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The fault simulation experiment and feature extraction of rolling bearing based on casing measuring point

The fault simulation experiment and feature extraction of ro...

Joint Conference on Machinery Failure Prevention Technology Conference, MFPT 2016 and ISA's 62nd International Instrumentation Symposium, IIS 2016

作者： Han, Te Jiang, Dongxiang Wang, Nanfei State Key Lab. of Control and Simulation of Power System and Generation Equipments Department of Thermal Engineering Tsinghua University Beijing100084 China

In this paper, the reliability of the rolling bearing fault feature extraction based on casing vibration signals is discussed. Through the fault simulation experiment of rolling bearing, the vibration data of the outer ring fault, inner ring fault and rolling element fault, which respectively comes from bearing block measuring point and casing measuring point, is acquired. Then this paper analyzed the data from the time domain, frequency domain and amplitude domain. Analysis results show that, compared to the bearing block measuring points, due to the attenuation of the pulse signal of the fault in the transmission way and the increase of signal to noise on the casing, the fault features of casing vibration signals are significantly weakened. The envelope demodulation, FFT change on the vibration signal of casing directly cannot extract the fault characteristics. However the fault characteristic frequency can be extracted from the appropriate resonance frequency band. The results provide a reference for the fault feature extraction of rolling bearing based on the signal of casing. © 2016, Society for Machinery Failure Prevention Technology. All rights reserved.

关键词： Roller bearings

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A novel method for energy storage sizing based on time and frequency domain analysis

A novel method for energy storage sizing based on time and f...

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2016 International Conference on Probabilistic Methods Applied to power systems, PMAPS 2016

作者： Tian, Liting Guo, Jianbo Cheng, Lin State Key Laboratory of Operation and Control of Renewable Energy and Storage System China Electric Power Research Institution Haidian District Beijing China Department of Electrical Engineering Tsinghua University Haidian District Beijing China

ISBN: (纸本)9781509019700

Energy storage is used to balance the variant power for the stability of the grid. It is significant to understand the fluctuation characteristic of renewable energy (RE) generation and the requirements of energy storage when large-scale RE is integrated in the grid. In the paper, a novel method based on time and frequency domain analysis is proposed for energy storage system (ESS) sizing, including both power sizing and energy sizing. According to the relationship between charge/discharge power and stored energy, the sizing model is established based on autocorrelation function and power spectral density (PSD) of the stochastic cycling process. The time and spectral characteristic of RE generation is analyzed based on the historical generation data of a wind farm and a PV station in the Northwest region of China. The size of energy storage is determined by the time and frequency domain method respectively. Comparing with the time domain method, it is showed that the frequency domain method is sufficient for energy storage sizing with enough accuracy and a much easier calculation process at the same time. © 2016 IEEE.

关键词： Energy storage

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Design of Rated power control Strategy of Wind Turbine Based on Particle Swarm Optimization

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IOP Conference Series: Earth and Environmental Science 2018年第1期192卷

作者： YC Yang Y Liu P Song Y Cui Y Bai Department of Control and Computer Engineering North China Electric Power University Beijing 102206 China North China Electric Power Research Institute Co. Ltd. Smart Grid and New Energy Institute Beijing 100045 China Grid-connected Operation Technology for Wind-Solar-Storage Hybrid System State Grid Corporation Key Laboratory

In view of the reduction of wind turbine operating efficiency caused by wind speed measurement errors, this paper proposes a rated power control strategy for wind turbines for practical applications; in order to solve the problem that the pitch PI controller parameters of wind turbines are not easy to calculate and tune in the process of design and optimization, this paper proposes a complete set of methods for parameter tuning of pitch control PI controllers for wind turbines. This paper establishes a Bladed-Matlab co-simulation platform, uses Bladed software to build a complete model of a 2MW wind turbine, and designs a rated power control strategy for wind turbines. After the wind turbine model is linearized at different wind speed points by applying Bladed software, the linearized model for PI parameter tuning is obtained, and then the optimal PI parameters for each wind speed point are set by using particle swarm algorithm. According to the variation law between the PI parameters and the pitch angle obtained before, the PI parameters are adjusted adaptively by variable gain PI control. The simulation results show the superiority of the control strategy and parameter tuning method used in this paper.

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Repeated Strike Process During Disconnector operation in Ultra-High Voltage Gas-Insulated Switchgear

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Plasma Science and Technology 2016年第3期18卷 247-253页

作者：关永刚蔡元纪陈维江刘卫东李志兵岳功昌张俊民 State Key Lab of Control and Simulation of Power System and Generation Equipments Department of Electrical EngineeringTsinghua UniversityBeijing 100084China State Grid Corporation of China Beijing 100031China China Electric Power Research Institute Beijing 100192China School of Automation Science and Electrical Engineering Beihang UniversityBeijing 100191China

Very fast transient over-voltage （VFTO）, induced by disconnector operations in gas- insulated switchgears, has become the limiting dielectric stress at ultra-high voltage levels. Much work has been done to investigate single-strike waveforms of VFTO. However, little study has been carried out investigating the repeated strike process, which would influence VFTO significantly. In this paper, we carried out 450 effective experiments in an ultra-high voltage test circuit, and conducted calculations through the Monte Carlo simulation method, to investigate the repeated strike process. Firstly, the mechanism of the repeated strike process is proposed, based on the ex- perimentai results. Afterwards, statistical breakdown characteristics of disconnectors are obtained and analyzed. Finally, simulations of the repeated strike process are conducted, which indicate that the dielectric strength recovery speed and polarity effect factor have a joint effect on VFTO. This study enhances the understanding of the nature of VFTO, and may help to optimize the disconnector designed to minimize VFTO.

关键词： disconnector （DS） repeated strike process discharge statistical breakdowncharacteristics ultra-high voltage （UHV） very fast transient over-voltage （VFTO）

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Production simulation of power systems considering the forecast error of renewable energy

Production simulation of power systems considering the forec...

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2016 IEEE PES Asia Pacific power and Energy Engineering Conference, APPEEC 2016

作者： Kun, Ding Ningbo, Wang Xie, Haipeng Bie, Zhaohong Laboratory of Wind Power Integration Operation and Control Gansu Electric Power Corporation Wind Power Technology Center Lanzhou China State Key Lab. of Elec. Insulation and Pwr. Equip. and Smart Grid Key Laboratory of Shaanxi Province Xi'an Jiaotong University Xi'an China

ISBN: (纸本)9781509054183

A short-term stochastic production simulation method considering the forecast error of renewable sources power is proposed to focus on the issue that conventional production simulation method is incapable of depicting the forecast error of renewable sources power. The proposed method contains two hierarchies, i.e. the day-ahead simulation and the real-time simulation. As for day-ahead simulation, a day-ahead scheduling of conventional units and renewable energy plants is determined by solving a unit commitment model on the basis of forecasted renewable sources power and load profiles. Real-time simulation is the supplement to day-ahead simulation and it corrects the results in day-ahead simulation. The validity of the proposed method is proved with a real power grid in Northwest China. Case studies show that conventional units may be still the major resource of power grids although these installed capacity is no larger than renewable energy resources. Meanwhile, forecast errors actually impact reliability of power systems. © 2016 IEEE.

关键词： Renewable energy resources

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Author Correction: Near-real-time monitoring of global CO2 emissions reveals the effects of the COVID-19 pandemic

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Nature communications 2020年第1期11卷 6292页

作者： Zhu Liu Philippe Ciais Zhu Deng Ruixue Lei Steven J Davis Sha Feng Bo Zheng Duo Cui Xinyu Dou Biqing Zhu Rui Guo Piyu Ke Taochun Sun Chenxi Lu Pan He Yuan Wang Xu Yue Yilong Wang Yadong Lei Hao Zhou Zhaonan Cai Yuhui Wu Runtao Guo Tingxuan Han Jinjun Xue Olivier Boucher Eulalie Boucher Frédéric Chevallier Katsumasa Tanaka Yiming Wei Haiwang Zhong Chongqing Kang Ning Zhang Bin Chen Fengming Xi Miaomiao Liu François-Marie Bréon Yonglong Lu Qiang Zhang Dabo Guan Peng Gong Daniel M Kammen Kebin He Hans Joachim Schellnhuber Department of Earth System Science Tsinghua University Beijing China. zhuliu@***. Laboratoire des Sciences du Climat et de l'Environnement LSCE CEA CNRS UVSQ Centre d'Etudes Orme de Merisiers Gif-sur-Yvette France. Department of Earth System Science Tsinghua University Beijing China. Department of Meteorology and Atmospheric Science The Pennsylvania State University University Park PA USA. Department of Earth System Science University of California Irvine 3232Croul Hall Irvine CA USA. Division of Geological and Planetary Sciences California Institute of Technology Pasadena CA USA. Jet Propulsion Laboratory California Institute of Technology Pasadena CA USA. Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control Collaborative Innovation Center of Atmospheric Environment and Equipment Technology School of Environmental Science and Engineering Nanjing University of Information Science and Technology Nanjing China. Key Laboratory of Land Surface Pattern and Simulation Institute of Geographical Sciences and Natural Resources Research Chinese Academy of Sciences Beijing China. Climate Change Research Center Institute of Atmospheric Physics Chinese Academy of Sciences Beijing China. Key Laboratory of Middle Atmosphere and Global Environment Observation Institute of Atmospheric Physics Chinese Academy of Sciences Beijing China. School of Environment Tsinghua University Beijing China. School of Mathematical School Tsinghua University Beijing China. Department of Mathematical Sciences Tsinghua University Beijing China. Center of Hubei Cooperative Innovation for Emissions Trading System Wuhan China. Faculty of Management and Economics Kunming University of Science and Technology 13 Kunming China. Economic Research Centre of Nagoya University Furo-cho Chikusa-ku Nagoya Japan. Institut Pierre-Simon Laplace Sorbonne Université/CNRS Paris France. Université Paris Dauphine Place du Maréchal de Lattre de Tassigny 75016 Paris France.

A Correction to this paper has been published: https://***/10.1038/s41467-020-20254-5.

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Risk assessment of cascading failures in power grid based on complex network theory

Risk assessment of cascading failures in power grid based on...

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International Conference on control, Automation, Robotics and Vision (ICARCV)

作者： Yanbing Jia Ruiqiong Liu Peng Wang Xiaoqing Han Shanxi Key Lab. of Power System Operation and Control Taiyuan University of Technology Taiyuan China School of Electrical & Electronic Engineering Nanyang Technological University Singapore

Cascading failure is an intrinsic threat of power grid to cause enormous cost of society, and it is very challenging to be analyzed. The risk of cascading failure depends both on its probability and the severity of consequence. It is impossible to analyze all of the intrinsic attacks, only the critical and high probability initial events should be found to estimate the risk of cascading failure efficiently. To recognize the critical and high probability events, a cascading failure analysis model for power transmission grid is established based on complex network theory (CNT) in this paper. The risk coefficient of transmission line considering the betweenness, load rate and changeable outage probability is proposed to determine the initial events of power grid. The development tendency of cascading failure is determined by the network topology, the power flow and boundary conditions. The indicators of expected percentage of load loss and line cut are used to estimate the risk of cascading failure caused by the given initial malfunction of power grid. Simulation results from the IEEE RTS-79 test system show that the risk of cascading failure has close relations with the risk coefficient of transmission lines. The value of risk coefficient could be useful to make vulnerability assessment and to design specific action to reduce the topological weakness and the risk of cascading failure of power grid.

关键词： power system faults power system protection power grids Load flow power transmission lines Complex networks

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Repeated Strike Process During Disconnector operation in Ultra-High Voltage Gas-Insulated Switchgear

Repeated Strike Process During Disconnector Operation in Ult...

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作者： Guan, Yonggang Cai, Yuanji Chen, Weijiang Liu, Weidong Li, Zhibing Yue, Gongchang Zhang, Junmin State Key Lab of Control and Simulation of Power System and Generation Equipments Department of Electrical Engineering Tsinghua University Beijing100084 China State Grid Corporation of China Beijing100031 China China Electric Power Research Institute Beijing100192 China School of Automation Science and Electrical Engineering Beihang University Beijing100191 China

Very fast transient over-voltage (VFTO), induced by disconnector operations in gas-insulated switchgears, has become the limiting dielectric stress at ultra-high voltage levels. Much work has been done to investigate single-strike waveforms of VFTO. However, little study has been carried out investigating the repeated strike process, which would influence VFTO significantly. In this paper, we carried out 450 effective experiments in an ultra-high voltage test circuit, and conducted calculations through the Monte Carlo simulation method, to investigate the repeated strike process. Firstly, the mechanism of the repeated strike process is proposed, based on the experimental results. Afterwards, statistical breakdown characteristics of disconnectors are obtained and analyzed. Finally, simulations of the repeated strike process are conducted, which indicate that the dielectric strength recovery speed and polarity effect factor have a joint effect on VFTO. This study enhances the understanding of the nature of VFTO, and may help to optimize the disconnector designed to minimize VFTO.

关键词： Monte Carlo methods

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Analysis of Fault Characteristics of Half-wavelength AC Transmission Lines

Analysis of Fault Characteristics of Half-wavelength AC Tran...

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IEEE power and Energy Society General Meeting

作者： Teng Feng Xinzhou Dong Bin Wang Shenxing Shi Shuxin Luo Aoyu Lei Lanxi Tang State Key Lab. of Control and Simulation of Power System and Generation Equipment Dept. of Electrical Engineering Tsinghua University

ISBN: (纸本)9781509041695

Half-wavelength AC transmission (HWACT) is an ultra-long distance AC transmission technology, whose electrical distance is close to half-wavelength at the system power frequency. The countries with a large territory have a big demand for HWACT. The fault characteristics of an HWACT line can be different from those of a conventional transmission line. So it is necessary and significant to analyze the fault characteristics of an HWACT line. In this paper, the influence of fault distances and fault resistances on the fault voltages and currents of two buses is analyzed after different types of faults occur on an HWACT line. And the analysis results are compared with the simulation results from EMTP.

关键词： Fault characteristics Fault distance Fault resistance Fault type Half-wavelength AC transmission fault resistance half-wave AC power transmission faults electrical distance power frequency Electromagnetic Transients Program fault signature Analysis

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A novel method for energy storage sizing based on time and frequency domain analysis

A novel method for energy storage sizing based on time and f...

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International Conference on Probabilistic Methods Applied to power systems (PMAPS)

作者： Liting Tian Jianbo Guo Lin Cheng State Key Laboratory of Operation and Control of Renewable Energy & Storage System China Electric Power Research Institution Beijing China Department of Electrical Engineering Tsinghua University Beijing China

ISBN: (纸本)9781509019717

关键词： Decision support systems Erbium Correlation Time-domain analysis Frequency-domain analysis

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