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Analysis and simulation research on cascading trips of multiple wind farms

Dianwang Jishu/power System Technology 2014年第6期38卷 1425-1431页

作者： Xu, Fengda Guo, Qinglai Sun, Hongbin Zhang, Boming Wang, Bin Li, Zhengshuo Ding, Tao Jia, Lin Xu, Xiaofei State Key Lab of Control and Simulation of Power Systems and Generation Equipments Dept. of Electrical Engineering Tsinghua University Haidian District Beijing 100084 China North China Grid Company Limited Xuanwu District Beijing 100053 China

A simulation based analysis is proposed to find out the most relative factors during the cascading process, which is significant to support the future voltage control schemes for wind integration region. A hierarchical distributed simulation platform is built, which contains both the transmission and wind farms' distribution grid. In this way both the coupling among wind farms and the detailed characteristics of device level can be considered. By simulating shunt capacitors, wind turbine generators and static var compensators (SVCs) under different control mode, the different impact to cascading trips process are analyzed. With the simulation, it is found that centralized integrated wind farms are so closed-coupled that variations of active or reactive power in one wind farm would cause great changes of voltages in wind farms nearby. Researching results also indicate that coordination of various reactive power implements is essential to system voltage safety.

关键词： Wind farm

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Applicable range analysis of optimized single-terminal fault location algorithm

Applicable range analysis of optimized single-terminal fault...

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

作者： Tian-xiao Huang Xin-zhou Dong Shen-xing Shi Bin Wang State Key Lab of Control and Simulation of Power Systems and Generation Equipments Dept. of Electrical Engineering Tsinghua University Haidian District Beijing 100084 China

Impedance method and single terminal travelling wave method are analyzed in paper, applicable scope of optimized solution is presented. Impedance method is of high robustness but low accuracy. Single terminal travelling wave method offers high accuracy but poor robustness. Optimized solution combines these two methods together, takes advantages of both methods. It is a great enhancement to single terminal fault location. This paper analyzed theoretical basis of optimized solution, proposed the calculation algorithm of fault location range using impedance method. Analyses of impedance method and single terminal travelling wave method show that the optimized solution is suitable for engineering application. Error analysis is proved correct by simulation.

关键词： Fault location Impedance Impedance measurement Transmission line measurements power transmission lines Frequency modulation Surges

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Analysis on Lightning Current and Position During Shielding Failure of High Voltage AC Transmission Lines

Analysis on Lightning Current and Position During Shielding ...

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2015 International Conference on simulation, Modelling and Mathematical Statistics(SMMS 2015)

作者： Shan-qiang GU Zhan-qing YU Xuan ZHOU Ze-zhong WANG Tong ZHU Bi-wu YAN Jin-liang HE Rong ZENG Chi-jie ZHUANG Electric Power Research Institute China State Grid LTD State Key Lab of Control and Simulation of Power Systems and Generation Equipments Department of Electrical Engineering Tsinghua University

Shielding failure of lightning is the key problem for safe operation of transmission lines. Compare to Electro-geometry Method, Leader Progress Method more suitable for lightning protection analysis because the physical model is used instead of empirical formula. The relationship between amplitude of lightning current and other parameters, such as wires position, ground tilt angle, was analyzed.

关键词： Lightning stroke Shielding failure Transmission Line Leader progress

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Discussion of protection and cascading outages from the viewpoint of communication

Discussion of protection and cascading outages from the view...

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

作者： RunBin Cao Xinzhou Dong Bin Wang Kun Liu Status Key Lab of Control and Simulation of Power Systems and Generation Equipments Dept. of Electrical Engineering Tsinghua University Haidian District Beijing 100084 China

power grid and communication network, which depends on each other to provide proper functionality, are becoming more and more coupled together. Failure of a fraction of nodes in communication networks may lead to a failure even a cascade of failures in power grid. Wide area protection is highly dependent on communication. The failure of communication in some part of wide area protection system will affect the realization of the function to prevent cascading outages and result in serious consequences. Based on Manchester, OPA and hidden failure cascading failure models and considered the feature of relay protection, an improved cascading failure model is established. Then it is used to analyze the dynamic process of communication fails in wide area protection system and IEEE 30 bus system is employed to demonstrate the efficiency of the proposed method. Results show that communication failure in protection system will accelerate the cascading outages of power grid. Effective solutions to reduce the communication risk are discussed. The work of this paper is availab.e for reference to analyze the process of cascading outages and design protection system preventing cascading outages.

关键词： power system faults power system protection Load modeling Wireless application protocol power system stability Load flow power grids

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Electrical tree initiation and propagation in silicone rubber under long-term AC aging

Electrical tree initiation and propagation in silicone rubbe...

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Conference on Electrical Insulation and Dielectric Phenomena, (CEIDP)

作者： Yunxiao Zhang Yuanxiang Zhou Ling Zhang Ming Chen Xu Zhang Yanchao Sha State Key Lab of Control and Simulation of Power Systems and Generation Equipments Tsinghua University Beijing Beijing CN State Key Lab of Control and Simulation of Power Systems and Generation Equipments Tsinghua University Beijing China North China Electric Power Research Institute Co Ltd Beijing Beijing CN North China Electric Power Research Institute Co Ltd. Beijing China

Electrical tree break-down is the major failure problem in cable accessories, however, mechanisms of the electrical tree initiation and propagation are still lack of deeply research, especially in silicone rubber (SIR) which is widely used as insulation material for cable accessories. Long-term aging (0- 1000 h) experiments under the different voltages were conducted to observe electrical tree initiation and propagation processes. In trees initiation stage, with increasing of applied voltage, electrical tree initiation probability becomes larger, while tree initiation time dramatically decreases. The experiment observations demonstrated four shapes of trees which are dominated. As applied voltage increasing, the numbers of electrical trees life-cycles increased and exponential relationship was found between tree length and magnitude of applied voltage. It is noted that charges, whose energy exceeding a certain critical value, destroy microstructure of dielectric accumulatively via injection and extraction, and cause electrical trees initiate when it accumulates to a visible extent.

关键词： Electrodes Aging power cables Electric fields Needles power cable insulation

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Study of a new grid-connected LCL filter for shunt active power filter

Study of a new grid-connected LCL filter for shunt active po...

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IEEE Conference and Expo Transportation Electrification Asia-Pacific (ITEC Asia-Pacific)

作者： Yi Wang Jian-zheng Liu Xing-Tao Xu State Key Lab of Control and Simulation of Power Systems and Generation Equipments Tsinghua University Beijing Beijing CN Jiangsu Electric Power Company Research Institute Nanjing China

LCL filter can improve the output current of the shunt active power filter. The paper proposes a resonant LCL filter structure with a LC high-frequency filter branches adding to LCL filter with damping resistor. By LC resonance effect, the switching frequency harmonics are filtered more efficiently and the loss of the system is reduced. The paper also builds the system modeling and analyzes the stability of the grid filter with the deadbeat control, then gives parameter selection methods and simulates with PSCAD/EMTDC. All these are verified through the experiments on a 70-KW shunt APF prototype using deadbeat controller.

关键词： power harmonic filters Damping Active filters Harmonic analysis power filters Switching frequency Resonant frequency

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Research on system protection with local information to prevent power grid blackouts

Research on system protection with local information to prev...

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

作者： Bin Wang Xinzhou Dong Kun Liu Runbin Cao Status Key Lab of Control and Simulation of Power Systems and Generation Equipments Dept. of Electrical Engineering Tsinghua University Haidian District Beijing 100084 China

Aimed at power system large-scale blackouts, the paper firstly analyzes the existing problems of current protective relaying and emergency control in power grid. A novel system protection based on local information, protecting both the equipment and power system secure is then proposed, which scheme consists of: identification of fault flow transferring identification, adaptive overload protection and active load shedding strategy. The processes and system structure are introduced, and the following research points are also discussed in this paper.

关键词： Helium Security

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A VCG Payment Scheme for Energy Storages in the Spot Market Considering Levelized-Cost-of-Storage

A VCG Payment Scheme for Energy Storages in the Spot Market ...

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power and Electrical Engineering (ACPEE), 5th Asia Conference on

作者： Jianing Liu Yue Zhao Zhuo Su Ke Wang Yujun He Power Dispatching and Control Center Guangdong Province Power Grid Co. Ltd Guangzhou China State Key Lab of Control and Simulation of Power Systems and Generation Equipments Tsinghua Univeristy Beijing China

Energy storages are considered as a key solution in the novel energy system with high penetration of renewables. However, the current power markets are not designed for the participation of energy storage as it has a variable cost. This paper investigates an efficient mechanism in which the energy storage submits his levelized cost of storage, then the storage receives a Vickrey-Clark-Grove payment equal to the increase in social welfare attributable to his presence. This mechanism can encourage the storage to truthfully submit the true operating cost and thus help to optimize the system operation. Moreover, the increments of the storage’s own interests and the social welfare are coincidental, so it is incentive compatible. Numerical tests show the advantages of the proposed mechanism over the marginal pricing mechanism.

关键词：

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A novel fault locator for power distribution system with neutral non-effectively grounded

A novel fault locator for power distribution system with neu...

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

作者： Shenxing Shi Xinzhou Dong State Key Lab of Control and Simulation of Power Systems and Generation Equipments Dept. of Electrical Engineering Tsinghua University Haidian District Beijing 100084 China

Fault locator for power distribution system with neutral non-effectively grounded should locate phase-to-phase fault and single-phase-to-ground fault respectively. For phase-to-phase fault, the point can be located by power-frequency impedance. However, for single-phase-to-ground fault with limited power-frequency current not more than load current, a novel fault location technology should be developed. The paper will present a practical single-phase-to-ground fault location based on fault generated traveling waves acquired from one phase current transducer and zero sequence current transducer at first. Then implementation of the novel fault locator is proposed including hardware design and software flowchart. At last field tests will be made to verify the feasibility of the fault locator.

关键词： power distribution Fault location Random access memory Impedance Voltage measurement Current measurement

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Research on the process of power flow transferring and its identification method

Research on the process of power flow transferring and its i...

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

作者： Kun Liu Xinzhou Dong Bin Wang Shenxing Shi State Key Lab of Control and Simulation of Power Systems and Generation Equipments Dept. of Electrical Engineering Tsinghua University Haidian District Beijing 100084 China

This paper analyzes the general process of power flow transferring and divides it into four parts: 1) the process of first phase selection after fault occurs; 2) the process of selective action at the first time; 3) the process of second phase selection and status confirmation; 4) the process after status confirmation. It points out that the issue of asymmetrical flow transferring is a critical process which must be put emphasis on. Then it proposes a method to identify this process, and discuss different solution methods.

关键词： Circuit faults Fault diagnosis Grounding Voltage measurement Protective relaying Oscillators Impedance

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