检索结果-内蒙古大学图书馆

7th International Conference on Reliability of Electrical Products and Electrical Contacts, ICREPEC 2019

作者： Xu, Helin Cheng, Lin Wan, Yuxiang Qi, Ning State Key Laboratory of Control and Simulation of Power Systems and Generation Equipment Tsinghua University Beijing100084 China

ISBN: (纸本)9789881532343

As an important power equipment in the power system, the electrialc motor is an important part of the transformation of electric energy and mechanical energy. Reasonable prediction of the reliability level of the running motor, timely and effectively avoid the operational risks, can effectively ensure the safety and stable operation of the power system. This paper starts with the motor vibration signal and establishes the remaining life prediction based on SVM(Support Vector Machine). Firstly, the vibration signal is denoised by wavelet transform, and the characteristic parameters such as mean square value is extracted after signal data reconstruction. Further, combined with the characteristic value, the working state is divided, and the support vector machine regression prediction model is used to obtain the remaining life of the bearing. In the case study part, data denoising and feature extraction are performed on the bearing vibration data measured by the PRONOSTIA test bench. The trend of the selected characteristic values is used for evaluating the motor operating state. The characteristic value, running state of the equipment, and remaining life which are extracted from the training set data are input to the SVM, and then the SVM is used to predict the remaining life for the test set. Finally, failure rate of the equipment can be derived. © 2019 by International Academic Publishers Ltd.

关键词： Reliability analysis

来源：评论

学校读者我要写书评

暂无评论

Influences of temperature on Space Charge in Gas-to-Liquid Oil-Impregnated Paper

Influences of temperature on Space Charge in Gas-to-Liquid O...

引用

International Conference on High Voltage Engineering and Application, ICHVE

作者： Yuanxiang Zhou Xin Huang Ling Zhang Yunxiao Zhang Zhongliu Zhou Chenyuan Teng China State Key Laboratory of Control and Simulation of Power Systems and Generation Equipment Tsinghua University Beijing China

ISBN: (数字)9781728155111

ISBN: (纸本)9781728155128

Gas-to-liquid (GTL) transformer oil has been on trial in converter transformers. However, its influence on the space charge characteristic is not clear. This work aims at exploring space charge characteristics of GTL oil at different temperatures as well as comparing with commercial naphthenic oil (KI50X). Space charge distribution during the polarization and the dissipation process in the GTL oil-impregnated paper at different temperature was measured by the pulse electroacoustic method (PEA), which were contrasted with those of the KI50X oil-impregnated paper. Results illustrated that high temperature accelerated the injection and migration of charge carriers in the oil-impregnated paper. And the polarity of the accumulated charge in the vicinity of anode changed from positive to negative with the increase of temperature. It was perceived that oil-paper conductivity and carrier mobility grew with the increase of temperature, resulting in the easier migration of injected charge to another electrode. Furthermore, the space charge dissipation rate in the GTL oil-impregnated paper is lower than that in the naphthenic oil-impregnated paper at the same temperature. Thus, a longer time interval of tests or switch operation in the factory test and operation process may need if GTL oil is used rather than naphthenic oil.

关键词： Oils Space charge power transformer insulation Oil insulation Electric fields Distortion Temperature measurement

来源：评论

学校读者我要写书评

暂无评论

simulation Modeling and AC system Fault control Strategy for the Multi-terminal Hybrid HVDC system based on RTDS

Simulation Modeling and AC System Fault Control Strategy for...

引用

2019 IEEE Sustainable power and Energy Conference, iSPEC 2019

作者： Lin, Xuehua Guo, Qi Guo, Haiping Huang, Libin Chen, Qinlei Li, Shuyong Electric Power Research Institute State Key Laboratory of HVDC China Southern Power Grid Guangzhou510663 China CSG Key Laboratory for Power System Simulation Electric Power Research Institute China Southern Power Grid Guangzhou510663 China

ISBN: (纸本)9781728149301

A multi-terminal hybrid HVDC transmission system, with LCC station in the rectifier and MMC station in the inverter, integrates the advantages of LCC and MMC technology, and it overcomes the commutation failure problem in the inverter. The application includes power supply to weak AC system, passive load, islands and so on. It shows widely application prospect in the field of large capacity, high voltage and long distance HVDC transmission in the future. In this paper, firstly, the mathematical model for a multi-terminal hybrid HVDC transmission system is studied deeply, and its real time simulation system is established in RTDS. Then, a DC voltage margin control strategy for LCC in rectifier, and a transient AC voltage regulation strategy for MMC in inverter is put forward for dealing the AC system fault. The simulation results in RTDS show the control strategy is effective, and the DC voltage and transmission power recovery quickly after AC system series fault. The proposed control strategy is significant for the safety and reliability for the multi-terminal hybrid HVDC. © 2019 IEEE.

关键词： Electric inverters

来源：评论

学校读者我要写书评

暂无评论

A New Method for On-line Measurement of the Straightness Error of Machine Tools Using an Acceleration Sensor

Research Square

引用

Research Square 2021年

作者： Liu, Kuo Cui, Yiming Liu, Zhisong Wu, Jiakun Wang, Yongqing Key Laboratory for Precision and Non-traditional Machining Technology Ministry of Education Dalian University of Technology Dalian116024 China The Key Laboratory of Vibration Control of Aero-propulsion System Northeastern University Shenyang110819 China State Key Laboratory of Fluid Power Transmission and Control Zhejiang University Hangzhou310027 China

In order to improve the poor efficiency in the measurement of the geometric error of machine tools’ linear axes, this paper has presented a method to measure and restructure the geometric error of linear axes that is based on accelerometers. This method takes advantage of the phenomenon that when acceleration is measured under different measuring speeds, different frequencies and amplitudes are produced. The measurement data of the high signal-to-noise ratio for various velocities was fused together and the straightness error of the measured axis was obtained by integrating the acceleration twice. In order to remove the trend terms error in the integration, a zero phase IIR Butterworth filter was designed, which guarantees the signal’s phase invariance after filtering. The data was continued with the AR model to eliminate the endpoints’ effect in the filtering. The proposed method was verified by numerical values and experiments. The results showed that the proposed method has better robustness, a wider bandwidth and a higher efficiency than the methods of measuring by laser interferometer. It is also able to measure the geometric error of linear axes with an accuracy that reaches the micron scale. © 2021, CC BY.

关键词： Errors

来源：评论

学校读者我要写书评

暂无评论

The Optimal Design of the Second-Order Generalized Integrator Phase-Locked Loop Under power Voltage Distortion Conditions

The Optimal Design of the Second-Order Generalized Integrato...

引用

IEEE Conference on Energy Internet and Energy system Integration (EI2)

作者： Xin Zhang Lijiao Gong Bin Wang Jindong Si College of Mechanical and Electrical Engineering (Shihezi University) Shihezi China Key Laboratory of Northwest Agricultural Equipment College of Mechanical and Electrical Engineering (Shihezi University) Ministry of Agriculture and Rural Affairs (Shihezi University) Shihezi China State Key Laboratory of Safety Control and Simulation of Power Systems and Power Generation Equipment Tsinghua University Beijing China

ISBN: (纸本)9781665434263

Phase-locked loop (PLL) based on traditional second-order generalized integrator (SOGI) cannot obtain the voltage, frequency and phase information accurately when there are multiple harmonic interference and DC offset in grid voltage. To solve this problem, this paper proposes an improved PLL that can suppress harmonic and eliminate DC component to extract the synchronous signal accurately. First of all, based on the derivation of distorted grid voltage expression, the problem of fluctuation in extracting synchronous signal from three-phase unbalanced voltage with harmonic by traditional PLL is analyzed. Then, the design of improved PLL is proposed, which is composed of an improved second-order generalized integrator and a frequency correction component which can suppress harmonics and eliminate disturbances under the condition of grid voltage distortion, and has self-adaptability in large frequency offset. Determine the control parameters to ensure that the proposed PLL structure has a better rejection to harmonic distortion than previous approaches, and realize accurate tracking of grid fundamental frequency synchronization information. Finally, the behavior of the proposed system is verified with MATLAB/Simulink simulation and Hardware-in-Loop Experimental Platform which prove the proposed PLL can realize the synchronous tracking performance of grid frequency and phase quickly and accurately in the non-ideal grid environment, and the results are consistent with the theoretical analysis.

关键词： Analytical models Transient response Voltage Harmonic analysis Harmonic distortion Phase locked loops Frequency synchronization

来源：评论

学校读者我要写书评

暂无评论

power system transient stability margin assessment using steady-state information

Power system transient stability margin assessment using ste...

引用

2019 IEEE PES Innovative Smart Grid Technologies Asia, ISGT 2019

作者： An, Jun Mu, Gang Li, Zonghan Liu, Daowei Key Laboratory of Modern Power System Simulation and Control and Renewable Energy Technology Ministry of Education Jinlin China China Electric Power Research Institute Beijing China

ISBN: (纸本)9781728135205

Transient stability margin assessment provides power grid dispatchers with important criteria for decision-making and preventive control. The computational efficiency of online transient stability margin assessment can be largely improved with the use of steady-state information. In this paper, we propose a novel methodology for online stability margin assessment. A multi-swing based strategy that overcomes the false identification issues of previous methods is firstly illustrated. Based on this improved strategy, a composite neural network is constructed and trained offline to establish the mapping relationship between steady-state characteristics and generator transient stability indices. Finally, the trained neural network is utilized for online transient stability margin assessment. The major advantage of the proposed methodology is that we only use steady-state information in the online assessment process therefore system transient stability margin under worst disturbances can be fast and accurately predicted, providing system dispatchers with adequate time for preventive control. The validity of the proposed methodology is demonstrated in the IEEE 39-bus system. © 2019 IEEE.

关键词： Computational efficiency

来源：评论

学校读者我要写书评

暂无评论

A comparative thermodynamic analysis of Kalina and organic Rankine cycles for hot dry rock:a prospect study in the Gonghe Basin

引用

Frontiers in Energy 2020年第4期14卷 889-900页

作者： Xuelin ZHANG Tong ZHANG Xiaodai XUE Yang SI Xuemin ZHANG Shengwei MEI State Key Laboratory of Control and Simulation of Power System and Generation Equipments Department of Electrical EngineeringTsinghua UniversityBeijing 100084China Jingjing Energy Storage Co. Ltd.Changzhou 213200China School of QiDi(TUS)Renewable Energy Qinghai UniversityXining 810016China

Hot dry rock is a new type of geothermal resource which has a promising application prospect in *** paper conducted a comparative research on performance evaluation of two eligible bottoming cycles for a hot dry rock power plant in the Gonghe *** on the given heat production conditions,a Kalina cycle and three organic Rankine cycles were tested respectively with different ammonia-water mixtures of seven ammonia mass fractions and nine ecofriendly working *** results show that the optimal ammonia mass fraction is 82%for the proposed bottoming Kalina cycle in view of maximum net power *** analysis suggests that wet fluids should be supercritical while dry fluids should be saturated at the inlet of turbine,*** maximum net power output of the organic Rankine cycle with dry fluids expanding from saturated state is higher than that of the other organic Rankine cycle combinations,and is far higher than the maximum net power output in all tested Kalina cycle *** the given heat production conditions of hot dry rock resource in the Gonghe Basin,the saturated organic Rankine cycle with the dry fluid butane as working fluid generates the largest amount of net power.

关键词： hot dry rock Kalina cycle organic Rankine cycle thermodynamic analysis

来源：评论

学校读者我要写书评

暂无评论

Space Charge Characteristics of Oil-paper under AC/DC Composite Voltage

Space Charge Characteristics of Oil-paper under AC/DC Compos...

引用

Conference on Electrical Insulation and Dielectric Phenomena, (CEIDP)

作者： Yuanxiang Zhou Xin Huang Ling Zhang Yunxiao Zhang Zhongliu Zhou Chenyuan Teng Lei Xue Meng Huang The Wind Solar Storage Division of State Key Laboratory of Power System and Generation Equipment School of Electrical Engineering Xinjiang University Urumqi China China State Key Laboratory of Control and Simulation of Power Systems and Generation Equipment Tsinghua University Haidian Beijing China State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources North China Electric Power Universiy Beijing China

ISBN: (纸本)9781728195728;9781728195735

Oil-paper insulation bears AC/DC composite voltage in converter transformers. However, the AC/DC space charge behavior is still not clear, which will result in electric field distortion, material aging and even insulation failure. In this work, the space charge distribution of oil-paper under the AC/DC composite voltage with the AC/DC ratio of 1:1, 1:3, 1:5, and 1:7, is studied by pulse electroacoustic (PEA) method, respectively. It was found that as DC component increases, the accumulated charge near the electrode decreases, while the interior charge increases. It suggests that DC stress mainly influences the amount and the depth of space charge accumulation. AC component has a relatively significant impact on the injection and extraction behavior of space charge near the electrode. Furthermore, AC/DC composite voltage enhances the migration of space charge compared with that under DC voltage. This research contributes to the further understanding of the space charge characteristics of oil-paper under AC/DC composite voltage, which will benefit the safe and stable operation of converter transformers.

关键词： Electrodes Conferences Space charge Oil insulation Aging Distortion Dielectrics

来源：评论

学校读者我要写书评

暂无评论

Efficient Hydrogenation of P-Chlorophenol and Cr(Vi) Driven by Hydrogen Rich Balls Over Pd/C Catalysts

SSRN

引用

SSRN 2022年

作者： Niu, Junfeng Zhang, Yuanzheng Xu, Lei Pei, Yuansheng Niu, Junfeng Wang, Weilai Ministry of Education Key Laboratory for Yellow River and Huai River Water Environment and Pollution Control School of Environment Henan Normal University Henan Xinxiang453007 China State Key Laboratory of Water Environment Simulation School of Environment Beijing Normal University Beijing100875 China College of Environmental Science and Engineering North China Electric Power University Beijing102206 China Dongguan University of Technology China

Catalytic hydrogenation can selectively destabilize and detoxify specific contaminants in water. Guided by the adsorption-activation hydrogenation mechanism, carrier selection and active center construction have become the main content of hydrogenation catalyst research. However, this relies heavily by the development of new materials and technologies. Herein, from the perspective of hydrogen source, hydrogen rich balls (HRBs) were used to supply H2 for hydrogenating p-chlorophenol and Cr(VI) over Pd/C catalyst. The results showed that HRBs can realize the sustained release of H2 (14±2 µL/min·g) by replacing the hydrogen in water, and generate the refined (micro/nano-sized) H2 bubble, which effectively improves the adsorption and activation effectively of H2 molecules on Pd/C catalyst, and the hydrogen atoms utilization efficiency during p-chlorophenol hydrodechlorination is as high as 3.5%. Continuous flow experiments showed that rapid removal of p-chlorophenol with different concentrations could be achieved by adjusting the flow rate. Moreover, the high-toxic Cr(VI) was successfully reduced to the low-toxic Cr(III) by molecular hydrogen and active hydrogen in an appropriate pH range. This research is of far-reaching significance for realizing the detoxification of environmental pollutants and promoting the development of hydrogen economy. © 2022, The Authors. All rights reserved.

关键词： Atoms

来源：评论

学校读者我要写书评

暂无评论

Research on Fault Diagnosis Method of Distributed power Distribution Network Based on HHT and CNN

Research on Fault Diagnosis Method of Distributed Power Dist...

引用

第33届中国控制与决策会议

作者： Xiaodong Sun Huanxin Guan Yan Zhao Tieyan Zhang Yuri Wang Bo Yang School of Electric Power Shenyang Institute of Engineering State School of Renewable Energy Shenyang Institute of Engineering Key Laboratory of Regional Multi-energy System Integration and Control Liaoning Province School of Automation and Electrical Engineering Shenyang Ligong University State Grid Zhangye Power Supply Company

Accurate and reliable fault diagnosis is very important for improving relay protection performance and ensuring safe and stable operation of power *** paper presents a fault diagnosis method for distributed power distribution network based on convolutional neural *** fault occurs in the distribution network,FTU acquisition unit is used to sample the fault current and voltage signals of the distribution ***-Huang transform is applied to the fault signal,and a two-dimensional time-frequency energy matrix is *** the time-frequency energy matrix is input into the convolutional neural network to realize the fault type identification of transmission lines in the distribution network with distributed power *** simulation results show that the model in this paper improves the speed of fault diagnosis,makes the model more robust,and can determine and judge fault types more accurately and quickly.

关键词： power Distribution system with Distributed power Hilbert-Huang Transform Convolutional Neural Network Fault Classification

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：