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Experimental investigation and analysis of some common faults for wind turbine 68

Experimental investigation and analysis of some common fault...

68th Society for Machinery Failure Prevention Technology Conference: Technology Solutions for Affordable Sustainment, MFPT 2014

作者： Yang, Wenguang Li, Shaohua Jiang, Dongxiang State Key Laboratory of Control and Simulation of Power System and Generation Equipments Department of Thermal Engineering Tsinghua University Beijing100084 China

This paper focus on the fault characteristic by experimental research. A test rig is built for the direct driving stall fix-pitch horizontal axis wind turbine. 8 signals are collected by the experiment system, including wind speed, rotor rotational speed, shaft torque, the output electric power, vertical and horizontal vibration displacement of main shaft, vibration acceleration of the front bearing pedestal and the back bearing pedestal. 11 common wind turbine faults are researched by experiment. These faults are rotor mass imbalance, pneumatic asymmetry, airfoil changed, yaw fault, shaft horizontal misalignment, shaft vertical misalignment, front bearing pedestal looseness, rear bearing pedestal looseness, front bearing outer ring fault, front bearing inner ring fault, and front bearing roller fault. Several signal analysis methods, which are waveform analysis, orbit analysis, amplitude domain analysis, frequency domain analysis and envelope spectrum analysis, are adopted to extract characteristics from vibration signals. The influence on output power and vibration characteristics of these faults is presented by comparing with normal operation. The findings can be used to guide wind turbine fault diagnosis in engineering applications.

关键词： Wind

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Series-connected HV-IGBTs using active voltage control with status feedback circuit

Series-connected HV-IGBTs using active voltage control with ...

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作者： Ji, Shiqi Lu, Ting Zhao, Zhengming Yu, Hualong Yuan, Liqiang State Key Laboratory of Control and Simulation of Power System and Generation Equipment Department of Electrical Engineering Tsinghua University Beijing100084 China

ISBN: (纸本)9781479956982

The transient voltage unbalance is the major problem that limits the application of series-connected IGBTs in high voltage and high power converters. The asynchronous gate delay which causes that series-connected IGBTs do not turn-on and turn-off at the same time results in the most serious unbalanced voltage sharing. The active voltage control technique is proposed in this paper to solve the asynchronous gate delay problem. By sampling the feedback signal caused by unbalanced voltage, the microcontroller generates a time delay for gate driver to compensate the asynchronous gate delay. The most vital part of active voltage control is the status feedback circuit which is also given in detail in this paper. The function of the status feedback circuit and the effect of active voltage control are verified in a two series-connected HV-IGBTs platform in rated operation (5kV bus voltage and 600A load current). © 2014 IEEE.

关键词： Insulated gate bipolar transistors (IGBT)

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Partial discharge type recognition for transformers based on Fisher discriminant method

Partial discharge type recognition for transformers based on...

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International Conference on Estimation, Detection and Information Fusion (ICEDIF)

作者： Li Li Yongli Zhu Min Lu Liuwang Wang Yaqi Song School of Control and Computer Engineering North China Electric Power University Baoding China State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources North China Electric Power University China Zhejiang Power Dispatching & Control Center China School of Control and Computer Engineering North China Electric Power University China

Towards the problem of low rate of partial discharge (PD) recognition caused by lack of effective train samples, Fisher discriminant method is applied to improve recognition rate of PD for transformer. The discharge data produced by four PD models is collected, from which forty-four statistical characteristics are extracted. In order to solve the problem of singular matrix due to the high dimension, an effective dimension-reduced strategy is put forward. Forty-four characteristics are divided into seven low-dimensional subgroups, which become the input data for seven classifiers constructed by Fisher discriminant method. The PD type of the test samples is identified as that voted by results of seven classifiers. Results show that, in contrast to the back-propagation network method, the proposed method is more stable and possesses higher recognition rate under the condition of limited training samples, thus with good practical values.

关键词： Partial discharges Character recognition power transformer insulation Insulation Feature extraction Discharges (electric) Spectrogram

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Consistency analysis of SCADA data from field power systems

Consistency analysis of SCADA data from field power systems

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10th International Conference on Advances in power system control, Operation & Management (APSCOM 2015)

作者： Yaping Zhang Hengxu Zhang Liang Wang Guangsong Hou Key Laboratory of Power System Intelligent Dispatch and Control of the Ministry of Education School of Electrical Engineering Shandong University Jinan China Dispatch and Control Center of Shandong Electric Power Corporation Jinan China Heze Power Supply Company of State Grid Shandong Electric Power Corporation China

ISBN: (纸本)9781510830059

SCADA (Supervisory control And Data Acquisition) system is a basic infrastructure of modern power systems. SCADA data are widely used in applications such as state estimation, power flow calculation, and on-line security assessment. The accuracy of the SCADA data directly affects the implementation of power system automatic control. In practice, the error of the SCADA data may deviate from its factory precision due to the influence of the equipment aging, data transmission and so on. To quantitatively evaluate the validity of the SCADA data, a consistency index is defined in this paper. Some SCADA data from several substations of a power gird is checked with the consistency index to reveal its reliability.

关键词： consistency power systems SCADA error analysis

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Regional Pole Placement of a Markovian jump Model for Wind Turbine Generator system

Regional Pole Placement of a Markovian jump Model for Wind T...

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IEEE Annual Conference on Decision and control

作者： Zhongwei Lin Jizhen Liu Yuguang Niu State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources School of Control and Computer Engineering North China Electric Power University Beijing 102206 P. R. China

ISBN: (纸本)9781479978878

This paper discusses the regional pole placement problem for Markovian jump system, and the corresponding application on wind turbine generator system (WTGS). Through sampling the low-frequency wind speed datas into separate intervals, the dynamic process of WTGS can be modelled into Markovian jump system. The traditional operating points of wind turbine are divided into separate subregions correspondingly, where the model parameters and the control mode can be fixed in each mode. However, the control designed for each operating subregion can not guarantee the whole dynamic response performance of WTGS, which is caused by the stochastic switchings between different system modes. Hence, the pole placement problem is discussed for linear Markovian jump systems, and applied on improving the dynamics response of WTGS.

关键词： pole assignment Wind Generators jump control modes model parameters Wind Energy Conversion systems

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Double-Objective Optimal control for Non-Gaussian systems: An Example Study on Analytical vs Numerical Solutions

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IFAC-PapersOnLine 2015年第8期48卷 924-929页

作者： Mifeng Ren Jianhua Zhang Hong Wang Min Huang College of Information Engineering Taiyuan University of Technology Taiyuan 030024 China State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources North China Electric Power University Beijing 102206 China Control System Centre School of Electrical and Electronics Engineering The University of Manchester M60 1QD UK China State Key Laboratory of Synthetical Automation for Process Industry Northeastern University Shenyang 110819 China

Minimum entropy control has been proven to be an effective method in control of non-Gaussian stochastic systems. In this case, the entropy is proposed as a generalization of the variance measure to characterize the randomness of the process. Minimum entropy corresponds to small uncertainty (or derivation), but it cannot guarantee the tracking error approaching to zero. Therefore, mean square error also should be added in the criterion. In this paper, by using a simple example, the method of generating a representative approximation of the Pareto optimal control set is investigated in both analytical and numerical ways. And simulation results show the feasibility of the proposed double-objective optimal control method.

关键词： Double-objective optimal control non-Gaussian stochastic systems Renyi's entropy e - constrained method estimation of distribution algorithm

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DC fault analysis of VSC-HVDC and DC cable protection principle

DC fault analysis of VSC-HVDC and DC cable protection princi...

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IEEE PES Asia-Pacific power and Energy Engineering Conference (APPEEC)

作者： Pu Zhao Qing Chen Luhua Xing Key Laboratory of Power System Intelligent Dispatch and Control(Shandong University) Ministry of Education Jinan China Shandong University Jinan Shandong CN State Grid Shandong Electric Power Research Institute Jinan China

ISBN: (纸本)9781467381338

Voltage Source Converter (VSC) based HVDC (VSC- HVDC) transmission technology as a kind of new dc transmission, is attracting more and more research. VSCs are susceptible to cable short-circuit fault and ground fault. This paper focuses on the transient characteristics of electrical quantities in a two terminal VSC-HVDC system after the occurrence of short-circuit fault and ground fault. Equivalent circuits and equations are given to calculate the voltage and over-current in cable. simulations are undertaken in PSCAD to verify the calculation results, and different fault points and fault resistances are considered. Due to the behaviors of DC voltage and cable over-current in faulty cable and non-faulty cable after the ground fault, a DC cable protection principle was proposed to determine the faulty cable and to decide fault within or outside the protected area.

关键词： Circuit faults power conversion power cables Capacitors Equivalent circuits Transient analysis

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The application of TCSC for damping inter-area oscillations

The application of TCSC for damping inter-area oscillations

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IEEE PES Asia-Pacific power and Energy Engineering Conference (APPEEC)

作者： Jingli Liu Lei Ding Deyu Cai Zhiming Song Key Laboratory of Power System Intelligent Dispatch and Control Ministry of Education Shandong University Jinan China Shanghai Electric Power Corporation Ltd Shanghai China State Grid of China Technology College Jinan China

ISBN: (纸本)9781467381338

This paper presents a wide area control scheme using TCSC for damping inter-area oscillation. In general, TCSC are facilitated over long transmission lines to enhance the power transmission capability. As the inter-area oscillations are associated with heavy power transfer over long transmission corridors, the small signal/oscillatory stability can be improved if an additional damping control can be integrated into the control scheme of TCSC. The paper presents the classic and additional damping control scheme of TCSC. The typical two-area power system and control scheme that are built using `DIgSILENT powerFactory', and the damping control is tested through the classic modal analysis and simulations in time domain.

关键词： power capacitors Thyristors Damping Oscillators Economic indicators power system stability system performance

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Coordinated optimization for controlling short circuit current and multi-infeed DC interaction

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Journal of Modern power systems and Clean Energy 2014年第4期2卷 374-384页

作者： Dong YANG Kang ZHAO Yutian LIU State Grid Shandong Electric Power Research Institute Jinan 250002China Key Laboratory of Power System Intelligent Dispatch and Control of Ministry of Education Shandong UniversityJinan 250061China

Due to increased penetration of renewable energies,DC links and other emerging technologies,power system operation and planning have to cope with various uncertainties and *** order to solve the problems of exceeding short circuit current and multi-infeed DC interaction,a coordinated optimization method is presented in this ***,a branch selection strategy is proposed by analyzing the sensitivity relationship between current limiting measures and the impedance ***,the impact of network structure changes on the multi-infeed DC system is *** the coordinated optimization model is established,which considers the cost and effect of current limiting measures,the tightness of network structure and the voltage support capability of AC system to multiple ***,the non-dominated sorting genetic algorithm II combining with the branch selection strategy,is used to find the Pareto optimal *** studies on a planning power system demonstrated the feasibility and speediness of this method.

关键词： Operation and planning Multiple DC infeed Short circuit current Sensitivity analysis Multi-objective optimization

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Extended kalman filter-based sensor fault diagnosis in heat exchangers

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ICIC Express Letters, Part B: Applications 2015年第5期6卷 1397-1404页

作者： Zhang, Jianhua Chen, Yannan Zhang, Luyao Xiong, Jing Hou, Guolian State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources No. 2 Beinong Road Huilongguan Beijing China School of Control and Computer Engineering North China Electric Power University No. 2 Beinong Road Huilongguan Beijing China

The dynamics of heat exchanger is complex in terms of nonlinearity, timevarying, uncertainty, so extended Kalman filter (EKF) is utilized to diagnose the instrument faults existing in heat exchangers. EKF is employed to generate residuals for detecting sensor faults, and the residuals are then evaluated to isolate the location of faults using decision functions. simulation results testify EKF based fault diagnosis method is suitable to identify sensor faults in heat exchangers. © 2015.

关键词： Failure analysis

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