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Statistical characteristics of transient enclosure voltage in ultra-high-voltage gas-insulated switchgear

Plasma Science and Technology 2017年第6期19卷 74-81页

作者： Yuanji CAI Yonggang GUAN Weidong LIU State Key Lab of Control and Simulation of Power System and Generation Equipment Department of Electrical Engineering Tsinghua University Beijing 100084 People＇s Republic of China

Transient enclosure voltage（TEV）,which is a phenomenon induced by the inner dielectric breakdown of SF_6 during disconnector operations in a gas-insulated switchgear（GIS）,may cause issues relating to shock hazard and electromagnetic interference to secondary *** is a critical factor regarding the electromagnetic compatibility of ultra-high-voltage（UHV）*** this paper,the statistical characteristics of TEV at UHV level are collected from field experiments,and are analyzed and compared to those from a repeated strike *** TEV waveforms during disconnector operations are recorded by a self-developed measurement system ***,statistical characteristics,such as the pulse number,duration of pulses,frequency components,magnitude and single pulse duration,are *** transmission line theory is introduced to analyze the TEV and is validated by the experimental ***,the relationship between the TEV and the repeated strike process is *** proves that the pulse voltage of the TEV is proportional to the corresponding breakdown *** results contribute to the definition of the standard testing waveform of the TEV,and can aid the protection of electronic devices in substations by minimizing the threat of this phenomenon.

关键词： transient enclosure voltage (TEV) gas-insulated switchgear (GIS) ultra-high-voltage (UHV) repeated strike process disconnector

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High resistance grounding fault feeder detection in a resonant grounding system based on transient current correlation coefficient comparison 8

High resistance grounding fault feeder detection in a resona...

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8th Renewable power generation Conference, RPG 2019

作者： Cui, Xin Wang, Bin Dong, Xinzhou Key Lab of Control and Simulation of Power Systems and Generation Equipment Department of Electrical Engineering Tsinghua University Beijing100084 China

ISBN: (纸本)9781839531255

Because the fault characteristics is not obvious, the high resistance grounding fault feeder selection in a resonant grounding system has always been a hot and difficult problem in the field of power system protection. To solve this problem, the expressions of the transient zero sequence current of each feeder under over-damping and under-damping conditions are obtained based on the transient equivalent circuit of high resistance grounding fault in a resonant grounding system. The correlation degree of the transient zero sequence current between any two feeders is analysed by using the correlation coefficient method, so as to realize the fault feeder selection for high resistance grounding fault. simulation results of PSCAD software show that this method is not affected by transition resistance, initial phase angle of fault, and has high accuracy and reliability. © 2019 Institution of Engineering and Technology. All rights reserved.

关键词： Damping

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Life prediction and reliability analysis of motorbearing based on vibration signal 7

Life prediction and reliability analysis of motorbearing bas...

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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

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An Improved OPA Model in power System Considering Planning 33

An Improved OPA Model in Power System Considering Planning

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第三十三届中国控制会议

作者： GONG Yuan MEI Shengwei PENG Dong LONG Wangcheng GUO Mingxing Power Systems and Power Generation Equipment Control and Simulation National Key Laboratory Department of Electrical Engineering Tsinghua University State Power Economic Research Institute

ISBN: (纸本)9781479947249

The power system now is a typical complex system, which has inherent characteristics of SOC. Studying on cascading failures are necessary and meaningful to insure the grid's safety, national security and economic development. This paper firstly establishes the indices of power system development diagnosis, which are closely relevant to the trigger of power system evolution. Then a cascading failure model is proposed, considering planning and evolution of the power system. This model is based on OPA model, including both fast dynamics and slow dynamics. The slow dynamic process simulates the evolution of power system, which represents the functions of the planning department, while the fast dynamic process simulates power flow and cascading failures, which takes the effects of dispatch, relay protection and automation into consideration. Moreover, simulations are tested on the case of Kaifeng-Shangqiu power system in Henan Province of China, and evolution results are presented.

关键词： power system evolution,cascading failure,power system diagnosis,power grid complexity,OPA model

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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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Rolling bearing fault feature extraction of casing vibration signal

Rolling bearing fault feature extraction of casing vibration...

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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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Research and simulation on voltage stability control strategy for AC port of power electronic transformer 16

Research and simulation on voltage stability control strateg...

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16th IET International Conference on AC and DC power Transmission, ACDC 2020

作者： Shen, Yu Nie, Haozhe Cai, Weiqian Yuan, Liqiang Zhang, Chunpeng Zhao, Zhengming State Key Lab of Control and Simulation of Power Systems and Generation Equipment Department of Electrical Engineering Tsinghua University Beijing100084 China

ISBN: (纸本)9781839533914

With wide application of power electronic equipment in power system, voltage stability and power supply reliability need to be improved. In this paper, voltage sag caused by AC port load increase and the influencing factors are studies with a typical power electronic transformer topology as example. A calculation method which can estimate the port voltage sag performance according to the load impedance is proposed. In order to maintain the port voltage stability in the process of load increase, a voltage stability control strategy is proposed based on the double-loop control by increasing the voltage feedforward, which can improve the power supply quality and stability of power electronic transformer. Finally, the MATlab/Simulink simulation results show that the proposed scheme is accurate and effective. © 2020 Institution of Engineering and Technology. All rights reserved.

关键词： MATlab

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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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Evaluation Method of Wind power Consumption Limitation in power System with High Proportion of Wind power 4

Evaluation Method of Wind Power Consumption Limitation in Po...

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4th IEEE China International Electrical and Energy Conference, CIEEC 2021

作者： Wang, Hongye He, Li Lin, Xuelong Ma, Jing An, Baihui Yang, Weixiang Xu, Fei Hou, Tao Li, Jing Feng, Changsheng Li, Junhui Co. Ltd Beijing China State Key Lab of Control and Simulation of Power Systems and Generation Equipment Tsinghua University Beijing China

ISBN: (纸本)9781728171494

In order to study the reasonable capacity of power grid to absorb wind power, a new calculation method is proposed for the combined system of thermal power and wind power. In this paper, the probability and statistics method is used to analyze the output characteristics of wind farm, and the influence of characteristic index on wind farm is studied. A new calculation method of wind power limit is proposed, and the influence of seasonal factors is introduced to study the situation of wind power limit in summer and winter. Through the actual example, the idea and method are provided to formulate the control principle of wind power output, and the rationality and effectiveness of the proposed method are verified. © 2021 IEEE.

关键词： Electric power utilization

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