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13th International Conference on Development in power system Protection 2016, DPSP 2016

作者： Tang, Lanxi Dong, Xinzhou Shi, Shenxing Wang, Bin State Key Laboratory of Control and Simulation of Power System and Generation Equipments Dept of Electrical Engineering Tsinghua University Beijing China

ISBN: (纸本)9781785618260

Travelling wave (TW) differential protection fully utilizes the fault information contained in TW at both terminals of a transmission line, so it's a protection with high reliability and high selectivity. However, because TW differential protection needs a large amount of communication, it cannot be put into practical use. This paper proposes a TW differential protection which is based on equivalent travelling wave (ETW). Fault information is not lost during the process of getting ETW, so the proposed protection has the same reliability and selectivity with traditional TW differential protection. Because only several modulus maxima are needed to be sent to the opposite terminal, the traffic is largely reduced and the protection can operate much more rapidly. Extensive simulations validate the proposed protection.

关键词： Wavelet transforms

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A combined time-and-frequency-domain model for integration of wind power generation

A combined time-and-frequency-domain model for integration o...

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2016 IEEE Innovative Smart Grid Technologies - Asia, ISGT-Asia 2016

作者： Chen, Xiaoshuang Lin, Jin Wan, Can Song, Yonghua Guo, Wanfang State Key Laboratory of Control and Simulation of Power Systems and Generation Equipment Department of Electrical Engineering Tsinghua University Beijing100084 China

ISBN: (纸本)9781509043033

Wind power generations (WPGs) are different from traditional generations for their considerable fluctuations. It is challenging to describe the status of a system with power fluctuation injections, especially when considering complicated network constraints. This paper proposes a combined time-and-frequency-domain (CTFD) model to evaluate whether the constraints will be violated under fluctuating wind power injection. The constraints of energy units and branch power flow are described in a generalized form, and are related to the power spectral density of power fluctuations. The distributions of the constraint variables are then discussed based on the CTFD model, and a chance criterion is conducted to describe the probability of the constraints being violated. Case studies show the effectiveness of the proposed model. © 2016 IEEE.

关键词： Probability distributions

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Diagnosis method for rub-impact fault of rotating machinery based on EMD and Hilbert envelop spectrum

Diagnosis method for rub-impact fault of rotating machinery ...

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

作者： Wang, Nan-Fei Jiang, Dong-Xiang Han, Te State Key Laboratory of Control and Simulation of Power System and Generation Equipments Departments of Thermal Engineering Tsinghua University Beijing100084 China

Aiming at the characteristics of the casing vibration acceleration signal of rotating machinery with rubbing fault, a diagnosis method based on EMD (empirical mode decomposition) and Hilbert envelop spectrum is put forward. When the rubbing fault occurs between the rotor and the stator, the vibration acceleration signals from the casing of the rooting machinery will present amplitude-modulated feature due to the periodical rub-impact between the rotor and the stator. However, it is relatively difficult to extract the rub-impact feature since the rub-impact signal in the process of transferring to the casing is always buried in the noise and background signals. In this paper, by means of the powerful capability of EMD and Hilbert envelop spectrum in processing nonlinear signal can accurately describe nonlinear behaviours, the fault signal is adaptively decomposed by EMD to acquire intrinsic mode functions (IMF) containing obvious feature of amplitude modulation. Then some of the sensitive IMF components are transformed by FFT and their Hilbert spectrum are analysed. The analysis results from the experimental signal show that the EMD provides an effective and adaptive method to obtain 'purified' casing vibration acceleration signal, which demonstrates the transient casing vibration more precisely and vividly, decreasing misinterpretation of the machine running condition. Therefore, the EMD approach can be applied to the single-point rubbing fault diagnosis of the rotor systems efficiently. © 2016, Society for Machinery Failure Prevention Technology. All rights reserved.

关键词： Empirical mode decomposition

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Measurement techniques on transient process of lightning striking overhead transmission lines

Measurement techniques on transient process of lightning str...

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CIGRE Session 46

作者： Xie, S.J. Li, J.M. Zhang, Y. Zeng, R. Zhuang, C.J. Wang, H. State Grid Sichuan Electric Power Research Institute State Grid Sichuan Electric Power Company China State Key Lab. of Control and Simulation of Power Systems and Generation Equipment Tsinghua University China

Obtaining the lightning strike density along an overhead transmission line and identifying the lightning strike types are the key to evaluating the lightning protection performance and proposing reasonable protection schemes of transmission lines. In addition, the waveform characteristics of lightning invasion overvoltage are the basis to establish the standard on the insulation tests of power equipment. Measuring the transient process of lightning striking overhead transmission lines is the basis to carry out the work mentioned above. In this paper, a distributed measurement method of transient current on conductors caused by lightning strikes is proposed. The measuring units are installed on the field conductors of transmission lines every 30 km to obtain less-distorted transient current waveforms. In order to enable measuring units to work in field isolated environment, a power supply coil using Faraday electric-magnetic effect and a wireless communication module is designed and developed. By far, 4776 measuring units have been installed on 597 transmission lines of China's power grid. According to measured transient current waveforms, the lightning strike point can be located using the double-end or single-end travelling wave location method, and the lightning strike type can also be identified. Moreover, a novel measurement method of lightning transient voltage based on the integrated optical electric field sensor (IOEFS) is proposed. In this method, the transient voltage waveforms are inversed from space electric field waveforms measured by IOEFSs. A series of performance tests of IOEFS have been carried out. The test results indicate that the response speed can reach several nanoseconds, and the frequency response can cover 5Hz∼100MHz which is wide enough for the measurement of the lightning transient voltage. In order to test the field measurement effect, the measurement equipment is used to measure a transient voltage when a group of capacitor voltage trans

关键词： Frequency response

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Fault diagnosis for multi-energy flows of energy internet: Framework and prospects

Fault diagnosis for multi-energy flows of energy internet: F...

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2017 IEEE Conference on Energy Internet and Energy system Integration, EI2 2017

作者： Wang, Tao Wang, Jun Fan, Zhennan Wei, Xiaoguang Zang, Tianlei Pérez-Jiménez, Mario J. Huang, Tao School of Electrical Engineering and Electronic Information Sichuan Province Key Laboratory of Power Electronics Energy-saving Technologies and Equipment Key Laboratory of Fluid and Power Machinery Ministry of Education Xihua University Chengdu China School of Electrical Engineering Southwest Jiaotong University Chengdu China State Key Laboratory of Security Control and Simulation of Power Systems and Large Scale Generation Department of Electrical Engineering Tsinghua University Beijing China Research Groupon Natural Computing Department of Computer Science and Artificial Intelligence University of Sevilla Sevilla Spain Department of Energy Politecnico di Torino Torino Italy

ISBN: (纸本)9781538614273

Energy Internet (EI) is an inevitable development trend of energy systems under the background of technology development, environmental pressure and energy transition. Multi-energy flow coupling is one of the key characteristics of the EI, which enhances the interoperability of different types of energy flows while consequently increases the probability of cascading failures. Therefore it is of great significance to study the multi-energy flow fault diagnosis of the EI to ensure its safe and stable operation as well as the continuous energy supply. This paper introduces the concept of multi-energy flow cascading fault of the EI for the first time. The energy internet framework for multi-energy flow cascading fault diagnosis is firstly proposed, and then characteristics of various energy networks in the EI are analyzed from the perspective of fault diagnosis. Finally, future research prospects are discussed. © 2017 IEEE.

关键词： Failure analysis

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Weather type partition method considering sequential features in photovoltaic forecasting

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The Journal of Engineering 2017年第13期2017卷 1259-1263页

作者： Hao Li Zongxiang Lu Ying Qiao Ningbo Wang Kun Ding State Key Lab of Control and Simulation of Power Systems and Generation Equipments Department of Electrical Engineering Tsinghua University Haidian District Beijing 100084 People's Republic of China Wind Power Technology Center Gansu Electric Power Corporation Lanzhou 730050 People's Republic of China

The prediction method based on the partition of weather types has been widely used in photovoltaic prediction. Here, the temporal characteristics of PV data is studied, the physical meaning of the sequential difference sequences is analysed, and a characteristic index system including sequential characteristics index is proposed. The weather types are partitioned based on self-organising map neural network algorithm. Case study shows that the partition method is helpful to improve the discrimination of weather types and to improve prediction accuracy.

关键词： load forecasting photovoltaic power systems prediction theory self-organising feature maps power engineering computing self-organising map neural network algorithm characteristic index system sequential difference sequence analysis PV data characteristics photovoltaic prediction method photovoltaic forecasting weather type partition method

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Modeling and analysis of secondary controlled virtual synchronous generator with dynamic droop for microgrid

Modeling and analysis of secondary controlled virtual synchr...

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

作者： Weihang Yan David Wenzhong Gao Fang Zhang Lin Cheng Shijie Yan Department of Electrical and Computer Engineering University of Denver Denver USA State Key Laboratory of Control and Simulation of Power Systems and Generation Equipment Tsinghua University Beijing China College of Information Science and Technology Northeastern University Shenyang China

ISBN: (纸本)9781538614280

In this paper, a dynamic droop mechanism is proposed to damp the synchronizing oscillation that exists in a virtual synchronous generator based distributed generator system without varying the steady-state active-power-loop droop coefficient. In order to eliminate the steady-state error introduced due to load changes or generator trips, a distributed secondary controller based on extremum seeking is employed so that microgrid frequency can be restored to nominal value. Besides, the small-signal model of virtual synchronous generator system is presented under d-q reference frame where virtual synchronous generator is deployed as a PV node. Moreover, the linearized system model of virtual synchronous generator with dynamic droop mechanism is derived and its advantage is discussed. Finally, a modified IEEE 14 bus microgrid system is established in Matlab/Simulink platform. simulation results demonstrate the validity and feasibility of the proposed method.

关键词： Mathematical model Microgrids Synchronous generators Frequency control Inverters power system stability power system dynamics

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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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Blackout Risk Analysis and control of power system Integrated with Wind Farm 28

Blackout Risk Analysis and Control of Power System Integrate...

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第28届中国控制与决策会议

作者： Zhong Yuxin Zhang Xuemin Mei Shengwei Xia Deming Wang Shuai Shi Rui Dept.of Electrical Engineering State Key Lab of Control and Simulation of Power Systems and Generation EquipmentsTsinghua University Northeast Branch of State Grid Corporation of China State Power Economic Research Institute

ISBN: (纸本)9781467397155

With the increase of wind power penetration,the characteristics of the wind farm have brought a significant impact on the security of power *** is urgent to study how to reduce the risk of cascading failures while improving the environmental *** this paper,a cascading failure model containing wind farm is proposed,which considers wind power characteristics,such as the structure of wind farm,the randomness of power of wind farm,the virtual inertia control of wind turbine,and the disconnection response of wind turbine after short-circuit *** order to identify the key factors of blackout,decision tree is used to analyze results generated from this blackout *** control is adopted to decrease the probability or effect of critical attributes that can be found in decision *** blackout risk of IEEE 30 test system integrated with wind farm is *** key factors,such as disconnection of wind turbines from the grid and certain transmission lines,are identified by decision ***,the effectiveness of the virtual inertial control of wind turbine,reactive power compensation and line construction is verified by simulation.

关键词： Wind Farm Disconnection of Wind Turbines Virtual Inertial control Blackout Risk Decision Tree

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An Evolution Model with High Proportion of Renewable Energy 35

An Evolution Model with High Proportion of Renewable Energy

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第35届中国控制会议

作者： ZHANG Weiqi ZHANG Xinyan XIA Yukai HUANG Shaowei XIAO Jinyu LU Chang MEI Shengwei College of electrical engineering Xinjiang University State Key Lab of Control and Simulation of Power Systems and Generation Equipments (Dept.of Electrical Engineering Tsinghua University) State Power Economic Research Institute

ISBN: (纸本)9781509009107

Compared with other conventional energy sources,renewable energy,which results in less pollution and has numerous resources,is a significant factor in addressing the current issues of the serious environmental pollution and the resource ***-scale renewable energy connected to the grid could lead to a the change of the morphological structure and the operation modes of energy *** current power grid evolution models did not consider the characteristics of renewable energy in the evolution *** expansion mechanism of the future transmission network with a high proportion of renewable energy is studied in this *** operation cost including renewable energy curtailment are optimized using the production simulations,where the stochastic and intermittent of wind and solar energy are *** the dual variable information is adopted to drive the grid *** expansion strategies for power grid of Zhejiang province in China are analyzed to balance the construction cost and curtailment cost of renewable energy.

关键词： Renewable energy Network evolving model Transmission planning Production simulation

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