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International Conference on Electrical Machines and systems (ICEMS)

作者： Kui Wang Yongdong Li Zedong Zheng State Key Laboratory of Control and Simulation of Power System and Generation Equipments Tsinghua University Beijing China

Five-level active neutral-point-clamped (ANPC) converter is a newly emerging topology which can overcome the drawbacks of traditional neutral-point clamped (NPC) converters and flying-capacitor (FC) converters. Its dc-link is subdivided into two equal parts and the main problem is the neutral-point (NP) potential balancing. In this paper, a NP potential balancing algorithm based on zero-sequence voltage injection is presented. By calculating the NP currents of all key zero-sequence voltages, the most appropriate zero-sequence voltage is selected to generate the demanded NP current. Moreover, by further limiting the span of injected zero-sequence voltages, the NP balancing algorithm can make the two IGBTs connected in series operate at fundamental frequency. A three-phase five-level ANPC inverter prototype was built up and experimental results are presented to verify the validity of this algorithm.

关键词： Capacitors Electric potential Switches Voltage control Inverters Insulated gate bipolar transistors Heuristic algorithms

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Zero impedance branch based substation three-phase nonlinear state estimation method

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Zhongguo Dianji Gongcheng Xuebao/Proceedings of the Chinese Society of Electrical Engineering 2011年第25期31卷 73-80页

作者： Li, Qingxin Sun, Hongbin Wang, Jing Zhang, Boming Wu, Wenchuan Guo, Qinglai State Key Lab of Control and Simulation of Power Systems and Generation Equipments Dept. of Electrical Engineering Tsinghua University Haidian District Beijing 100084 China

A substation three-phase nonlinear state estimation method based on zero impedance branches is presented in order to eliminate topology and analogy errors at substation level and accordingly enhance the control center state estimation reliability and accuracy. Measurements from different apparatus are utilized in substation, such as remote terminal unit (RTU) and phasor measurement unit (PMU) three-phase data. A breaker-oriented nonlinear three-phase state estimation model is established on Kirchoff's current law (KCL) , in which analog bad data and topology bad error identification can be decoupled, realizing real-time three-phase unbalanced degree monitoring at substation level. It is shown that this method is very fast and easy for implementation and can provide high measurement redundancy and reliable results. The test results show that the proposed approach is very effective. © 2011 Chinese Society for Electrical Engineering.

关键词： state estimation

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Design of IEC 61970 based information exchange model for coordinated automatic voltage control among multi control centers

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Dianwang Jishu/power system Technology 2011年第3期35卷 205-210页

作者： Wang, Bin Guo, Qinglai Sun, Hongbin Zhang, Boming Wu, Wenchuan State Key Lab of Control and Simulation of Power Systems and Generation Equipments Dept. of Electrical Engineering Tsinghua University Haidian District Beijing 100084 China

Standardization is the development tendency of information exchange among control centers. Based on the standard in IEC 61970, an information exchange model suitable for coordinated automatic voltage control (CAVC) among multi control centers is proposed. Firstly, the contents of information flow of CAVC is analyzed and the definition of coordinated control model for information exchange is given;then the common information model is extended and a standardized information model for CAVC is designed;and then based on component interface specification, a standardized information exchange interface for CAVC is designed and its architecture for information exchange as well as its information exchange procedure are given. The presented information exchange model possesses wide application prospect in the implementation of information exchange among multi CAVC control centers for future smart grids.

关键词： Voltage control

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印度大停电与继电保护的三大功能

印度大停电与继电保护的三大功能

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2012年中国智能电网学术研讨会

作者： DONG Xin-zhou 董新洲 CAO Run-bin 曹润彬 WANG Bin 王宾 SHI Shen-xing 施慎行 Dominik Bak State Key Lab of Control and Simulation of Power Systems and Generation Equipments Tsinghua Universi 清华大学电力系统及发电设备安全控制和仿真国家重点实验室北京 100084

简介了印度电网在2012年7月30日和7月31日发生的两起大停电事故。两起事故均起源于同一回输电线路距离保护Ⅲ段因过负荷保护动作跳闸，并导致其他设备继电保护的不合理动作而引发连锁跳闸，造成大面积停电。印度大停电事故暴露了现有电... 详细信息

简介了印度电网在2012年7月30日和7月31日发生的两起大停电事故。两起事故均起源于同一回输电线路距离保护Ⅲ段因过负荷保护动作跳闸，并导致其他设备继电保护的不合理动作而引发连锁跳闸，造成大面积停电。印度大停电事故暴露了现有电力系统的脆弱性，尤其是继电保护在过负荷和系统振荡情况下的动作缺陷。基于对停电事故中继电保护行为的分析，提出了满足现代电网需求的继电保护三大功能：面向系统安全的系统保护功能、预防性保护功能和快速切除故障设备功能。

关键词：停电事故继电保护过负荷故障处理

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Implementation of non-communication protection of double circuit line systems based on integrated protection platform

Implementation of non-communication protection of double cir...

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2011 International Conference on Advanced power system Automation and Protection, APAP 2011

作者： Hu, Xi Dong, Xinzhou Wang, Bin Shi, Shenxing Liu, Kun Li, Youyi State Key Lab. of Control and Simulation of Power Systems and Generation Equipments Dept. of Electrical Engineering Tsinghua University Haidian District Beijing 100084 China Research Ltd. Chaoyang District Beijing 100016 China

ISBN: (纸本)9781424496198

The implementation of non-communication protection of double circuit line systems based on two independent relays has disadvantages like information shareless,complex connection and lack of economic. This paper researched the implementation of non-communication protection of double circuit line systems based on one relay - the integrated protection platform. Hardware structure of the integrated protection platform is described, and software flow of non-communication protection of double circuit line systems which implemented on the integrated protection platform is also described. Large number of RTDS experiments proved that, according to various asymmetrical fault and symmetrical fault, this protection scheme has reliable and sensitive action performance. It is proved that the implement non-communication protection of double circuit line systems based on the intergrated protection platform is feasible. © 2011 IEEE.

关键词： Timing circuits

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An Improved Virtual Resistance Damping Method for Grid-Connected Inverters with LCL Filters

An Improved Virtual Resistance Damping Method for Grid-Conne...

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2011 IEEE Energy Conversion Congress and Exposition (ECCE 2011)

作者： Yi Lei Zhengming Zhao Fanbo He Sizhao Lu Lu Yin State Key Laboratory of Control and Simulation of Power System and Generation Equipment Department of Electrical Engineering Tsinghua University 100084 Beijing P. R. China

ISBN: (纸本)9781457705427;9781457705410

In renewable energy generations, LCL filters are commonly used to connect in series with the output ports of the converter to smooth the currents flowing into the grid due to their enhanced attenuation ability and smaller inductance compared to single L filters. However, the inherent resonance of an LCL filter makes the control of such a system challenging, and different passive and active damping strategies have been developed till now. This paper aims to the damping problems of LCL filters and proposes a new approach to realize active damping. Based on traditional virtual resistance damping strategy, the new algorithm employs a lead compensation block in the capacitor current feedback loop so as to alleviate the impact of control delay. It is easy to be transformed from conventional virtual resistance damping method since just an additional digital filter is needed. Theoretical analyses for the essence equivalent relationship between passive damping and virtual resistance damping, as well as the impact investigation of control delay are made in details. The results show that the traditional virtual resistance active damping method is equivalent to passive damping of connecting damping resistance in parallel with the capacitor in the control block diagram, while the proposed virtual resistance active damping method is equivalent to passive damping of connecting damping resistance in series with the capacitor in the control block diagram. Both simulation and experimental results have verified the feasibility.

关键词： absorption of shock BLOCK DIAGRAM Capacitors Filters Virtual Equivalent damping force control block

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A parallel based real-time electromagnetic transient simulator for IPS

A parallel based real-time electromagnetic transient simulat...

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IEEE Electric Ship Technologies Symposium, ESTS

作者： Yuan Gong Laijun Chen Ying Chen Yin Xu State Key Laboratory of Control and Simulation of Power System and Generation Equipments Department of Electrical Engineering Tsinghua University Beijing China

IPS has many special characteristics, such as using multi-phase, multi-frequency and hybrid AC/DC devices. As a result, existing electromagnetic transient simulators developed for power systems on land do not apply to IPS. This paper aims to build up a parallel based real-time electromagnetic transient simulator for IPS. A fast multi-switching process method for parallel electromagnetic transient simulations is coined to handle the tremendous switch events in IPS. To solve the difficulties brought by multi-phase machines in IPS, a multilevel hybrid parallel algorithm is forged through the combination of component level and network level parallelization. Based on the key techniques mentioned above, a parallel simulator is built up. Through sufficient testing to typical examples of IPS, the accuracy and high-efficiency of the simulator are proved.

关键词： Computational modeling Switches Generators Real time systems Parallel algorithms Circuit faults Testing

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Study on the loss reduction of high-efficient high-voltage series induction motors

Study on the loss reduction of high-efficient high-voltage s...

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International Conference on Electrical Machines and systems (ICEMS)

作者： Bai Lingyun Zhao Zhengming Lei Yi Wang Shuping State Key Laboratory of Control and Simulation of Power System and Generation Equipment Department of Electrical Engineering Tsinghua University Beijing China Anhui Electrical Research Institute Hefei China

On the basis of analyzing the composition of losses in high-efficient high-voltage asynchronous motors, the approaches of increasing the efficiency of the motors is investigated in this paper. The approaches concern with the improvement of material, winding, fan, magnetic groove and so on. By taking the economy and efficiency into account synthetically, the design of the YKK series induction motors is carried on, and it is realized by software simulation.

关键词： Magnetic flux Windings Induction motors Rotors Perpendicular magnetic anisotropy Copper

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Lightning Overvoltage Suppression of power Transformer in UHV GIS by Ferromagnetic Ring

Lightning Overvoltage Suppression of Power Transformer in UH...

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第七届亚太防雷国际会议

作者： Xiao Zhang Jinliang He State Key Laboratory of Control and Simulation of Power System and Generation Equipments Department of Electrical EngineeringTsinghua UniversityBeijing 100084China

Lightning overvoltage protection is of great importance to the safety of UHV *** widely used arresters can only suppress the magnitude of lightning overvoltage but lack efficiency on alleviating the *** practice, insulation failure of UHV transformer is often reported.A new protection method is proposed in this paper using ferromagnetic ring as supplement to arresters to suppress lightning overvoltage in UHV ***, equivalent model based on the characteristic of ferromagnetic material and factual dimension of the ring is established for *** of an actual 1000kV GIS is carried out to thoroughly evaluate the lightning overvoltage suppressing effect of ferromagnetic rings with different materials and structure dimensions.

关键词： ferromagnetic ring lightning overvoltage UHV

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Research on characteristics of surface electric field on transmission lines under lightning stroke

Research on characteristics of surface electric field on tra...

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2011 7th Asia-Pacific International Conference on Lightning, APL2011

作者： Li, Qian Yu, Zhanqing Zeng, Rong Zhang, Yong Li, Zhizhao Zhuang, Chijie Liao, Yongli State Key Lab. of Control and Simulation of Power Systems and Generation Equipments Department of Electrical Engineering Tsinghua University Haidian District Beijing 100084 China Department of Mathematical Sciences Tsinghua University Haidian District Beijing 100084 China Electric Power Research Institute CSG Guangzhou China

ISBN: (纸本)9781457714665

Lightning is a major cause of power interruptions in power transmission lines. Nowadays the Leader Progression Model is an advanced method to evaluate the shielding failure probability of transmission lines. Calculating the surface electric field on phase conductors and ground wires precisely is important, because the surface electric field has great effect on the upward leader inception. In this paper, the influence of lightning current and some other factors on surface electric field were analyzed. © 2011 IEEE.

关键词： Electric lines

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