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Rolling bearing fault feature extraction of casing vibration signal

Rolling bearing fault feature extraction of casing vibration...

Society for Machinery Failure Prevention Technology Annual Conference 2017: 50 Years of Failure Prevention Technology Innovation, MFPT 2017

作者： Yang, Yizhou Jiang, Dongxiang State Key Lab of Control Simulation of Power Systems and Generation Equipment Department of Thermal Engineering Tsinghua University Beijing100084 China

The health of rolling bearing plays an important part in the operation of rotating machinery like gas turbine engine. Health monitoring and fault diagnosis of rolling bearings based on vibration signals have been through great development these years. But when sensors are set on the casing instead of the bearing pedestal, and the surrounding structure is very complex, the diagnosis problem becomes much more complicated, which brings more challenges to the signal processing. In this paper, a set of signal processing methods are used to enhance and extract the impact features from casing vibration signals, and to realize the detection of rolling bearing faults. Aself-adaptive decomposition method called intrinsic time-scale decomposition (ITD) is applied to decompose the vibration signal into a series of proper rotation components and a monotonic trend, helping to extract dynamic features of the signal. Teager-Kaiser energy operator is a simple algorithm calculating the energy of a signal and is very sensitive to transient impact faults. As the fault feature transmitted to the casing is relatively week, autoregressive model (AR) and minimum entropy deconvolution (MED) are to enhance the non-stationary impact components. Experiments are taken on the rotor-bearing-casing test rig with minor defects in themain shaft bearing. Testing on the casing vibration signal, this fault feature enhancing and extracting method shows its remarkable ability in rolling bearing fault diagnosis.

关键词： Feature extraction

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Degradation state assessment of rolling bearing based on variational mode decomposition and energy distribution 16th

Degradation state assessment of rolling bearing based on var...

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16th International Conference on Fracture and Damage Mechanics, 2017

作者： Han, Te Jiang, Dongxiang Yang, Wenguang State Key Lab of Control and Simulation of Power Systems and Generation Equipment Department of Thermal Engineering Tsinghua University Beijing100084 China

ISBN: (纸本)9783035711684

Degradation state assessment of bearing is an important part of prognostic and health management (PHM) in rotating machinery. Generally, the energy distribution of frequency band is sensitive to degradation state for rolling bearing. Hence, a novel assessment method based on variational mode decomposition (VMD) and energy distribution is proposed in this work. Firstly, the VMD is used to decompose raw vibration signal into several components with different scales and frequency bands. These components is capable of reflecting the local characteristic of vibration signal. Then, the energy distribution of these components is utilized as feature vector. Finally, the different bearing states can be classified by the scatter plots of the first several principal components after principal component analysis (PCA). The analysis of an experimental dataset demonstrates the effectiveness of this methods. The comparative analysis shows the VMD is superior to traditional empirical mode decomposition (EMD) methods. © 2017 Trans Tech Publications, Switzerland.

关键词： Variational mode decomposition

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Steady-state security analysis of power system based on the operational reliability theory 3

Steady-state security analysis of power system based on the ...

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3rd International Conference on Reliability of Electrical Products and Electrical Contacts, ICREPEC 2009

作者： Zou, Xin Cheng, Lin Sun, Yuanzhang Department of Electrical Engineering State Key Lab of Control and Simulation of Power Systems and Generation Equipments Tsinghua University Beijing100084 China

ISBN: (纸本)9789889968489

Conventional steady-state security analysis have to compute the faults belonging to the predefined faults set in turn with out considering the small probability of the occurrence of some faults under certain circumstances. Although its results reflect the violation of the components precisely, they can not figure out how the violation affects the security of the system. The steady-state security analysis based on the operational reliability theory applies the state-depended models of the components in order to find the faults which would happen with high probability. As a result, only these faults should be calculated to decrease the computation time considerably. Further more, the reliability indices indicate the probability of the violation of the component as well as the influence of the violation on the system security, so that the security of the system can be evaluated comprehensively. IEEE RTS-79 test system is adopted in this paper to illustrate the differences between the conventional and the new steady-state security analysis methods. By contrast, it can be concluded that steady-state security analysis based on the operational reliability theory can calculate the influence of the variation of the component failure probability on the system security more specifically, which making the evaluation results more close to the practical operating system Copyright © 2009 by International Academic Publishers Ltd.

关键词： Reliability theory

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Efficient learning of robust quadruped bounding usingpretrained neural networks

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IET Cyber-systems and Robotics 2022年第4期4卷 331-338页

作者： Zhicheng Wang Anqiao Li Yixiao Zheng Anhuan Xie Zhibin Li Jun Wu Qiuguo Zhu Institute of Cyber-Systems and Control Zhejiang UniversityZhejiangChina Intelligent Robot Research Center Zhejiang LabZhejiangChina Department of Computer Science University College LondonLondonUK State Key Laboratory of Industrial Control Technology Zhejiang UniversityZhejiangChina

Bounding is one of the important gaits in quadrupedal locomotion for negotiating *** authors proposed an effective approach that can learn robust bounding gaits more efficiently despite its large variation in dynamic body *** authors first pretrained the neural network(NN)based on data from a robot operated by conventional model-based controllers,and then further optimised the pretrained NN via deep reinforcement learning(DRL).In particular,the authors designed a reward function considering contact points and phases to enforce the gait symmetry and periodicity,which improved the bounding *** NN-based feedback controller was learned in the simulation and directly deployed on the real quadruped robot Jueying Mini successfully.A variety of environments are presented both indoors and outdoors with the authors’*** authors’approach shows efficient computing and good locomotion results by the Jueying Mini quadrupedal robot bounding over uneven *** cover image is based on the Research Article Efficient learning of robust quadruped bounding using pretrained neural networks by Zhicheng Wang et al.,https://***/10.1049/csy2.12062.

关键词： legged locomotion reinforcement learning robot learning

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Applications and Prospects of Online Insulation Monitoring Technique Based on Broadband Frequency Response for Transformers in Voltage Source Converter System 2nd

Applications and Prospects of Online Insulation Monitoring T...

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Conference Proceedings of 2022 2nd International Joint Conference on Energy, Electrical and Power Engineering

作者： Lu, Geye Zheng, Dayong Zhang, Pinjia State Key Lab of Security Control and Simulation of Power Systems and Large Scale Generation Equipment Tsinghua University Beijing100084 China

ISBN: (纸本)9789819943333

Power electronic converters are widely applied in new power system. Converter transformers have a critical risk in safe and reliable operation due to the insulation ageing. At present, conventional transformer insulation monitoring methods are limited to low sensitivity, invasive sensors and sophisticated evaluation. The goal of this paper is to improve the performance of online insulation monitoring for converter transformers based on broadband frequency response. The significance of application promotion, the disadvantages of existing methods and the challenges from offline to online implementation are clarified. A novel technique based on inherent harmonics in voltage source converter system is investigated, which provides the prospect in improving the online monitoring performance with high reliability and non-invasiveness nature. © 2023, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.

关键词： Insulation

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Evaluation of cascading failure in power system based on the operational reliability theory

Evaluation of cascading failure in power system based on the...

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2010 IEEE 11th International Conference on Probabilistic Methods Applied to Power systems, PMAPS 2010

作者： Zou, Xin Cheng, Lin Sun, Yuanzhang Department of Electrical Engineering State Key Lab. of Control and Simulation of Power Systems and Generation Equipments Tsinghua University Beijing China

ISBN: (纸本)9781424457236

According to the characteristics of the cascading failures in power grid, a lot of assessment methods based on the probability theory have been proposed in recent years. However, most of them ignore the influence of the changing operating conditions on the power system planning and operation. This paper assesses the risk of the cascading failure in the power system based on the operational reliability theory which considering the variation of operating states and environment of the power system. The operational reliability of the power system is calculated based on Markov Process which describes the transient probability of states. The key conception of this theory is that the failure rate and the probability of components are changing along with the life of the equipment, the operating states and the environment conditions. A new evaluation procedure is brought up to calculate the operational reliability indices which can provide the specific information of the cascading failure. The evaluating results of the test system confirm that this approach is applicable to analyze the cascading failures in real power system. ©2010 IEEE.

关键词： Reliability theory

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Research of algorithm and analysis of performance for DC surge impedance relay

Research of algorithm and analysis of performance for DC sur...

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12th IET International Conference on Developments in Power System Protection, DPSP 2014

作者： Lei, Aoyu Dong, Xinzhou State Key Lab of Control and Simulation of Power Systems and Generation Equipments Department of Electrical Engineering Tsinghua University Beijing 10084 China

Surge Impedance Relay(SIR) is applied to DC system. Characteristics of SIR in DC line are analysed. A DC SIR algorithm implementing wavelet transform applied to HVDC line protection is proposed. The feasibility of DC ... 详细信息

ISBN: (纸本)9781849198349

关键词： Wavelet transforms

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Expression and function analysis of the metallo-thionein-like (MT-like) gene from Festuca rubra in Chlamydomonas reinhardtii chloroplast

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Science China(Life Sciences) 2008年第12期51卷 1076-1081页

作者： HAN SiHai1,2, HU ZhangLi1 & LEI AnPing1 1 Institute of Eco-Environment, College of Life Science, Shenzhen University, Shenzhen 518060, China 2 Research Center for Analytical Instrumentation, State key lab of Industrial control Technology, Institute of Cyber-systems and control, Zhejiang University, Hangzhou 310058, China 1. Institute of Eco-Environment College of Life Science Shenzhen University Shenzhen 518060 China 2. Research Center for Analytical Instrumentation State Key Lab of Industrial Control Technology Institute of Cyber-Systems and Control Zhejiang University Hangzhou 310058 China

The cDNA of the metallothionein-like (MT-like) gene from Festuca rubra cv. Merlin was optimized with bias codon of Chlamydomonous reinhardtii chloroplast genome. The optimized MT-like gene was de-livered into C. reinhardtii chloroplast and the transgenic strains expressing MT-like gene was obtained. PCR-Southern blot and RT-PCR-Southern blot analysis demonstrated that the MT-like gene was inte-grated into chloroplast genome of C. reinhardtii and expressed at the transcriptional level. The cad-mium binding capacity of the transgenic C. reinhardtii was determined by hydride generation-atomic fluorescence spectrometry (HG-AFS) and the binding properties were analyzed. Results showed that the transgenic C. reinhardtii expressing the MT-like gene exhibited remarkably higher Cd2+ binding capacity and grew to higher densities at toxic Cd2+ concentrations (40-100 μmol/L) than the wild type strain, and that the IC50 of Cd2+ (3-d treating ) to algal cell growth of transgenic strain was 55.43% higher than that of the wild type strain, indicating that the Cd2+ binding capacity and Cd2+ tolerance of C. reinhardtii was enhanced through the expression of the foreign MT-like gene in chloroplast.

关键词： Chlamydomonas reinhardtii chloroplast metallothionein-like (MT-like) gene cadmium binding properties

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A usage-based transmission cost allocation scheme considering impacts of DERs

A usage-based transmission cost allocation scheme considerin...

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2016 Tsinghua University-IET Electrical Engineering Academic Forum

作者： Wang, J.X. Zhong, H.W. Xia, Q. State Key Lab. of Control and Simulation of Power Systems and Generation Equipments Department of Electrical Engineering Tsinghua University Beijing China

ISBN: (纸本)9781785614170

With the rapid development of distributed energy resources (DERs), it is of vital importance to develop a well-designed transmission cost allocation scheme to reflect the contributions of DERs to the power system. In this paper, a usage-based transmission cost allocation scheme is proposed considering the capability of DERs. Based on the different intentions of transmission capacity, the transmission costs can be classified into four fractions: operating, contingency, planning and invalid transmission costs. On operating conditions, the transmission costs are identified and allocated according to the actual usage of consumers at each node. On contingency conditions, the transmission cost allocation will be influenced by the behaviors of DERs since DERs can provide emergent power support to help alleviate transmission congestion. On planning conditions, the transmission costs are useful in the future. The residual costs, i.e., the invalid transmission costs, should not allocated by consumers because this fraction is caused by the over investment of transmission owners. The case studies based on the IEEE 30-bus system validates the effectiveness of the proposed scheme and model. © 2016, Institution of Engineering and Technology. All rights reserved.

关键词： Investments

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Simulation and feature extraction of inter-shaft bearing fault in rotor-bearing-casing system 26

Simulation and feature extraction of inter-shaft bearing fau...

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26th International Congress on Sound and Vibration, ICSV 2019

作者： Yang, Yizhou Liu, Chao Jiang, Dongxiang Han, Te State Key Lab of Control and Simulation of Power Systems and Generation Equipment Department of Thermal Engineering Tsinghua University Beijing100084 China

ISBN: (纸本)9781999181000

The inter-shaft bearing could simplify the supporting structure of a dual-rotor system, so it is widely used in rotating machinery like gas turbine engine. When monitoring the vibration of an inter-shaft bearing, sensors usually could not be installed inside the engine because of the compact structure, then will be installed on the casing. The vibration of the inter-shaft bearing will be transmitted though both the two rotors to the supporting bearings then to the casing, and both the inner and outer ring rotate, making the condition monitoring much more difficult than normal bearings. In this paper, a dual-rotor system dynamic model with the rotor-bearing-casing structure is built to simulate the vibration of an inter-shaft bearing. The rotors and the casing are modelled using finite element method and the bearings are modelled using a nonlinear multi-body dynamic model. The normal state of the inter-shaft bearing is simulated, then the bearing fault states with localized defects on the inner race, the outer race and one of the rolling elements are simulated. Signal processing methods are utilized to extract bearing fault features from the casing vibration acceleration signal. Besides the fixed rotating speed condition, rotors under variable speeds are also simulated, then the vibration signal and fault feature become more complex and the signal analysis becomes a bigger challenge © Proceedings of the 26th International Congress on Sound and Vibration, ICSV 2019. All rights reserved.

关键词： Dynamic models

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