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2012 3rd Annual IEEE Prognostics and System Health Management Conference, PHM-2012

作者： Xu, Hongzhi Jiang, Dongxiang Liang, Lei State Key Laboratory of Control and Simulation of Power System and Generation Equipment Department of Thermal Engineering Tsinghua University Beijing 100084 China

Aircraft engine is an important component of the airplane, which lifespan and reliability have directly influence to flight safety. Vibration analysis is an effective fault diagnosis method for airplane's mechanical construction fault. Several typical vibration faults have drawn from the vibration analysis on the basis of fault mechanism in aircraft engine, and the standard vibration fault-symptom (Fuzzy Membership) relationship table have constructed based on Fuzzy Mathematic theory in this paper. Sample data are simulated on the basis of this table. Sequential Minimal Optimization (SMO) is a fast algorithm for training Support Vector Machines (SVM). The simulated result showed a great improvement on computation efficiency by selecting double threshold parameter for SMO algorithm than single threshold. In order to examine the algorithm's effect applying in the aircraft engine fault diagnosis, Radial Basis Function (RBF) Neural Network, C4.5 Decision Tree, SVM (chunking), Platt's SMO and Improved SMO algorithm are applied to the training data and test data. It is shown that the Improved SMO algorithm displayed superior comprehensive performance. Finally, the vibration fault feature is reduced based on Fuzzy-Rough Sets theory. The research shows that the Improved SMO algorithm is quicker than other algorithm in aircraft engine fault diagnosis with the reduced feature attributes, and its accuracy is high. © 2012 IEEE.

关键词： Support vector machines

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A Two-level Energy Storage System for Wind Energy systems

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Procedia Environmental Sciences 2012年 12卷 130-136页

作者： Xi Xiao Hu Yi Qing Kang Jinfeng Nie State Key Laboratory of Control and Simulation of Power Systems and Generation Equipment singhua University Beijing China

Wind power outputs fluctuate with the changing of wind speed. The use of energy storage equipment is considered a reasonable solution to suppress wind power fluctuations. An energy storage mode may have its disadvantages over the others, for example, capacity limits, dynamic response, higher prices or shorter lifetime. Moreover, wind power fluctuations are present at different frequencies, to demand the energy storage to offer power support in different time ranges. To improve the performance, in this paper, a combined energy storage mode is discussed to meet the short-term and long-term energy storage requirement for wind power. Short-term energy storage is designed to meet the fast-changing power, using such as super capacitors. Long-term energy is designed to meet the large-scale capacity requirement using Li-ion battery or Vanadium Redox Battery (VRB). By analyzing the actual data of wind power outputs, the capacities of the two kinds of energy storage means are given as an example of the method.

关键词： Wind power energy storage capacity designing

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Research on shielding failure of UHVDC based on leader progression model

Research on shielding failure of UHVDC based on leader progr...

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2012 31st International Conference on Lightning Protection, ICLP 2012

作者： Geng, Yinan Zhuang, Chijie Institute of Nuclear and New Energy Technology Tsinghua University Beijing China State Key Lab of Control and Simulation of Power Systems and Generation Equipment Tsinghua University Beijing China

ISBN: (纸本)9781467318976

Shielding failure is one of key problems of UHV transmission lines. Considering the high operating voltage and high tower of UHV transmission lines, the inception criterion of upward leader is proposed in this paper. The process of shielding failure is simulated by the method based on leader progression model and shielding failure rate is calculated. This method is verified by comparing the calculation results with the operated data of UHV transmission lines in Japan. The shielding failure characteristics of UHVDC transmission lines in China under different terrain conditions are researched. © 2012 IEEE.

关键词： Electric lines

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A cooperative game theory based multi-objective reactive voltage optimization model and its solution

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Dianli Xitong Zidonghua/Automation of Electric power systems 2012年第18期36卷 116-121+133页

作者： Zhang, Mingye Guo, Qinglai Sun, Hongbin Zhang, Boming Wu, Wenchuan Wang, Bin State Key Laboratory of Control and Simulation of Power Systems and Generation Equipments Tsinghua University Beijing 100084 China

To coordinately consider the economy and security of the system during reactive voltage control, a multi-objective reactive power optimization model is proposed. Apart from the conventional economic objective, the new model has the system static security added to the multi-objective to seek their optimization simultaneously. And the solution for the model is proposed based on the cooperative game theory. As two players of the game, the economy side and the security side decide on their game strategies alternately until equilibrium is attained. Tests on a 2-bus system and IEEE 9-bus system demonstrate the feasibility and advantages of the model along with the proposed method. © 2012 state Grid Electric power Research Institute Press.

关键词： Multiobjective optimization

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Self-precharge of floating capacitors in a five-level ANPC inverter

Self-precharge of floating capacitors in a five-level ANPC i...

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2012 IEEE 7th International power Electronics and Motion control Conference - ECCE Asia, IPEMC 2012

作者： Wang, Kui Li, Yongdong Zheng, Zedong Xu, Lie Ma, Hongwei State Key Laboratory of Control and Simulation of Power System and Generation Equipments Department of Electrical Engineering Tsinghua University Beijing China

ISBN: (纸本)9781457720864

Five-level active neutral-point-clamped (ANPC) converter is a newly emerging topology which can overcome the drawbacks of traditional neutral-point-clamped and flying-capacitor multilevel converters. During the start-up of the converter, it must be ensured that the switches and capacitors cannot be overvoltage and overcurrent due to the uncharged floating capacitors. In this paper, a floating capacitor self-precharge method is proposed which, by transferring the circuit into a booster, charges the floating capacitors to the reference voltage with a very small average load current. simulation and experimental results are presented to verify the validity of this method. © 2012 IEEE.

关键词： power converters

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Principle and Model for Regional Allocation of Carbon Emission from Electricity Sector

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Electricity 2012年第4期23卷 52-53页

作者： Li Baowei Hu Zechun Song Yonghua Wang Guanghui State Key Lab of Control and Simulation of Power Systems and Generation Equipment Dept. of Electrical Engineering Tsinghua University

The paper “Principle and Model for Regional Allocation of Carbon Emission from Electricity Sector” is focused on the hot issue of carbon allocation problem,while the research scope is restricted to electricity *** authors propose a fair allocation principle considering the social contribution and environmental cost of electricity *** to the allocation principle,a novel model and concept of carbon flow tracing is presented to satisfy the requirements based on electricity flow tracing methodology,which traces the sources of regional electricity imports to determine the carbon allocation reasonably.

关键词：分配原则电力行业碳排放跟踪方法分配问题电力部门电力供应碳分配

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Battery energy storage system load shifting control based on real time load forecast and dynamic programming

Battery energy storage system load shifting control based on...

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2012 IEEE International Conference on Automation Science and Engineering: Green Automation Toward a Sustainable Society, CASE 2012

作者： Bao, Guannan Lu, Chao Yuan, Zhichang Lu, Zhigang State Key Laboratory of Control and Simulation of Power System and Generation Equipments Tsinghua University Beijing 100084 China Electric Power Research Institute China Southern Power Grid Guangzhou 510080 China

ISBN: (纸本)9781467304283

Battery energy storage system (BESS) is one of the key technologies for smart grid and load shifting is one of the fundamental functions of BESS. BESS load shifting performance is determined by the availability of accurate load curves and optimization approaches. In this paper, a real-time control strategy based on load forecast and dynamic programming methods is presented. The predicted load curve is updated on-line through regress forecasting. The proposed optimization model is solved by using dynamic programming technique. The objective is peak shaving and prolonging the battery lifetime, and the constraints considered include battery state-of-charge (SOC), cycling times per day, converter capacity and step power. The above control strategy was successfully applied to the 5MW*4hour lithium-Ion BESS demonstration project in Biling substation, China Southern power Grid. The simulation results based on the actual load data of Biling substation demonstrate the effectiveness. © 2012 IEEE.

关键词： Dynamic programming

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Soft-switching analysis of a resonant capacitor current feedback self-oscillating inverter

Soft-switching analysis of a resonant capacitor current feed...

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2012 IEEE 7th International power Electronics and Motion control Conference - ECCE Asia, IPEMC 2012

作者： Shao, Mingsong Huang, Songling Zhao, Wei Wang, Changquan State Key Laboratory of Control and Simulation of Power System and Generation Equipment Department of Electrical Engineering Tsinghua University Beijing China Lighting Research Center Century Zhuoke Energy and Technology Co. LTD Beijing China

ISBN: (纸本)9781457720864

In this paper, we examine a resonant capacitor current feedback (RCCF) self-oscillating resonant inverter from nonlinear point of view. By adopting a four-stage equivalent model, we derive the soft-switching dead time from time-domain for the series resonant capacitor linked parallel load circuit. Importantly, we propose a nonlinear model for the current feedback and gate-drive circuit. Based on analyzing the switching transition interval of this model, the determination of feedback parameters is inferred with given input power and resonant elements. Experimental results have been obtained for a RCCF self-oscillating inverter operating at 3 MHz and 300 V bus voltage. © 2012 IEEE.

关键词： Feedback

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The large-size low-stray-parameter planar bus bar for high power IGBT-based inverters

The large-size low-stray-parameter planar bus bar for high p...

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International Conference on Electrical Machines and systems (ICEMS)

作者： Liqiang Yuan Hualong Yu Xuesong Wang Zhengming Zhao Ting Lu State Key Laboratory of Control and Simulation of Power System and Generation Equipment Tsinghua University Beijing China

The large-size planar DC bus bar is widely used in high power converters, whose stray parameters are significantly affected the converter reliability and performance. Taking the example of an actual 315kW/400V inverter, the design, simulation and analysis for its bus bar stray parameters is described in detailed. Being different from the conventional method that considers the bus bar conductor as an entirety, an improved method is proposed in this paper, which separates the bus bar into several segments and evaluates the influence of stray parameters in each segment to the power semiconductor devices respectively. Therefore, this improved method can provide support for the more accurate and effective design and optimization of bus bar. In addition, two different structure of bus bar are implemented in the actual inverter, the comparison and analysis of experiment results for both structures proves the validity of the proposed method.

关键词： Inverters Insulated gate bipolar transistors Equivalent circuits Integrated circuit modeling Inductance Conductors Snubbers

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A schedule power flow auto generating technology in day-ahead security validation

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Dianli Xitong Zidonghua/Automation of Electric power systems 2012年第20期36卷 68-73页

作者： Lin, Yi Sun, Hongbin Wu, Wenchuan Yu, Jun Zhang, Boming State Key Laboratory of Control and Simulation of Power Systems and Generation Equipments Tsinghua University Beijing 100084 China National Electric Power Dispatching and Communication Center Beijing 100031 China

Formulation of day-ahead operation schedule for large-scale power grid requires security validation, including static security, dynamic and transient stability. It is an important and basic task for day-ahead security validation to generate an AC power flow that satisfies the demand of the schedule. A new method of generating the day-ahead schedule power flow is proposed, which consists in dividing the problem into two subproblems-the active subproblem and the reactive subproblem. The inconsistency of various kinds of schedule data is coordinated by solving the active subproblem, while a rational voltage distribution is achieved by solving the reactive subproblem. Both of the two problems are formulated as optimization models with constraints satisfied and are solved with an interior point algorithm. Numerical test results on the testing system and real power systems show that the method is capable of providing rational day-ahead schedule power flow. © 2012 state Grid Electric power Research Institute Press.

关键词： Numerical methods

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