Search

Your search keyword '"Qian, Guochao"' showing total 99 results
Start Over Author "Qian, Guochao"
99 results on '"Qian, Guochao"'

1. Harmonic Voltage Effect on Partial Discharge Characteristics of Oil-Paper Insulation Under Non-uniform Electric Field

Author

Dai, Weiju, Hong, Zhihu, Wang, Shan, Qian, Guochao, Wu, Jie, Xia, Ruochun, Angrisani, Leopoldo, Series Editor, Arteaga, Marco, Series Editor, Chakraborty, Samarjit, Series Editor, Chen, Jiming, Series Editor, Chen, Shanben, Series Editor, Chen, Tan Kay, Series Editor, Dillmann, Rüdiger, Series Editor, Duan, Haibin, Series Editor, Ferrari, Gianluigi, Series Editor, Ferre, Manuel, Series Editor, Jabbari, Faryar, Series Editor, Jia, Limin, Series Editor, Kacprzyk, Janusz, Series Editor, Khamis, Alaa, Series Editor, Kroeger, Torsten, Series Editor, Li, Yong, Series Editor, Liang, Qilian, Series Editor, Martín, Ferran, Series Editor, Ming, Tan Cher, Series Editor, Minker, Wolfgang, Series Editor, Misra, Pradeep, Series Editor, Mukhopadhyay, Subhas, Series Editor, Ning, Cun-Zheng, Series Editor, Nishida, Toyoaki, Series Editor, Oneto, Luca, Series Editor, Panigrahi, Bijaya Ketan, Series Editor, Pascucci, Federica, Series Editor, Qin, Yong, Series Editor, Seng, Gan Woon, Series Editor, Speidel, Joachim, Series Editor, Veiga, Germano, Series Editor, Wu, Haitao, Series Editor, Zamboni, Walter, Series Editor, Tan, Kay Chen, Series Editor, Yang, Qingxin, editor, Li, Zewen, editor, and Luo, An, editor

Published
2024
Full Text
View/download PDF

3. The Adsorption Characteristics of HfS2 for Air Partial Discharge Component CO Based on the First Principle

Author

Qian, Guochao, Hu, Jin, Wang, Shan, Dai, Weiju, Hou, Wenjun, Zhou, Qu, Angrisani, Leopoldo, Series Editor, Arteaga, Marco, Series Editor, Panigrahi, Bijaya Ketan, Series Editor, Chakraborty, Samarjit, Series Editor, Chen, Jiming, Series Editor, Chen, Shanben, Series Editor, Chen, Tan Kay, Series Editor, Dillmann, Rüdiger, Series Editor, Duan, Haibin, Series Editor, Ferrari, Gianluigi, Series Editor, Ferre, Manuel, Series Editor, Hirche, Sandra, Series Editor, Jabbari, Faryar, Series Editor, Jia, Limin, Series Editor, Kacprzyk, Janusz, Series Editor, Khamis, Alaa, Series Editor, Kroeger, Torsten, Series Editor, Li, Yong, Series Editor, Liang, Qilian, Series Editor, Martín, Ferran, Series Editor, Ming, Tan Cher, Series Editor, Minker, Wolfgang, Series Editor, Misra, Pradeep, Series Editor, Möller, Sebastian, Series Editor, Mukhopadhyay, Subhas, Series Editor, Ning, Cun-Zheng, Series Editor, Nishida, Toyoaki, Series Editor, Oneto, Luca, Series Editor, Pascucci, Federica, Series Editor, Qin, Yong, Series Editor, Seng, Gan Woon, Series Editor, Speidel, Joachim, Series Editor, Veiga, Germano, Series Editor, Wu, Haitao, Series Editor, Zamboni, Walter, Series Editor, Zhang, Junjie James, Series Editor, Liang, Xidong, editor, Li, Yaohua, editor, He, Jinghan, editor, and Yang, Qingxin, editor

Published
2022
Full Text
View/download PDF

9. Optimization and identification technology of hyperspectral spectral features of insulator pollution levels

Author

SHEN Long, QIAN Guochao, PENG Zhaoyu, LI Qianhui, YANG Kun, and MA Yutang

Subjects
hyperspectral technology, insulator pollution level, wavelet packet energy spectrum, background segmentation, support vector machine (svm), principal component analysis (pca), Applications of electric power, TK4001-4102
Abstract

To solve the problem of traditional pollution detection methods on the prevention and control of pollution flashover of transmission line insulators,the non-contact and high-resolution hyperspectral technology is used to study the on-line pollution detection technology. At the same time,an insulator pollution level identification technology based on wavelet packet energy spectrum feature optimization is proposed to effectively extract the spectral features reflecting the pollution degree and weaken the influence of redundancy and interference information. Firstly,the spectral images of insulator samples with different pollution levels are segmented to extract the spectral mean curve of pixels in uniform pollution area. Secondly,the difference of light intensity uniformity and environmental noise of different images are preprocessed,and the differentiability among different pollution levels is improved by logarithmic transformation. Thirdly,the feature extraction of wavelet packet energy spectrum is performed on the preprocessed spectral lines. Finally,a pollution level recognition model based on the proposed features and support vector machines (SVM) is established. The experimental results show that the SVM pollution level recognition model based on wavelet energy spectrum features achieves 99.8%,and it has higher recognition accuracy than full band data or principal component analysis (PCA) feature data does.

Published
2022
Full Text
View/download PDF

11. Insulator and Burst Fault Detection Using an Improved Yolov3 Algorithm

Author

Zhou Fangrong, Pan Hao, Qian Guochao, Ma Yutang, Wen Gang, Xu Chao, Kong Peng, Xie Guobo, and Zheng Xiaofeng

Subjects
Article Subject, Control and Systems Engineering, Electrical and Electronic Engineering, Instrumentation
Abstract

Insulators play an important role in the operation of outdoor high-voltage transmission lines. However, insulators are installed in outdoor environments for long periods and thus failures are inevitable. It is necessary to conduct timely insulator inspection and maintenance. In this paper, an improved Yolov3 target detection network (Yolov3-CK) is proposed in order to achieve higher detection accuracy and speed. First, Yolov3-CK uses the CIOU loss function instead of the mean square error loss function from Yolov3. Second, the Yolov3-CK model uses cluster analysis of the priori box via the k -means++ algorithm to obtain a priori box size that is more suitable for the detection of insulators and their burst faults. Finally, we use a dataset obtained by performing data enhancement on the China power line insulator dataset to train and test the data-enhanced Yolov3-CK model. The mean precision of Yolov3-CK reaches 91.67% with 47.9 frames processed per second. Yolov3-CK provides better detection accuracy and a higher processing rate than Faster RCNN, SSD, and Yolov3. Therefore, the Yolov3-CK model is more suitable for the detection of insulators and their burst faults.

Published
2022

12. Adsorption performance and gas sensing of the Ru atomic catalyst on GaN sheets to transformer oil dissolved gases.

Author

Qian, Guochao, Hu, Jin, Dai, Weiju, Zhao, Hanwu, and Yuan, Yao

Subjects
*INSULATING oils, *RUTHENIUM catalysts, *GAS absorption & adsorption, *GALLIUM nitride
Abstract

The Ru atomic catalyst-doped GaN (Ru-GaN) model was established by density functional theory (DFT), and the adsorption models of transformer oil dissolved gas (CO, H2, CH4, C2H2, C2H4 and C2H6) by a Ru-GaN monolayer were optimised. From the adsorption energy, differential charge density, electron state density, molecular orbital and desorption properties, the modification mechanism of Ru-GaN and the gas-sensitive response mechanism of Ru-GaN to CO, H2, CH4, C2H2, C2H4 and C2H6 were systematically studied. The introduction of metal Ru increases the defect state of GaN to provide the active site for the adsorption of gas molecules and reduces the adsorption barrier of GaN to gas molecules. The results show that Ru metal-doped GaN can adsorb CO, C2H2 and C2H4 by chemisorption, with Eads of −2.068 eV, −2.422 eV and −1.877 eV and Qt of −0.1696 e, −0.0671 e, −0.1222 e. In addition, charge redistribution leads to changes in the density of states, molecular orbitals and the conductivity of CO, C2H2 and C2H4 adsorption systems, indicating excellent gas sensitivity to the three gases. The desorption time further verified that Ru-GaN is an ideal CO and C2H2 gas scavenger and a recyclable material for C2H4 gas sensors. [ABSTRACT FROM AUTHOR]

Published
2023
Full Text
View/download PDF

27. Research on Power Load Forecasting Using Deep Neural Network and Wavelet Transform

Author

Tan, Xiangyu, Ao, Gang, Qian, Guochao, Zhou, Fangrong, Li, Wenyun, and Liu, Chuanbin

Abstract

In today's rapid economic development, industrial and civil electricity consumption is growing year by year, and how to guarantee stability of power system operation has become the focus of attention of the power sector in each country. Power load forecasting has been closely associated with the modernization of power system management and is a vital guarantee for the safe and stable operation and economic efficiency of the power system. In this article, the authors propose a recurrent neural network (RNN) decision fusion forecasting framework based on the wavelet transform to address the power load forecasting problem. The framework firstly performs the wavelet transform on the power load data and uses Daubechies wavelets to extract the high-frequency and low-frequency parts of the data; then the data with different frequencies are combined with the original data and fed into the RNN model separately, and the decision fusion is performed in the output layer; finally, the prediction results are obtained by superposition of two RNN networks. The results showed that the error of the predicted data in the last nine years decreased by 50%, compared with the traditional method of feeding the data into the RNN model for training, which provides a new idea for future power load forecasting.

Published
2023
Full Text
View/download PDF

32. Novel Gas-Sensitive Material for Monitoring the Status of SF 6 Gas-Insulated Switches: Gese Monolayer.

Author

Qian, Guochao, Hu, Xiqian, Chen, Weigen, and Zhou, Qu

Subjects
DENSITY of states, ENERGY bands, GAS detectors, DESORPTION, THERMAL desorption
Abstract

Detecting the decomposition components of SF6 insulating gas is recognized as an effective means to monitor the operating status of the SF6 insulating switch. In this paper, the adsorption characteristics of a new two-dimensional material GeSe for five SF6 decomposition gases (SO2, SOF2, SO2F2, H2S and HF) are reported by first-principles simulation. Through the analysis of the change of energy band structure, density of states distribution, and gas desorption time, it is found that GeSe has the potential as a gas-sensitive material for the selective detection of SO2F2, and the computational work in this paper provides theoretical guidance for the development of new gas-sensitive sensors applied in monitoring SF6 insulated switches. [ABSTRACT FROM AUTHOR]

Published
2022
Full Text
View/download PDF

33. Development and test of distributed current monitoring device for dry type air core reactor

Author

Cui Zhigang, Hao Changjin, Liu Yi, Qian Guochao, Ou Yangyong, and Yang Chao

Subjects
010302 applied physics, ComputingMethodologies_SIMULATIONANDMODELING, business.industry, Circuit design, Nuclear engineering, Electromagnetic compatibility, ComputerApplications_COMPUTERSINOTHERSYSTEMS, Inductor, 01 natural sciences, Temperature measurement, 0103 physical sciences, Air core, Environmental science, Wireless, Current sensor, Current (fluid), business
Abstract

Dry type air core reactor is often operated outdoors, and its insulation performance is affected by climate, insulation aging, voltage fluctuation and other factors, which makes it encounter various problems in operation. The results show that the insulation state of the reactor can be evaluated by measuring the distribution current change of the reactor. In this paper, a wireless distributed current sensor is developed for the distributed current measurement of dry type air core reactor. The circuit design, protection structure design and electromagnetic compatibility design are completed. The current sensor which can be used for practical measurement is developed. Finally, field test is carried out. The test results show that the developed current sensor can meet the measurement requirements of distributed current of reactor, which will provide an important technical means for real-time monitoring of dry-type air core reactor.

Published
2020

34. Study on electromagnetic shielding of the distributed current sensor for dry-type air-core reactor

Author

Yang Chao, Hao Changjin, Cui Zhigang, Qian Guochao, Liu Yi, and Liu Yang

Subjects
Electric power system, Nuclear engineering, Electromagnetic shielding, Process (computing), Environmental science, ComputerApplications_COMPUTERSINOTHERSYSTEMS, Current sensor, Overheating (economics), Sense (electronics), Current (fluid), Inductor
Abstract

Dry-type air-core reactor widely used in power systems is affected by many factors such as the manufacturing process, operating environment, insulation aging. The insulation performance has deteriorated, resulting in frequent fire accidents caused by local overheating during the switching process. The research results show that the insulation state of the reactor can be evaluated by measuring the distributed current of the reactor, so as to sense the operation failure of the reactor in advance. The magnetic radiation generated by the parallel structure of the dry-type air-core reactor is the main cause of the measurement error of the current detection device. Therefore, this paper conducts simulation research on the electromagnetic shielding device of the wireless distributed current sensors, makes the shielding device of distributed current sensors, then conducts field tests. The results show that the developed current sensor shielding device can well meet the requirements of the reactor distributed current measurement, which provides favorable conditions for the development of current sensors.

Published
2020

35. Simulation of gas diffusion in hollow-core photonic crystal fiber

Author

Qian Guochao, Peng Qingjun, Zhou Feng, Wang Jiaxua, Wang Jianxin, and Peng Hui

Subjects
Materials science, Microchannel, Single-mode optical fiber, Physics::Optics, Response time, 02 engineering and technology, Mechanics, 01 natural sciences, 010309 optics, 020210 optoelectronics & photonics, Diffusion process, 0103 physical sciences, 0202 electrical engineering, electronic engineering, information engineering, Fluid dynamics, Fiber, Diffusion (business), Photonic-crystal fiber
Abstract

Hollow-Core Photonic Crystal Fibers (HC-PCFs) have aroused great interest in the field of fiber-based gas sensing, where high sensitivity, fast response, and distribution sensing are required. One of the most important factors for gas sensing is the response time that the gas fills the hollow core of the fiber. In order to achieve rapid response for gas sensing, various techniques have been investigated in the literature, such as lateral drilled side holes. Though the gas concentration along the fiber at a certain time can be expressed, it do not give a satisfied explanation to the mechanism of gas flow in HC-PCFs drilled with side holes, which is essential to determine the optimum design parameters of the fiber sensor, such as the size and spacing of drilled side holes. This study aims to analyze the gas flow behavior and determine the response time of HC-PCFs with drilled side holes by developing and applying a numerical model based on gas diffusion in a microchannel. The diffusion takes place at the atmospheric temperature and pressure. Both ends of the HC-PCF are spliced to single mode fibers, the side holes whose diameter is 10 µm are open to the air. The open side holes are embraced with gas species, the transient diffusion process between the air and the gas species. The model is validated against the results of two different experimental studies. The model is then applied to determine the response time as a function of the length, the number and spacing of side holes. It is found that an inverse relationship exists between the effects of number and spacing of side holes on the response time, suggesting that an optimum design point exists. The results obtained can be utilized for the fiber sensor design.

Published
2020

50. The study on vibration characteristic of power transformer in short circuit by transfer function

Author

Zou Dexu, Qian Guochao, Fan Zhang, Shengchang Ji, and Xu Xiaowei

Subjects
Isolation transformer, Engineering, business.industry, Acoustics, Linear variable differential transformer, Electronic engineering, Energy efficient transformer, Distribution transformer, Transformer effect, business, Delta-wye transformer, Short circuit, Current transformer
Abstract

The vibration of power transformer is closely related to the mechanical condition of transformer and current when the external short circuit occurs. In this paper, the vibration sensors based on piezoelectric effect are attached to the oil tank of transformer to acquire the vibration signals in short circuit condition, and then the transfer function is applied to study the relationship between the vibration and short- circuit current under multiple short circuit shocks. Compared with traditional frequency domain or time- frequency domain analysis, this method can normalize the vibration in different short circuit condition and clearly illustrate the relationship between vibration and current. The conclusion shows that this method is feasible to evaluate the mechanical condition of transformer by using the correlation analysis of amplitude- frequency characteristic of transfer function in different short circuit condition.

Published
2015

Catalog

Books, media, physical & digital resources
See catalog results