF ENERGY STORAGE , 2022 , 50 . |
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Abstract ：
The detection of copper particles in transformer oil based on laser-induced breakdown spectroscopy (LIBS) technology has been preliminarily studied, but its limit of detection (LOD) needs to be further strengthened. Therefore, spark-discharge assistant method was used to solve the problem, and its enhancement mechanism has been studied in the research. The study of the correlation between spark-discharge-assisted LIBS (SD-LIBS) spectral intensity and Cu concentration shows that spark discharge has a significant increase in plasma size and spectral intensity; for Cu atomic lines at 324.75 and 327.39 nm, the determination coefficient R-2 between their internal standard correction intensity and Cu concentration is promoted to 0.996 and 0.997, respectively; spark-discharge assistant method improves the LOD of LIBS from 0.775 to 0.112 mu g/g. Due to the great improvement in detection performance, the application prospect of LIBS as fine particles detection method in transformer oil has become practical.
Keyword ：
Copper particle enhancement laser-induced breakdown spectroscopy (LIBS) spark discharge
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| GB/T 7714 | Ye, Zhe , Ke, Wei , Wang, Wanting et al. Enhancement by Spark Discharge in LIBS Detection of Copper Particle Contamination in Oil-Immersed Transformer [J]. | IEEE TRANSACTIONS ON DIELECTRICS AND ELECTRICAL INSULATION , 2022 , 29 (5) : 2034-2041 . |
| MLA | Ye, Zhe et al. "Enhancement by Spark Discharge in LIBS Detection of Copper Particle Contamination in Oil-Immersed Transformer" . | IEEE TRANSACTIONS ON DIELECTRICS AND ELECTRICAL INSULATION 29 . 5 (2022) : 2034-2041 . |
| APA | Ye, Zhe , Ke, Wei , Wang, Wanting , Yuan, Huan , Wang, Xiaonan , Wang, Xiaohua et al. Enhancement by Spark Discharge in LIBS Detection of Copper Particle Contamination in Oil-Immersed Transformer . | IEEE TRANSACTIONS ON DIELECTRICS AND ELECTRICAL INSULATION , 2022 , 29 (5) , 2034-2041 . |
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Abstract ：
High-impedance faults (HIFs) pose the greatest challenge for distribution system protection, especially for microgrids and distribution networks with distributed generators (DGs) that have flexible operation modes. This paper analyzes the faulty features of HIFs and proposes a HIF detection method that uses empirical wavelet transform (EWT) and differential faulty energy. The proposed method is as follows. First, the various time-frequency components are obtained by utilizing the EWT to decompose the differential faulty energy and adaptively select the feature component with the largest permutation entropy. Second, the permutation variance index is constructed based on the sample point number and feature component energy, and then it is employed to detect HIFs. Finally, low voltage microgrid simulation tests, medium voltage distribution system integrated by DG simulation tests, and field tests show that the proposed method can correctly distinguish HIFs from normal disturbances, including operation mode switches, load switches, capacitor switches, and DG switches. The advantages of the proposed method are also elaborated in detail, from signal preprocessing and feature extraction.
Keyword ：
differential faulty energy empirical wavelet transform Feature extraction Grounding High impedance fault Microgrids permutation entropy permutation variance Time-frequency analysis Transforms Voltage Wavelet transforms
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| GB/T 7714 | Gao, Jie , Wang, Xiaohua , Wang, Xiaowei et al. A High-Impedance Fault Detection Method for Distribution Systems Based on Empirical Wavelet Transform and Differential Faulty Energy [J]. | IEEE TRANSACTIONS ON SMART GRID , 2022 , 13 (2) : 900-912 . |
| MLA | Gao, Jie et al. "A High-Impedance Fault Detection Method for Distribution Systems Based on Empirical Wavelet Transform and Differential Faulty Energy" . | IEEE TRANSACTIONS ON SMART GRID 13 . 2 (2022) : 900-912 . |
| APA | Gao, Jie , Wang, Xiaohua , Wang, Xiaowei , Yang, Aijun , Yuan, Huan , Wei, Xiangxiang . A High-Impedance Fault Detection Method for Distribution Systems Based on Empirical Wavelet Transform and Differential Faulty Energy . | IEEE TRANSACTIONS ON SMART GRID , 2022 , 13 (2) , 900-912 . |
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Abstract ：
Modular hybrid dc circuit breakers (DCCBs) have been widely employed to protect multiterminal high-voltage dc (MT-HVdc) grids. However, breaker failures still pose a challenge to the protection of MT-HVdc grids, especially for a single module failure of breakers. To this end, a breaker failure detection method based on nonlinear parameter estimation is presented. This proposed method consists of three parts. The first is a signal preprocessing method that eliminates the effect of the RC circuit of the hybrid DCCB. The second is an offline optimal parameter acquisition method that has an improved numerical model of the metal-oxide varistor (MOV) and combines the Levenberg-Marquardt (LM) algorithm with the particle swarm optimization (PSO) algorithm. The third is an online breaker voltage error calculation that estimates the breaker voltage based on the improved numerical MOV model to detect the partial failure of the modular hybrid DCCB. The performance of the proposed algorithm is evaluated by both power system computer aided design (PSCAD)/electro-magnetic transient design and control (EMTDC) tests and field tests. The study results prove the effectiveness of the proposed method for the partial failure of the modular hybrid DCCB considering different faulty conditions and the aging of MOVs.
Keyword ：
Breaker failure detection Circuit breakers Circuit faults Fault currents Insulated gate bipolar transistors Integrated circuit modeling metal-oxide varistor (MOV) modular hybrid dc circuit breaker (DCCB) multiterminal high-voltage dc (MT-HVdc) grids Numerical models Switching circuits voltage error calculation
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| GB/T 7714 | Gao, Jie , Yuan, Huan , Yang, Aijun et al. A Breaker Failure Detection Method Based on Nonlinear Parameter Estimation for Modular Hybrid DC Circuit Breakers [J]. | IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT , 2022 , 71 . |
| MLA | Gao, Jie et al. "A Breaker Failure Detection Method Based on Nonlinear Parameter Estimation for Modular Hybrid DC Circuit Breakers" . | IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT 71 (2022) . |
| APA | Gao, Jie , Yuan, Huan , Yang, Aijun , Rong, Mingzhe , Wang, Xiaohua . A Breaker Failure Detection Method Based on Nonlinear Parameter Estimation for Modular Hybrid DC Circuit Breakers . | IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT , 2022 , 71 . |
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Abstract ：
This article proposes a lightweight network called multiscale convolutional neural network with attention (MCNA), which combines a multiscale deep convolutional network with a self-attention mechanism. MCNA identifies ambient gases through signals of semiconductor gas sensor arrays, despite poor selectivity and drift problems. Notably, MCNA extracts temporal features of each signal and relevance among different signals more effectively than deep convolutional networks. MCNA requires much fewer parameters and computation costs than previous deep learning networks, but it still achieves the same high gas identification accuracy; this is crucial for gas sensing embedded systems. When the operating conditions of the gas sensor array change, it also exhibits better generalization ability and identification accuracy. We also discuss the effects of different MCNA architecture parameters and compare MCNA and other baseline approaches.
Keyword ：
Convolution Convolutional neural network (CNN) Feature extraction Gas detectors gas identification lightweight network Machine learning multiscale learning strategy self-attention mechanism Sensor arrays Temperature sensors Transformers
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| GB/T 7714 | Pan, Jianbin , Yang, Aijun , Wang, Dawei et al. Lightweight Neural Network for Gas Identification Based on Semiconductor Sensor [J]. | IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT , 2022 , 71 . |
| MLA | Pan, Jianbin et al. "Lightweight Neural Network for Gas Identification Based on Semiconductor Sensor" . | IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT 71 (2022) . |
| APA | Pan, Jianbin , Yang, Aijun , Wang, Dawei , Chu, Jifeng , Lei, Fangfei , Wang, Xiaohua et al. Lightweight Neural Network for Gas Identification Based on Semiconductor Sensor . | IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT , 2022 , 71 . |
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Abstract ：
The power transmission line on-line monitoring system is of great significance for ensuring the safe operation of the power system. In this paper, a monitoring system based on standardized A and B interface grid protocols, image processing and state tracking is designed. The system is divided into front-end and back-end system. The front-end system monitors the video data and transmits it to the data platform through the A interface protocol. By the B-interface protocol, data is transmitted to the back-end system. The back-end system performs data processing and fault state tracking. At first, this paper describes the hardware and software architecture, and then explains the implementation of the functions. Finally, compared to traditional equipment, the design concept in this paper can achieve on-line monitoring better. © 2021, Beijing Oriental Sun Cult. Comm. CO Ltd.
Keyword ：
Data handling Electric lines Electric power transmission Image processing Interface states Monitoring Power transmission Transmissions Voltage measurement
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| GB/T 7714 | Wang, Lujin , Yuan, Huan , Wang, Xiaohua et al. Design of a Power Transmission Line On-line Monitoring System Based on A/B Interface Grid Protocols [C] . 2021 : 89-97 . |
| MLA | Wang, Lujin et al. "Design of a Power Transmission Line On-line Monitoring System Based on A/B Interface Grid Protocols" . (2021) : 89-97 . |
| APA | Wang, Lujin , Yuan, Huan , Wang, Xiaohua , Guo, Yue , Yang, Aijun . Design of a Power Transmission Line On-line Monitoring System Based on A/B Interface Grid Protocols . (2021) : 89-97 . |
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