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Two-stage heuristic-correction for dynamic reactive power optimization based on relaxation-MPEC and MIQP

Zhongguo Dianji Gongcheng Xuebao/Proceedings of the Chinese Society of Electrical Engineering 2014年第13期34卷 2100-2107页

作者： Ding, Tao Guo, Qinglai Bo, Rui Sun, Hongbin Wu, Wenchuan Zhang, Boming Yao, Zhengyi State Key Lab. of Control and Simulation of Power Systems and Generation Equipments Dept. of Electrical Engineering Tsinghua University Haidian District Beijing 100084 China Midwest ISO St. Paul 55108 United States Baoji Power Supply Bureau Baoji 721004 Shannxi Province China

To achieve a fast approach to the dynamic reactive power optimization model, a mixed integer nonlinear programming model was set up, with consideration of the discrete reactive power equipment operation limit and power grid security constraints, to minimize the transmission losses. Furthermore, a method called heuristic search and variable correction was proposed that for the first stage, the discrete variables are relaxed into continuous ones, which leads to an optimization model with equilibrium constraints. According to the optimal value of relaxed model, a mixed integer quadratic programming model is formulated to minimize the objective of approximation variance, satisfied the discrete switching operation constraints in primary model. For the second stage, the continuous variables are redressed with respect to the determined discrete variables. The impact of adjustment step and operation limit on the optimal solution was fully studied in IEEE 14-bus test system. Besides, the result of IEEE 30, 57, 118 test systems show that an optimal solution can fast be obtained by proposed method, and the precision satisfies the actual engineering, which can also employ the parallel technology. © 2014 Chinese Society for Electrical Engineering.

关键词： Integer programming

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INFLUENCES OF BREAKDOWN CHARACTERISTICS OF DISCONNECT SWITCH GAP ON RESIDUAL VOLTAGE

INFLUENCES OF BREAKDOWN CHARACTERISTICS OF DISCONNECT SWITCH...

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The ⅪⅩ International Conference on Gas Discharges and Their Applications

作者： YUE GONGCHANG GUAN YONGGANG LIU WEIDONG CHEN WEIJIANG LI ZHIBING State Key Lab of Control and Simulation of Power System and Generation Equipments Department of Electrical EngineeringTsinghua University State Grid Corporation of China China Electric Power Research Institute

The very fast transient overvoltages(VFTO) are generated during operation of disconnect switch (DS) of gas insulated switchgear(GIS). After the opening operation of DS,the load side busbar is left at a residual *** residual voltage is determined by the opening phase and the breakdown characteristics of SF6 gap of DS. This study obtains the breakdown characteristic of the test DS,including the dielectric strength recovery speed and polarity effect factor of gap of testing *** the stochastic property of DS opening phase,the opening process of DS is simulated by computer under different dielectric strength recovery speeds and polarity effect *** results show that the dielectric strength recovery speed and polarity effect factor have big influences over the residual *** proper value of dielectric strength recovery speed and polarity effect factor could make the residual voltage minor

关键词： simulation INFLUENCES OF BREAKDOWN CHARACTERISTICS OF DISCONNECT SWITCH GAP ON RESIDUAL VOLTAGE

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Comprehensive comparison and analysis of non-inverting buck boost and conventional buck boost converters

Comprehensive comparison and analysis of non-inverting buck ...

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作者： Weng, Xing Xiao, Xiang He, Weibin Zhou, Yongyan Shen, Yu Zhao, Wei Zhao, Zhengming State Key Lab of Control and Simulation Power Systems and Generation Equipment Department of Electrical Engineering Tsinghua University Beijing100084 China Guangdong Electric Power Research Institute Guangdong510080 China Dongguan Power Supply Bureau Guangdong Power Grid Company Dongguan523000 China

The non-inverting buck boost (NIBB) converter has attracted significant attention in recent years, as it shares ground between input and output, and the voltage stress of switches is lower. In order to investigate the differences between NIBB and conventional buck boost converters, a comprehensive comparison and analysis of these two converters were conducted in terms of their operation principles, which includes multi-mode control strategy and dual-edge modulation here, and also the characteristics of switches and passive components in the two converters were analysed. The results show that NIBB is better than conventional buck boost circuit in these aspects of electrical stress, power loss, cost, passive component volume, and so on. Two prototypes for the two converters with 10 kW/20 kHz were designed and simulated, respectively, for verifying the results. Analytical and simulated results confirmed the conclusions. © 2019 Institution of Engineering and *** right reserved.

关键词： Buck-Boost converter

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ANALYSIS OF THE MULTI-MODE OSCILLATIONS OF OFFSHORE WIND FARMS 18

ANALYSIS OF THE MULTI-MODE OSCILLATIONS OF OFFSHORE WIND FAR...

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18th International Conference on AC and DC power Transmission, ACDC 2022

作者： Fan, Yupeng Dong, Wenkai Li, Peng Qin, Yi Jiang, Haojie Xie, Xiaorong Datang Guoxin Binhai Offshore Wind Power Generation Co. Ltd Jiangsu Province Yancheng224000 China State Key lab of Control and Simulation of Power Systems and Generation Equipment Dept. of Electric Engineering Tsinghua University Beijing100084 China China Datang Corporation Science and Technology General Research Institute Ltd Beijing100040 China

ISBN: (数字)9781839537615

ISBN: (纸本)9781839537615

Multi-mode oscillation (MMO) is more prone to happen in the offshore wind farm (OWF) than the onshore, which seriously impacts the safe operation of the system. In this paper, the mechanism for the MMO of the OWF is analytically studied. First, the impedance model (IM) of a grid-connected OWF is derived with the AC submarine cable modelled as a distributed parameter circuit (DPC). Second, since the DPC of N n sections can be approximately seen as composed of N identical capacitances in daisy-chain connection, based on the consistent control theory for homogeneous systems, the IM of the DPC is decoupled into N subsystems, each of which is composed of a x circuit. The IM of the DPC is the weighted sum of the IMs of the N subsystems. As each x circuit has one tip (jump between ±90°) in the amplitude(phase)-frequency characteristics (APFC), the IM of the cable will have N tips (jumps) in the APFC and is much more prone to intersect with the IM of the OWF. Thus, resonance is more likely to happen at multiple frequency points. Finally, effectiveness of the methods proposed and conclusions drawn is validated via study cases. © ACDC 2022. All rights reserved.

关键词： Offshore wind farms

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power transmission mode to promote low-carbon development of load center

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Dianwang Jishu/power System Technology 2015年第3期39卷 663-668页

作者： Tian, Xin Sun, Yanlong Niu, Xinsheng Zhu, Xiubo Zhao, Guangfeng Shandong Power Economic Research Institute Shandong Electric Power Company Ji'nanShandong Province250001 China State Key Lab of Control and Simulation of Power Systems and Generation Equipments Dept. of Electrical Engineering Tsinghua University Haidian District Beijing100084 China State Grid Shandong Electric Power Company Ji'nanShandong Province250021 China

Regarding the power transmission mode from energy base to load center as the heart of the matter, a joint optimal operating model for both sending- and receiving- end power grids is established. In this model, the carbon emission is taken into the total system operation cost in the form of economic costs and taking the minimized total system operation cost as the objective the operation of the tie line and the generating unit in the receiving end power grid is scheduled. Based on the planning parameters for the power transmission from XilinGol League to Shandong, the case study on the application of the proposed model is performed and the results show that through reasonable power transmission mode the wind power accommodation space of the receiving end power grid can be fully utilized to accommodate the wind power generated in the sending power grid, thus the system operating cost is reduced while the low carbon development of power grid can be promoted effectively. ©, 2015, power System Technology Press. All right reserved.

关键词： Wind power

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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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Risk-constrained Economic Dispatch for power systems with Renewable Energy Sources and Compressed Air Energy Storage

Risk-constrained Economic Dispatch for Power Systems with Re...

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第三十八届中国控制会议

作者： Guangkuo Li Laijun Chen Yuguang Xie Bo Gao Tianwen Zheng Shengwei Mei State Key Lab of Control and Simulation of Power Systems and Generation Equipments (Dept. of Electrical Engineering Tsinghua University) State Grid Anhui Electric Power Research Institute Sichuan Energy Internet Research Institute Tsinghua University

Energy crisis and environmental concerns have led to the rapid development of renewable energy sources(RES). However, the fluctuating and unpredictable nature of RES reduce the reliability of the power systems. Using compressed air energy storage(CAES) is one of the main solutions to this problem. In this paper, three typical operation modes of CAES are adopted to improve the flexibility of the wind-CAES hybrid system, and a risk-constrained economic dispatch model considering the uncertainty of wind power and the part-load characteristics of CAES is proposed. Scenario generation and reduction technique is applied to model the uncertainties and a piecewise linearization method is used to incorporate the part-load features into the mixed integer linear programming model. The effectiveness of the proposed methodology is studied in a modified IEEE RTS 24-bus system.

关键词： economic dispatch compressed air energy storage wind generation uncertainty conditional value at risk

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Quasi-Uniform Magnetic Field Generated by Multiple Transmitters of Magnetically-Coupled Resonant Wireless power Transfer

Quasi-Uniform Magnetic Field Generated by Multiple Transmitt...

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International Conference on Electrical Machines and systems

作者： Yiming Zhang Ting Lu Zhengming Zhao Fanbo He Kainan Chen Liqiang Yuan State Key Lab of Control and Simulation of Power Systems and Generation Equipment Department of Electrical Engineering Tsinghua University Beijing China

ISBN: (纸本)9781479988068

Magnetically-coupled resonant wireless power transfer (MCR-WPT) has been a research focus in recent years. Multiple transmitters are employed to improve efficiency in a wide area. In this paper, the MCR-WPT system with two transmitters supplied by the same source is modeled and its equivalent circuit is depicted. The mutual inductance between the two transmitters is considered. Proper connection of the transmitters results in the enhancement of the magnetic field in certain areas. Based on the circuit theory, the explicit expression of the efficiency is derived. The quasi-uniform magnetic field and roughly equal efficiency are analyzed.

关键词： magnetic resonance multiple transmitters uniform magnetic field wireless power transfer

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Analyses on Frequency Transmission Characteristic of Traveling Wave in Distribution power System

Analyses on Frequency Transmission Characteristic of Traveli...

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2011 International Conference on Advanced power System Automation and Protection (APAP 2011)(2011年继电保护与电力系统自动化国际会议)

作者： Jun Wang Shenxing Shi Xinzhou Dong Bin Wang Stale Key Lab of Control and Simulation of Power Systems and Generation Equipments Dept. of Electrical Engineering Tsmghua University IIai-dian District. Beijing 100084 China

Under the skin effect caused by the alternating electromagnetic field, the transmission line parameters changes with frequency, and different line resistivity, surge impedance, wave speed are presented in one line under the different frequency bands of signal. This phenomenon is usually called Frequency transmission characteristic, which is mainly discussed in this paper. This paper first studied the line resistivity, wave speed and surge impedance of zero-mode component and line-mode component in different frequency bands. Then, the line structure and its effection on Frequency transmission characteristic are presented. Last, the frequency transmission characteristic on a certain line fault is discussed based on a typical distribution system model. The research in this paper is meaningful for future study on the fault feeder selection and fault location technology based on traveling wave in the distribution system.

关键词： Frequency transmission characteristic traveling wave distribution power system zero-mode component line-mode component wavelet transform

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