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Weather type partition method considering sequential features in photovoltaic forecasting

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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Stability Analysis and Braking system Design of Icebreaker Propulsion system Based on 3L-NPC Inverter

Stability Analysis and Braking System Design of Icebreaker P...

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Smart power & Internet Energy systems (SPIES), International Conference on

作者： Nianzhou Liu Nan Fu Pengfei Xie Wenfeng Long Kui Wang Yongdong Li Science and Technology on Ship Integrated Power System Technology Laboratory Wuhan Institute of Marine Electrical Propulsion Wuhan China State Key Lab of Control and Simulation of Power System and Generation Equipment Tsinghua University Beijing China

The icebreaker is important in the polar scientific investigation and resource exploration. There will be pulse and periodic load during the continuous icebreaking process, which may affect the propulsion system of the icebreaker. This paper mainly analyzes the effect of the impact load on the three-level neutral point clamped (3L-NPC) inverter with diode front-end, and demonstrates the relationship between the impact load and the feedback energy. Moreover, the choice of the resistance of the braking resistor is briefly discussed. The simulation results are given at last, which verify the rationality and correctness of the theoretical analysis.

关键词： Resistors Resistance simulation Energy Propulsion Inverters Stability analysis

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Optimization of LNG Terminal Reserve Planning for Combined Gas and Electricity system

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Energy Procedia 2017年 105卷 3332-3338页

作者： Gang Chen Qinzhe Liu En Lu Qixin Chen Guangdong Provincial Electric Power Dispatching Center Yuexiu District Guangzhou Guangdong Province 510600 China State Key Lab of Control and Simulation of Power System and Generation Equipment (Department Electrical Engineering Tsinghua University) Haidian District Beijing 100084 China

Considering the effect of LNG supplying risk on the combined gas and electricity system's operation under the multi-gas-source supply background, the optimization planning model of the combined system's LNG reserve is developed in this paper. The optimization objective of this model is minimizing the annual cost of combined system, considering operation simulation of several typical scenarios along 52 weeks in a whole year and the annualized investment of LNG tanks. The operation objective of each scenario is determined by LNG's arrival and the operation mode of LNG terminals. A test system of IEEE-39 test system and Belgian 20-node system is formulated. The optimal LNG reserve of the test system is solved, and the effect of load level and operation mode on the reserve planning is also analyzed.

关键词： Combined gas and electricity system LNG supply Reserve planning Natural gas system Operation mode

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Research on Lithium-ion Battery Safety Risk Assessment Based on Measured Information

Research on Lithium-ion Battery Safety Risk Assessment Based...

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Sustainable power and Energy Conference (iSPEC)

作者： Xuyan Zhou Lin Cheng Yuxiang Wan Ning Qi Liting Tian Feng You State Key Laboratory of Control and Simulation of Power Systems and Generation Equipments Tsinghua University Beijing China Energy Storage System Business Unite Tianjin Lishen Battery Joint-Stock Co. Ltd. Tianjin China

ISBN: (数字)9781728191645

ISBN: (纸本)9781728191652

Lithium-ion batteries have the advantages of high energy density, fast power response, recyclab.lity, and convenient to movement, which are unsurpassed by other energy storage systems. However, safety issues such as thermal runaway of lithium-ion batteries have become the main bottlenecks restricting the development of their extensive applications. In practical applications, the demand for battery energy storage scale and specific energy continues to increase, and the contradiction between battery high safety and battery safety has become increasingly prominent. This paper proposes a lithium-ion battery safety risk assessment method based on online information. Effective predictions are essiential to avoid irreversible damage to the battery and ensure the safe operation of the battery energy storage system before a failure occurs. This paper is expected to provide novel risk assessment method and research idea for the development and design of high-safety battery systems.

关键词： Lithium-ion batteries Temperature measurement Voltage measurement Thermal management Battery charge measurement Safety Risk management

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Vibration and Noise Emitted by Dry-type Air-core Reactors Under Sine-wave Current Excitation

Vibration and Noise Emitted by Dry-type Air-core Reactors Un...

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International Conference on Electrical Machines and systems (ICEMS)

作者： Jingsong Li Baojun Qu Keping Yu State Key Laboratory of Control and Simulation of Power System and Generation Equipments Tsinghua University Beijing China State Key Laboratory of Reliability and Intelligence of Electrical Equipment Hebei University of Technology Tianjin China Global Information and Telecommunication Institute Waseda University Tokyo Japan

ISBN: (纸本)9781728133997

According to magneto-mechanical strong coupled effect, structure mode is discussed by engaging finite element (FE) method and both natural frequency and modal shape for a dry-type air-core reactor (DAR) are obtained in this paper. On the basis of harmonic response analysis, electromagnetic forces under sine-wave current excitation are mapped with the structure mesh, the vibration spectrums are gained and the consequences represent that the whole structure vibration predominates in the axial direction, with less radial vibration. Referring to the test standard of reactor noise, the rules of emitted noise of the DAR are measured and comparatively analyzed at power frequency and chosen other frequencies match the sample resonant frequency and the methods of active vibration and noise reduction are put forward. Finally, the low acoustic noise emission of a prototype DAR is verified by simulation and measurement.

关键词： Vibrations Acoustic measurements Noise measurement Acoustic noise Magnetomechanical effects Resonant frequency Harmonic analysis

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Multiple-Stage Inter-temporal Flexibility for Planning: A Non-sequential Probabilistic Production simulation Approach

Multiple-Stage Inter-temporal Flexibility for Planning: A No...

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power, Energy and Electrical Engineering (CPEEE), International Conference on

作者： Ying Qiao Haibo Li Jiheng Jiang Guobin Fu State Key Lab of Control and Simulation of Power Systems and Generation Equipments Tsinghua University Beijing China Sichuan Energy Internet Research Institute Tsinghua University Chengdu China State Grid Qinghai Provincial Electric Power Company Xining China

ISBN: (数字)9781728177175

ISBN: (纸本)9781728177182

High wind energy curtailment during winter and early spring in north China has drawn widespread concern in recent years, which, at source, results from the shortage of power system flexibility. Therefore, power system needs to consider the flexibility in planning stage. However, current flexibility metric is difficult to calculate and be applied in to the optimal planning. A non-sequential production simulation model with only input data of the cumulative probability function and/or probability density function of heat demand, electricity demand, and wind power is proposed, which is used to obtain the probability distribution of the production for generators according to least cost principle. Then the flexibility metric can be easily calculated based on the production results. simulations were performed based on the actual data of a large wind power zone in north China. Multiple flexibility metric was evaluated and compared with the wind power curtailment, which shows the strong correlation between them. Finally, the impact of flexible resources on the flexibility metric was analyzed.

关键词： Measurement Production Wind power generation Data models Planning Space heating Resistance heating

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state of the art of hybrid excitation permanent magnet synchronous machines

State of the art of hybrid excitation permanent magnet synch...

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2010 International Conference on Electrical Machines and systems, ICEMS2010

作者： Wang, Shanming Xia, Yonghong Wang, Xiangheng Su, Pengsheng Huang, Shaogang Zhang, Anming State Key Laboratory of Control and Simulation of Power System and Generation Equipments Department of Electrical Engineering Tsinghua University Beijing 100084 China Department of Electrical and Automatic Engineering Nanchang University Nanchang Jiangxi 330031 China Military Deputy Department Dalian 426 Factory No.1 Yanhai Jie Xigang Qu Dalian Liaoning 116005 China

The hybrid excitation permanent magnet machine (HEPMM) combines two kinds of excitation: permanent magnet (PM) and electrical excitation, so it possesses the advantages of PM machines and overcomes the incapability of regulating the excitation field. By now many HEPMM schemes have been presented. In this paper the operation principle, structure, advantages and disadvantages of these HEPMMs have been reviewed and compared in detail. These HEPMMs are classified into three types by new classification method - placement of PM and iron poles. At last novel harmonic excitation HEPMM is proposed and discussed.

关键词： Iron Magnetic fields Windings Stator cores Rotors Stator windings Magnetic circuits

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Solving of interval DC power flow using interval Hull algorithm with preconditioning

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Dianli Xitong Zidonghua/Automation of Electric power systems 2014年第3期38卷 130-136页

作者： Ding, Tao Guo, Qinglai Bo, Rui Gu, Wei Sun, Hongbin Zhang, Boming Department of Electrical Engineering Tsinghua University Beijing 100084 China State Key Laboratory of Control and Simulation of Power Systems and Generation Equipments Tsinghua University Beijing 100084 China Midwest Independent Transmission System Operator Inc. Saint Paul 55108 United States School of Electrical Engineering Southeast University Nanjing 210096 China

With intermittent sources integrated into the power grid, power flows of the power grid are getting stochastic. Considering the uncertainty problem of DC power flow in the high voltage transmission system, this paper recommends an interval Hull algorithm with preconditioning to solve the interval DC power flow. Firstly, the diagonal dominant interval coefficient matrix is formed by preconditioning, then the H-matrix is obtained using the interval Hull algorithm. Different approximation methods are employed for the comparison matrix of H-matrix to improve precision. And the upper and lower bound of the distribution of interval DC power flow is obtained with the iterative method. The interval Hull algorithm and Monte Carlo algorithm are compared in the 9-bus test system, the result of which shows that the uncertainty in grid parameters is the main cause of errors. Furthermore, the Hull algorithm with preconditioning, the interval Hull method, the Krawczyk operator iteration method and the Gauss elimination method are compared in terms of accuracy and computing time on an IEEE 57-bus and an IEEE 118-bus test system, respectively. It is shown that the Hull method with preconditioning has the best accuracy, and the time complexity is far lower than that of the Monte Carlo algorithm. © 2014 state Grid Electric power Research Institute Press.

关键词： Iterative methods

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Ancillary service for frequency regulation based on multi-energy virtual power plant aggregating factory load

Ancillary service for frequency regulation based on multi-en...

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The 11th IET International Conference on Advances in power system control, Operation and Management (APSCOM 2018)

作者： Jiazhen Wang Xinwei Shen Yinliang Xu Qinglai Guo Hongbin Sun Yanbo Chen Shenzhen Environmental Science and New Energy Technology Engineering Laboratory Tsinghua-Berkeley Shenzhen Insitute Tsinghua University Shenzhen China State Key Lab of Control and Simulation of Power System and Generation Equipments Department of Electrical Engineering Tsinghua University Beijing China State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources North China Electric Power University

ISBN: (数字)9781839530043

With the increasing proportion of renewable energy generation into the power grid, more challenges are coming to the safe and stable operation of the power system. In order to keep the balance in energy market, system operator has to purchase much service in ancillary service market to guarantee the stable operation of the power transmission. Virtual power plant (VPP) has been extensively studied as a concept that aggregates multiple resource forms to serve the electricity market. Meanwhile, with the development of Energy Internet (EI) Error! Reference source not found., more attention has been focused on the optimization and operation of Integrated Energy system (IES), therefore, the introduction and exploration of Multi-energy Virtual power Plant (MVPP) provide possibilities for IES to participate in the Electricity Market and Ancillary Services Market. This paper extracts the flexible electric and heat load in the industrial production process, combining the CHP units and Electric Boiler (EB), which are main heat energy supply devices as well as Energy Storage system (ESS) as a MVPP to provide Frequency Regulation (FR) service to the Auxiliary Service Market. Model Predictive control (MPC) method is applied to control the industrial load, the operation of CHP, EB and ESS are gonging to follow the AGC signal issued by the FR market effectively while avoiding impacts on the production process of the factory. Finally, case study validates the effectiveness of the model.

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ANALYSIS OF FATIGUE LIFE LOSS OF DRIVETRAIN OF DOUBLY-FED WIND TURBINES UNDER SHORT-CIRCUIT FAULT OF power GRID

ANALYSIS OF FATIGUE LIFE LOSS OF DRIVETRAIN OF DOUBLY-FED WI...

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International Conference on Renewable power generation

作者： Qiu Shilong Li Hui Gong Lijiao Wang Bin Chai Zhaoseng Wu You Department of Mechanical and Electrical Engineering Shihezi University Shihezi China State Key Laboratory of Power Drivetrain Equipment and System Security Chongqing University Chongqing China State Key Lab of Control and Simulation of Power Systems and Generation Equipments (Department of Electrical Engineering) Tsinghua University Haidian District Beijing China State Key Laboratory of Power Drivetrain Equipment and System Security Chongqing University Chongqing China

ISBN: (数字)9781839531248

ISBN: (纸本)9781839531255

The shafting drivetrain of the doubly fed wind turbine is the part with the highest failure rate. The electromagnetic torque fluctuation caused by the grid fault easily results in the torsional vibration fatigue loss of the shaft. Accordingly, the influences of drivetrain fatigue life loss under different grid faults require investigation. Firstly, the four-mass model of the drivetrain is constructed on the basis of MATlab.Simulink. Secondly, the electromagnetic torque response under short-circuit fault of the grid is obtained via model simulation. Finally, the effects of different types of grid faults on the fatigue life of the drivetrain are analysed through Mlife. Results show that the electromagnetic torque fluctuation load generated by grid fault has no apparent influence on the fatigue life of the drivetrain in the short term, but the cumulative effect of short-term damage will aggravate the fatigue life loss of the drivetrain and increase the failure risk of the component. The electromagnetic torque generated by the three-phase symmetrical short-circuit is the most violent and has the maximum effect on the fatigue life of the drivetrain.

关键词： WIND TURBINE SHORT-CIRCUIT FAULT TORSIONAL VIBRATION FATIGUE LIFE DRIVETRAIN

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