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排序方式: 共有739条查询结果,搜索用时 15 毫秒
1.
Le Van Dai Xinran Li Peiqiang Li Le Cao Quyen 《IEEJ Transactions on Electrical and Electronic Engineering》2016,11(5):577-585
The increase in the scale and complexity of interconnected power systems leads to multiple electromechanical oscillations. Therefore, the electric network needs to be made more stable. One type of Flexible alternating current transmission systems (FACTS) devices, namely the static VAr compensator (SVC), can be installed at buses to increase the stability margins and dampen the power system oscillations by exchanging capacitive and/or inductive load to maintain and/or control specific parameters of electrical power systems. The efficiency and performance of the SVC depend on its optimal location. Consequently, seeking the optimal placement for SVC has become a key issue. In this paper, we propose a novel method to find the optimal location for the SVC based on a two‐step approach. First, an energetic approach based on the combination of the controllability Gramian critical energy analysis with the balanced realization reduction technique is used to search for several feasible locations; then the transient stability is analyzed to compare and determine an optimal location through various test cases. The effectiveness of the proposed method has been demonstrated on the IEEE 39‐bus England power system and compared with the modal controllability index. © 2016 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. 相似文献
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An extended discrete autoregressive model for variable bit rate video traffic encoded by scalable video codec 下载免费PDF全文
Sima Ahmadpour Zohreh Toghrayee Tat‐Chee Wan 《International Journal of Communication Systems》2015,28(18):2239-2254
Designing an effective and high performance network requires accurate characterization and modeling of network traffic. This paper provides a study of the transmission, modeling, and analysis of variable bit rate (VBR) video, which is fundamental for designing protocols and for effective utilization of networks in video transmission. To meet the specified requirements of future networks, the scalable video codec (SVC) was chosen as the video compression standard. The main objective of this work was to propose a statistical model that will allow better coordination between generated SVC video traffic and original video traffic. The performance of the proposed model was evaluated by comparing the model with three existing low‐complex statistical models using graphical and statistical measurements as well as cross‐validation. For all evaluation techniques, the accuracy of the proposed model was evaluated, and the frame size distribution of the modeled traffic was found to match that of the original video traffic better than other existing models. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
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Voltage Control of Static Var Compensator for a Remote System Interconnected by Long‐Distance AC Cables 下载免费PDF全文
Yuji Tamura Shinji Takasaki Yasuyuki Miyazaki Hideo Takeda Shoichi Irokawa Kikuo Takagi Naoto Nagaoka 《Electrical Engineering in Japan》2014,186(3):19-30
The voltage variation in a remote system is large when the system is connected by long‐distance AC cables due to the cable capacitance. In Japan, the longest 54‐km 66‐kV AC submarine cable interconnection between the Kyushu mainland and Goto Islands was commissioned in 2005. It was requested to mitigate the voltage variation caused by switching off and on one circuit of the two circuits in the AC cables when a fault occurs. Since the conventional voltage control methods such as transformer tap changer or shunt capacitor and reactor banks are not sufficient because of their slow response time, a static var compensator (SVC) was installed on the Goto Islands. In such an application, an SVC control method should be developed so as not to override the existing voltage control systems. This paper describes the SVC control method developed for the Goto Islands AC interconnection project, which can be applied to similar situations. The effectiveness of the control method was verified by the results of effective value simulation and of field testing, which was implemented before the SVC was commissioned in 2007. © 2013 Wiley Periodicals, Inc. Electr Eng Jpn, 186(3): 19–30, 2014; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.22337 相似文献
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The inter-area oscillations are common in power systems and can occur due to the changes in the load or generating power especially in long transmission lines. This paper presents the design of a robust fixed-order loop shaping controller to damp out the inter-area oscillations and to enhance the stability of the power system. The proposed loop shaping method is based on the shaping of the open-loop transfer function in the Nyquist diagram through minimizing the quadratic error between the actual and the desired open loop transfer functions in the frequency domain. The proposed method is robust with respect to multi-model uncertainty. Despite other robust controller design methods, the proposed approach deals with the entire system i.e. there is no need to reduce the system and still leads to a lower order controller. In addition, most of the robust methods are heavily dependent on selecting some weight filters which is not required in the proposed approach. This method is applied to the two-area four-machine system and 68 bus system and the effectiveness and robustness of the proposed method in damping inter-area oscillations are validated using case studies. 相似文献
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无线网络中基于H.264/SVC的RoI视频流传输 总被引:2,自引:1,他引:1
在无线网络中,由于无线终端的多样性和无线信道带宽多变、易受干扰,视频传输面临着极大的挑战,针对无线网络的这些特性,为了能满足不同终端的不同需求,对H.264/SVC码流进行RoI(感兴趣区域)码流转换;为提高传输效率,提出一种基于丢包率检测的带宽估计模型。然后,在NS2上建立一个仿真系统,对所提算法进行验证,结果表明,所提算法使得视频流在无线网络中进行可靠地传输,并且提高了视频的主观效果。 相似文献
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阐述了目前对于风电场内无功不足进行补偿的主要方式是在异步风力发电机端并联电容器组,随着电力电子技术的迅猛发展,这种补偿方式已经显现出明显弊端,提出将动态无功补偿装置应用到风电场中已经成为一种必然趋势,给出了风电机组模型、动态无功补偿装置模型;建立了并网风电场的仿真模型;将两种动态无功补偿装置分别应用到风电场中并进行了仿真对比。 相似文献
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