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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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IMPACT OF THE LOCATION OF DISCHARGE SOURCE ON THE PD SIGNAL IN GIS

IMPACT OF THE LOCATION OF DISCHARGE SOURCE ON THE PD SIGNAL ...

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The ⅪⅩ International Conference on Gas Discharges and Their Applications

作者： DENGWEI DING WENSHENG GAO WEIDONG LIU RUI FENG State Key Laboratory of Control and Simulation of Power System and Generation Equipment Department of Electrical EngineeringTsinghua University

ISBN: (纸本)9771003651221

In order to monitor the on-line condition of GIS and diagnose existing defects,the ultra high frequency(UHF) methods are widely used for detecting partial discharge(PD) owing to its sensitivity and anti-interference *** partial discharge will happen when the electric field is non-uniform because of the defects in *** location of the partial discharge source has an impact on electromagnetic wave generated from the *** the PD detection,the UHF signal acquired by the coupler in GIS is produced by the change in the electric field,so the characteristics of the signal are related with the position of the *** this paper,the distance between the PD source and the inner conductor of GIS is changed;the amplitude of time-domain signal and the frequency spectrum of the UHF signal are *** is discovered that the amplitude of time-domain signal is various with the distance between the defect and the inner conductor,as well as the frequency *** that, the mode of UHF signal in GIS is affected by the location of PD,the component of TEM mode and high order mode(TE mode and TM mode) change with the distance between the PD source and the inner conductor.

关键词： domain IMPACT OF THE LOCATION OF DISCHARGE SOURCE ON THE PD SIGNAL IN GIS

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Effects of manganese dioxide additives on the electrical characteristics of Al-doped ZnO varistors

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Science China(Technological Sciences) 2011年第8期54卷 2204-2208页

作者： LONG WangCheng HU Jun HE JinLiang LIU Jun ZENG Rong State Key Laboratory of Control and Simulation of Power System and Generation Equipment Department of Electrical Engineering Tsinghua University Beijing 100084 China

The effects of manganese dioxide (MnO 2 ) additives on the electrical characteristics of the Al-doped ZnO varistors are investigated. The leakage current densities of the samples decrease first and then increase again with the increase of the amount of MnO 2 additives. Correspondingly, the nonlinear coefficients of the samples keep on increasing and then decrease. In addition, the donor densities increase monotonously with the amount of the doped MnO 2 increasing. The effects of MnO 2 additives on the electrical characteristics of the samples are different from the conclusion of previous literatures. The reasons of the distinct effects are supposed to be related with the donor and interface state densities of the samples.

关键词： ZnO varistots manganese dioxide electrical characteristics low residual voltage ratio simulation

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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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IEEE International Conference on Automation Science and Engineering (CASE)

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

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.

关键词： Batteries Optimization Discharges (electric) Real-time systems Load forecasting Load modeling US Department of Defense

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Positive-sequence component based three-phase unbalanced power flow solution for distribution system with PV nodes

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Zhongguo Dianji Gongcheng Xuebao/Proceedings of the Chinese Society of Electrical Engineering 2012年第1期32卷 115-121页

作者： Li, Hongwei Sun, Hongbin Zhang, An'an Liu, Qingyou State Key Laboratory of Oil and Gas Reservoirs Geology and Exploitation Southwest Petroleum University Chengdu 610500 Sichuan Province China State Key Lab. of Control and Simulation of Power Systems and Generation Equipments Dept. of Electrical Engineering Tsinghua University Haidian District Beijing 100084 China

The traditional power flow methods aren't appropriate to the electrical distribution systems with distributed generators (DG). Therefore, a direct unbalanced three-phase power flow algorithm was presented in this paper. The proposed approach which was developed based on the path matrix, utilized the special topological structure of distribution systems and established the incident matrix of node voltages and injection currents. Based on the assumption that the positive-sequence voltage magnitudes of PV nodes are invariable, the relation of reactive power and compensation voltage for the PV nodes had been derived by the positivesequence component and path matrix. As a result, a new approach handling PV nodes of DG had been proposed and could be integrated into the proposed power flow method. It needn't introduce any additional active power at PV nodes and kept the positive-sequence voltage magnitudes on their scheduled values, considering that reactive power limits were not violated. The results of the 6-bus and the 69-bus test systems verified the validity and universality of the proposed methods. © 2012 Chin. Soc. for Elec. Eng.

关键词： Reactive power

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Synergistic utilization of coal and other energy- key to low carbon economy

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能源前沿 2011年第1期5卷 1-19页

作者： Weidou NI Zhen CHEN State Key Laboratory of Control and Simulation of Power System and Generation Equipment Department of Thermal EngineeringTsinghua UniversityBeijing 100084China

In China, coal is a dominant component of energy mix, and it is expected to remain as such over the next 30 to 40 years. Coal is expected to be used even more in power generation. The direct combustion of coal already has been causing severe pollution and ecological degradation, and it is quite difficult to address the need to reduce greenhouse gas (GHG) given the direct combustion of coal. Therefore, the polygeneration system based on coal gasification, which is one of the major examples of synergistic utilization of coal, is proposed. It is a comprehensive solution to meet the energy challenges China is facing. Furthermore, the synergy of fossil fuels (especially coal) with renewable energy, the synergy of different kinds of energy for energy storage, the synergy of centralized and distributed supply of different kinds of energy, and the synergy of different kinds of energy in smart energy grid (power, gas, heat, and water) are the keys to making China a low-carbon economy. Carbon dioxide (CO2) mitigation in China should begin from the coalchemical industry given their accumulated relevant experiences. The mitigation process should gradually be transformed into the 'IGCC + polygeneration + CCUS'.The objectives of this paper are to describe the synergistic utilization of coal, and to analyze the synergy of coal with other energy resources, and to propose the scientific and technological problems to achieve these synergies.

关键词： synergy clean and efficient utilization of coal coal-based polygenration CO2 mitigation energy storage

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An Energy-based Methodology for Locating the Source of Forced Oscillations in power systems

An Energy-based Methodology for Locating the Source of Force...

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IEEE International Conference on power system Technology

作者： Li Ying Shen Chen Liu Feng State Key Lab of Control and Simulation of Power Systems and Generation Equipment Tsinghua University Beijing China

Recently, several power grids of China came across low frequency oscillations which are difficult to explain by the traditional negative damping mechanism. Some researchers suggest that those oscillations be caused by external periodic disturbances according to the forced oscillation mechanism. It takes no doubt that the oscillation source location (means locating the disturbances) is imperative and decisive to eliminate such a kind of oscillations. This paper proposes a location methodology based on Energy Supply on Port derived from the Port-controlled Hamiltonian theory. By calculating the energy injected to the network at corresponding ports, the oscillation sources can be effectively located, even in complicated systems containing various kinds of control devices such as governors and exciters. Different from the traditional methodology based on eigen-analysis, the proposed methodology is naturally decentralized without the dependency on global measurements. Case studies on the standard 4-machine 2-area system and the IEEE-118 bus system show the effectiveness and efficiency of the proposed methodology.

关键词： Oscillation Source Location Forced Oscillation Port-controlled Hamiltonian Energy Supply on Port

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Substation switching electromagnetic transient analysis using the time domain integral equation with a high order implicit scheme

Substation switching electromagnetic transient analysis usin...

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IEEE International Symposium on Electromagnetic Compatibility (EMC)

作者： Hongjun Xiang Sughun Chang Jun Zou Jians heng Yuan Sergey V. Shenderey State Key Laboratory of Control and Simulation of Power Systems and Generation Equipments Department of Electrical Engineering Tsinghua University Beijing China Electrical Environment Group Korea Electrotechnology Research Institute Changwon South Korea

A fast electric field integral in time domain using the uneven discretization and the implicit scheme is proposed to calculate the switching electromagnetic transient at a substation. The switching transient currents and the resultant radiated electromagnetic field are calculated. The propose d approach has the strength to model the bus system at a substation with a more complicated and realistic configuration that is difficult to simulate using the circuit-based method, because all the electromagnetic couplings within the bus system are included globally. The proposed method might be one of good candidates to predicate the EMI level at a substation.

关键词： Transient analysis Switches Time domain analysis Wires Integrated circuit modeling Conductors

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Optimal design of the back-to-back IGBT-based converter with the concept of systematic safe operating area

Optimal design of the back-to-back IGBT-based converter with...

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2011 International Conference on Electrical Machines and systems, ICEMS 2011

作者： Zou, Gaoyu Zhao, Zhengming Yuan, Liqiang Wang, Xuesong Lu, Ting State Key Laboratory of Control and Simulation of Power System and Generation Equipment Department of Electrical Engineering Tsinghua University Beijing 100084 China

ISBN: (纸本)9781457710445

The key parameters of SOA (safe operating area) of semiconductor devices are hard to be measured when converter is operating, which is not helpful to protect converter at any time. On the other hand, surplus estimating method is widely used to design the main circuit. In order to guarantee the whole system works safely and improve utilization rate of devices, the concept of SSOA (systematic safe operating area) is presented. By determining the relationship of key parameters between devices and converter, the expression of SSOA is described quantitatively. Then it is implemented as a basic rule to design a back-to-back converter based on IGBT for 55kW induction motor optimally. Rated value of DC-link voltage and grid filter of the system is obtained reasonably as well. © 2011 IEEE.

关键词： Insulated gate bipolar transistors (IGBT)

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Design, simulation and analysis of the low stray inductance bus bar for voltage source inverters

Design, simulation and analysis of the low stray inductance ...

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2011 International Conference on Electrical Machines and systems, ICEMS 2011

作者： Yuan, Liqiang Yu, Hualong Wang, Xuesong Zhao, Zhengming State Key Laboratory of Control and Simulation of Power System and Generation Equipment Department of Electrical Engineering Tsinghua University Beijing 100084 China

ISBN: (纸本)9781457710445

Hard-switching technique under the high voltage and high current is one of main trends of high power inverters. Under this switching mode, the stray parameters of the commutating loops, especially the stray inductance of the DC bus bar, have significant influence on the switching process, electromagnetic interference and component stress of the semiconductor switches. It becomes one of the key points for the safe operation of inverters. Based on an actual 55kW inverter, the design, simulation and analysis for its bus bar is described in this paper. The bus bar model is built with the method of Partial Element Equivalent Circuit (PEEC), and the stray parameters are extracted from PEEC model and applied in the circuit simulation. Compared with the experimental results, the modeling validity is proved, and the simplified modeling process and design principles for complex physical bus bar are presented. © 2011 IEEE.

关键词： Circuit simulation

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