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2nd IET Renewable power generation Conference (RPG 2013)

作者： G. Feng Y. Xu Y. Chen H. Gao L. Chen Tsinghua University Beijing Beijing CN State Key Lab of Control and Simulation of Power Systems and Generation Equipments Dept. of Electrical Engineering Tsinghua University Beijing 100084 China

ISBN: (纸本)9781629936017

Due to the power electronic devices in doubly fed induction generators (DFIG), it is very time consuming to simulate the electromagnetic transients of DFIG using its detailed model. Thus it is necessary to have appropriately simplified model of DFIG that maintains desirable accuracy. In this paper, the piecewise averaged model of PWM converters is introduced and applied to the modelling of DFIG. The proposed model divides the simulation time interval into switching periods and recalculates the averaged state equations of PWM converters in each switching cycle. In addition, a predictorcorrector based EMTP algorithm is designed to iteratively solve the model. Instead of treating switching events at the time points when they happen, the new algorithm solves all the switching instants in a switching cycle at the same time, which avoids frequency modification of the system conductance matrix and speeds up EMT simulations of DFIG. simulation results of a single-machine infinity bus system with a DFIG show that the proposed model and algorithm can achieve satisfactory accuracy and efficiency.

关键词： Average modelling Doubly fed induction generators Electromagnetic transient simulation

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Research on Peak Load Regulation Capacity Planning for Long-term Market

Research on Peak Load Regulation Capacity Planning for Long-...

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2017 International Electrical and Energy Conference (CIEEC 2017)

作者： Jiheng Jiang Ying Qiao Zongxiang Lu Ningbo Wang Jin Li Kun Ding State Key Lab of Control and Simulation of Power Systems and Generation Equipments Dept.of Electrical Engineering Tsinghua University Key Laboratory of Wind Power Integration Operation and Control of Gansu Province Gansu Electric Power Corporation Wind Power Technology Center

Insufficient power capacity for peak load regulation has caused loss of wind power accommodation in China.A regulation capacity market is under consideration to encourage more peak regulation service,thus how much the market would be is important for each participant.A new peak-load regulation capacity planning method is proposed for long-term market based on the wind power curtailment evaluation model using probabilistic production *** method is suitable for the situation in the planning stage without the knowledge of detailed sequences of load and renewable power,and includes modeling of two peak load regulation measures,increasing the adjustable capacity and to shift some long-lasting units to on/off cycling units.A typical area in China is studied in the paper to evaluate the actual effects of different measures.

关键词： adjustable capacity capacity planning peak load regulation probabilistic production simulation

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Evaluation of Prediction Choice in Economic Dispatch with Uncertainty

Evaluation of Prediction Choice in Economic Dispatch with Un...

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2017 International Electrical and Energy Conference (CIEEC 2017)

作者： Fan Zhang Ying Qiao Zongxiang Lu Ningbo Wang Jin Li Kun Ding State Key Lab of Control and Simulation of Power Systems and Generation Equipments Dept.of Electrical EngineeringTsinghua University Key Laboratory of Wind Power Integration Operation and Control of Gansu Province Gansu Electric Power Corporation Wind Power Technology Center

The unavoidable wind power forecast error results in the pervasive uncertainty in power system economic *** order to solve optimization problem such as economic dispatch with random variables,the commonest and simplest method is using a deterministic value to replace this random *** kinds of predictions are used such as maximumlikelihood approximation,expectation and *** study analyses the effect of these prediction choices on uncertainty of power system via comparing their statistical *** is shown that when the wind power output is very volatile,the quality of these prediction choices is not ***,a simplified three-unit thermal system and a tenunit system are studied for illustrating the consequence of statistical inconsistency.

关键词： Economic Dispatch expectation maximumlikelihood prediction uncertainty wind power forecast error

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Interrupter Pressure Measurement of a 252 kV SF6 Circuit Breaker

Interrupter Pressure Measurement of a 252 kV SF6 Circuit Bre...

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2011 1st International Conference on Electric power Equipment- Switching Technology(第一届电力设备开断技术国际会议 ICEPE)

作者： Weidong Liu Yonggang Guan Wenyi Li Junhui Wu State Key Lab of Control and Simulation of Power Systems and Generation Equipments (Dept.of Electric Henan Pinggao Electric Co. LTD. Pingdingshan 467001 Henan Province China

ISBN: (纸本)9781457712739

The transient pressure process, which determined the gas blasting in the interrupter of SF6 circuit breaker, have attracted the attention of designer and developer for long time. In this investigation, a onload SF6 interrupter pressure measurement method was established with piezoresistive pressure transducer and insulating-tube. The pressures in the puffer cylinder, at the upstream, throat and downstream of nozzle have been measured. The difference of gas blowing characteristics between N2 and SF6 has been pointed out. The insulating-tube can effectively protect the pressure transducer from the high voltage and high temperature during on-load interrupting. It was found that the arc process can cause high frequency oscillations to superimpose upon the pressure waveforms during on-load interrupting.

关键词： interrupters Pressure Transducers Sulfur Hexafluoride Pressure measurement High Voltage Designers nozzles pressure process

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Effect of frequency on electrical tree characteristics in silicone rubber

Effect of frequency on electrical tree characteristics in si...

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International Conference on Properties and Applications of Properties and Applications of Dielectric Materials

作者： Qiong Nie Yuanxiang Zhou Zhengzheng Chen Haihang Chen State Key Lab of Control and Simulation of Power Systems and Generation Equipments Dept of Electrical Engineering Tsinghua University Beijing 100084 China Dept of Electrical Engineering Zhengzhou University 450001 China

As an advanced internal insulating material, silicone rubber has been widely used in extra high voltage prefabricated cable accessories. However, few studies were focused on the influence of frequency on the electrical tree characteristics and the damage mechanism of such insulation is still unknown. In this paper, the characteristics of electrical tree in silicone rubber under AC voltage of different frequency ranging from 50 Hz to 130 kHz were studied. The tree initiation voltage was measured at room-temperature and the processes of electrical tree were observed via a digital micro-observing system. From the experiments, it was found that the electrical tree in silicone rubber is greatly affected by the frequency of applied voltage. With the increase of frequency, tree initiation voltage of silicone rubber decreases. And the frequency can be separated into four stages, while tree initiation voltage appears different magnitude of decrease. There are 3 kinds of electrical tree during the experiments: branch tree, trunk tree and pine tree. The branch tree and pine tree are the primary shapes in the range of low frequency, while the bush tree is the primary shape in the range of HF. The dielectric spectroscopy of silicone rubber was also measured. At last, the influence of frequency on electrical tree in silicone rubber was analyzed. The repeated electro-mechanical stresses applied to the needle tip under high frequency may lead to the decrease of tree initiation voltage of silicone rubber. And with the increase of frequency, the serious erosion in silicone rubber by electrical tree may be caused by the great increase of dielectric losses.

关键词： Frequency Rubber Trees - insulation Shape measurement Dielectric losses Cable insulation Dielectrics and electrical insulation Voltage measurement Electric variables measurement Hafnium

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Novel active damping control scheme for a three-phase active rectifier with LCL-filter

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Diangong Jishu Xuebao/Transactions of China Electrotechnical Society 2008年第9期23卷 86-91页

作者： Huang, Yuqi Jiang, Xinjian Qiu, Arui State Key Lab. of Security Control and Simulation of Power Systems and Large Generation Equipments Tsinghua University Beijing 100084 China

A novel active damping control scheme is developed to eliminate stability problems arisen in the current control of a three-phase voltage source active rectifier (VSR) with LCL-filter. A converter side inductance voltage feedback loop is introduced in the traditional voltage oriented control to stabilize VSR. A simplified discrete model including the current control loop and LCL-filter is established with one sample delay, considering time delays induced by S/H (sampling and holding), processing and modulation. The amplification coefficient of the converter side inductance voltage feedback loop is tuned up to change the unstable poles of LCL-filter. Parameter estimate methods are used to remove unnecessary sensors. simulation and experiment of VSR with LCL-filter demonstrate the proposed active damping control scheme and the stability analyses.

关键词： Inductance

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Energy Management of a Residential Consumer with Uncertain Renewable generation: A Robust Dual Dynamic Programming Approach

Energy Management of a Residential Consumer with Uncertain R...

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Chinese control Conference (CCC)

作者： Dangwu Liu Zhongjie Guo Feng Chen Xiaodai Xue Shengwei Mei State Grid Anhui Electric Power CO. LTD Hefei P. R. China State Key Lab of Control and Simulation of Power Systems and Generation Equipments Tsinghua University Beijing China

ISBN: (数字)9789881563903

ISBN: (纸本)9781728165233

This paper studies the dynamic operation of a residential electric energy system with distributed renewable generation. Energy streams among the power grid, local renewable plant, storage unit, and demand are considered; the temporal volatility of renewable generation is described by an uncertainty set, and the optimal operation problem gives rise to a multi-stage robust optimization. To deal with the non-anticipativity issue, the robust model is solved via robust dual dynamic programming (RDDP) approach. The the cost-to-go function is approximated by iteratively updating the upper and lower bounds, which can be obtained from forward-pass and backward pass procedures. Case studies validate the performance and advantage of the proposed method.

关键词： Uncertainty Robustness Dynamic programming Upper bound Optimization Heuristic algorithms Energy storage

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Research on switching overvoltage in 1000 kV ultra-HVAC transmission line

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Zhongguo Dianji Gongcheng Xuebao/Proceedings of the Chinese Society of Electrical Engineering 2005年第SUPPL.期25卷 214-219页

作者： Xu, Wei Chen, Shui-Ming He, Jin-Liang Lab. of Control and Simulation of Power Systems and Generation Equipments Dept. of Electrical Engineering Tsinghua University Beijing 100084 China

Combined with a single circuit UHV power transmission project in one million voltage from Jincheng to Jingzhou via Nanyang which is reasoned by State power Grid Corp. of China, its switching overvoltages, including three-phases closing with no load and single-phase auto-reclosing, are considered. The switching overvoltages are calculated with Electromagnetic Transient Program (EMTDC). The calculation shows that the switching overvoltage is too high up to 1.80 pu if only with parallel resistor in circuit breaker or high performance ZnO arrester. Combining arrester and parallel resistor is a good measure to limit switching overvoltage without such high requirement on arrester's or resister's thermal capacity.

关键词： UHV power transmission

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Study of Non-Conventional Instrument Transformer and IEC61850 impact on current differential protection

Study of Non-Conventional Instrument Transformer and IEC6185...

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IEEE/PES Transmission and Distribution Conference and Exposition: Latin America

作者： K. L. S. Shenxing X. Dong Z. Bo State Key Lab of Control and Simulation of Power System and Generation Equipments Department of Electrical Engineering Tsinghua University Beijing 100084 China Tsinghua University Beijing Beijing CN State Key Laboratory of Control and Simulation of Power System and Generation Equipments Department of Electrical Engineering Tsinghua University Beijing China AREVA T&D Automation슠and Information Systems Stafford UK

Non conventional instrument transformer (NCIT) and IEC 61850 are crucial technologies in digital substations. But they bring some new uncertainties to protection IEDs, especially the time synchronization issue in current differential protection. The paper analyzes the time delay of transferring sampled values from NCIT to current differential relay in NCIT and IEC61850 based digital substation, then finds out the delay-non-deterministic problem, at last presents a novel current differential protection scheme by using phase-locked loops (PLL ) technology.

关键词： Substations Delay effects Ethernet networks Phase locked loops IEC Synchronization Data communication

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Distribution line automation system based on non-communication protection in the case of symmetrical fault

Distribution line automation system based on non-communicati...

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International Conference on Advanced power System Automation and Protection (APAP)

作者： Diqing Yin Kun Liu Xinzhou Dong Shenxing Shi Gang Xu Kai Wang North City Branch of Shanghai Power Company 200072 China Status Key Lab of Control and Simulation of Power Systems and Generation Equipments Dept. of Electrical Engineering Tsinghua University Haidian District Beijing 100084 China

Distribution line non-communication protection (DNCP) can quickly and selectively isolate unsymmetrical fault, but the performance of this distribution line automation system is not satisfying in the case of symmetrical fault. This paper proposes a scheme which can quickly isolate symmetrical fault and block the operation of BPS: DNCP which is closed to the source can operate instantaneously, that can avoid overheating damage of electrical equipment; when the magnitude of voltage falls, BPS will detect the magnitude of negtive voltage two cycles ago to make a decision, that can avoid the process of connecting to permanent fault and tripping again for the ring main unit. EMTP simulation results show the effectiveness of the scheme.

关键词： Circuit faults Circuit breakers Relays Automation power supplies Induction motors

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