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The Influence of Boundary Conditions on The Stability of Repetitive Processes Modelled as 2D Linear systems

IFAC Proceedings Volumes 1996年第1期29卷 1599-1602页

作者： Eric Rogers David H Owens Image Speech & Intelligent Systems Research Group Department of Electronics & Computer Science University of Southampton Southampton S017 1BJ UK Centre for Systems and Control Engineering School of Engineering University of Exeter Exeter EX4 4QF UK

Repetitive, or multipass, processes are uniquely characterized by a series of sweeps, or passes through a set of dynamics defined over the so-called pass length which is finite and constant. The unique systems theoretic/control problem is that the sequence of outputs, or pass profiles, can contain oscillations which increase in amplitutde in the pass to pass direction. These processes can be modelled as a class of quarter plane causal 2D linear systems and this paper shows that the boundary (or pass initial) conditions alone can destabilize them. Hence they must be 'adequately modelled' in a given application and it is the boundary conditions which essentially distinguish the dynamic behaviour of linear repetitive processes from other classes of 2D linear systems.

关键词： Multi-dimensional systems Stability Criteria Tests

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Fast and accurate method to measure interharmonics in power systems

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EUROPEAN TRANSACTIONS ON ELECTRICAL POWER 1996年第3期6卷 169-174页

作者： Dai, X Gretsch, R [?]Associate Prof. Dr.-Ing. Xianzhong Dai (1954) received the Dr. degree (Elec. Eng.) from Tsinghua University of China in 1986. In 1988 he joined Southeast University as Associate Professor. In 1991 he became Humboldt Research Fellow and worked for two years at University of Erlangen-Nurnberg/Germany. His research work is focused to real-time control measurement and computer application on reactive power and harmonics compensation in power systems. (Automatic Control Engineering Department Southeast University Nanjing Jiangsu P. R. China)

In order to improve the resolution of spectrum analysis, the traditional method is to take more sampling periods, e. g. 50 sampling periods corresponding to the spectrum interval of I Hz. This method is not suitable to the interharmonic measurement, because most interharmonics vary rather quickly with the time and so the analysis results based on long time sampling may be useless. In this paper the zero-padding technique with short sampling time is used to resolve interharmonics, and the zoom FFT is used to decrease the computation time in order to meet the needs of real-time measurement. The simulating computation shows that the resolution for two adjacent frequency components is usually sufficient to measure harmonics and interharmonics in power systems with acceptable short sampling and computation time. This method is also suited to analyse harmonics and interharmonics when there exists an undesirable asynchronous deviation between the sampling period and the signal period.

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On Measures of Non-Integrability of Pfaffian systems

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IFAC Proceedings Volumes 1996年第1期29卷 2132-2137页

作者： Andrzej Banaszuk John Hauser Willem M. Sluis Richard M. Murray Department of Mathematics University of California Davis CA 95616-8633 Department of Electrical and Computer Engineering University of Colorado Boulder CO 80309-0425 Control and Dynamical Systems 104-44 California Institute of Technology Pasadena CA 91125 Division of Engineering and Applied Science California Institute of Technology Pasadena CA 91125

Many problems in nonlinear control theory (like, for instance, feedback linearization problem) leed to examination of integrability of a Pfaffian system. In a generic case a Pfaffian system is not integrable. Therefore, how to approximate non-integrable Pfafian systems by integrable ones and how this approximation can applied in practice appears to be a natural and important problem. In the present paper we establish some measures of non-integrability of Pfaffian system of arbitrary dimension and discuss their relation to approximations of non-integrable Pfaffian systems by integrable ones. Our work is motivated by expected applications to approximate feedback linearization of multi-input nonlinear systems.

关键词： Nonlinear systems differential geometry differential forms Pfaffian systems feedback linearization

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Application of fuzzy logic technology for spatial load forecasting

Application of fuzzy logic technology for spatial load forec...

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IEEE PES Transmission and Distribution Conference and Exposition

作者： Mo-yuen Chow Hahn Tram Department of Electrical and Computer Engineering North Carolina State University Raleigh NC USA Systems Control-Distribution Automation ABB Power Transmission and Distribution Company Inc. Cary NC USA

ISBN: (纸本)0780335228

Utilities are required to provide reliable power to customers. In the design stages, utilities need to plan ahead for anticipated future load growth under different possible scenarios. Their decisions and designs can affect the gain or loss of millions of dollars for their companies as well as customer satisfaction and future economic growth in their territory. This paper proposes and describes the general methodology to use fuzzy logic to fuse the available information for spatial load forecasting. The proposed scheme can provide distribution planners other alternatives to aggregate their information for spatial load forecasting.

关键词： Fuzzy logic Load forecasting Power system reliability Costs Power system planning Geographic Information systems Economic forecasting Distributed computing Customer satisfaction Power generation economics

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Methodology of urban re-development considerations in spatial load forecasting

Methodology of urban re-development considerations in spatia...

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IEEE PES Transmission and Distribution Conference and Exposition

作者： Mo-yuen Chow Hahn Tram Department of Electrical and Computer Engineering North Carolina State University Raleigh NC USA Systems Control-Automated Distribution ABB Power Transmission and Distribution Company Inc. Cary NC USA

ISBN: (纸本)0780335228

Load forecasting in power systems is an important subject and has been studied from different points of view in order to achieve better load forecasting results. This paper addresses one of the challenges in spatial load forecasting area, urban re-development, and presents a theory and methodology to incorporate urban re-development into spatial load forecasting considerations.

关键词： Load forecasting Substations Energy consumption Power system planning Cities and towns Power systems Urban planning Power system analysis computing Regression analysis Expert systems

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Phase correction for coherent noise reduction in short-range radar measurements

Phase correction for coherent noise reduction in short-range...

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IEEE International Symposium on Geoscience and Remote Sensing (IGARSS)

作者： S.G. Beaven S.P. Gogineni P. Kanagaratnam Development Test & Evaluation Division Naval Command Control and Ocean Surveillance Center San Diego CA USA Radar Systems and Remote Sensing Laboratory Department of Electrical and Computer Engineering University of Kansas Lawrence KS USA

Short-range scatterometer systems are used to obtain radar backscatter signatures for understanding the interaction between electromagnetic energy and geophysical media in a number of remote sensing applications. Unlike long-range and intermediate-range radar systems, the sensitivity of short-range radars is not limited by thermal noise, but rather by reflections and leakage signals from the antenna and RF section. These leakage signals and their sidelobes are the primary sources of unwanted signals (coherent noise) in short-range FM radar systems. The authors have employed coherent noise reduction techniques to reduce the effects of these unwanted signal sources. Reduction of these coherent noise sources is critical to obtaining accurate backscatter measurements from geophysical targets. Recent advances include the use of phase correction to overcome limitations due to drift of local oscillators and effects of temperature changes on the system. The authors present results from the standard and phase-corrected coherent noise reduction techniques. These techniques increased the dynamic range of field and laboratory measurements of radar backscatter from sea ice and allows the authors to use data from past experiments that had previously been discarded due to low signal-to-noise ratio.

关键词： Noise reduction Radar antennas Radar remote sensing Backscatter Radar measurements Geophysical measurements Sea measurements Radar applications Radar scattering Electromagnetic scattering

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Computing the trajectories generated by discrete linear repetitive processes

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Zeitschrift fuer Angewandte Mathematik und Mechanik, ZAMM, Applied Mathematics and Mechanics 1996年第SUPPL 5期76卷 159-159页

作者： GaLkowski, K. Rogers, E. Owens, D.H. Technical University of Wroclaw Institute of Telecommunications and Acoustics Poland University of Southampton Department of Electronics and Computer Science Image Speech and Intelligent Systems Group Southampton SO9 5NH United Kingdom University of Exeter Centre for Systems and Control Engineering Exeter EX4 4QF United Kingdom

Computing the trajectories generated by an arbitrary system or process is extremely important for its analysis, especially for control and stability investigations. This paper analyses the fundamental matrix sequence (a discrete counterpart of the transition matrix in the continous case) for a linear unit memory repetitive process. The main result refers to the representation of the repetitive process in terms of the general singular Kurek model.

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Learning augmented recursive estimation for uncertain nonlinear dynamical systems

Learning augmented recursive estimation for uncertain nonlin...

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IEEE International Symposium on Intelligent control (ISIC)

作者： S.C. Draper R.S. Mangoubi W.L. Baker Department of Electrical Engineering and Computer Science M.I.T. Cambridge MA USA Control and Dynamical Systems Division C. S. Draper Laboratories Inc. Cambridge MA USA Division of Engineering and Applied Sciences Harvard University Cambridge MA USA

This paper describes a learning augmented recursive estimation approach for nonlinear dynamical systems having unmodeled nonlinearities. Utilizing a passive spatially-localized learning system, an approximation of the unknown nonlinearity is synthesized online, based on state and parameter estimates from a nonlinear recursive estimator (an adaptive form of the extended Kalman filter). The learned model of the nonlinearity is used, in turn, to improve the performance of the recursive estimator. We demonstrate the approach on a second-order, mass-spring-damper system, where the spring stiffness is a nonlinear function of position. Simulation results indicate that, relative to more traditional adaptive estimation schemes, markedly improved estimation performance can be achieved.

关键词： Recursive estimation Nonlinear dynamical systems State estimation Learning systems Function approximation Filters Parameter estimation Springs Adaptive estimation Uncertainty

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Sensor diagnosis system combining Immune Network and Learning Vector Quantization

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ELECTRICAL engineering IN JAPAN 1996年第5期117卷 44-56页

作者： Kayama, M Sugita, Y Morooka, Y Hitachi Ltd. Received his Master's degree in 1984 from Osaka University. He joined the Hitachi Research Laboratory of Hitachi Ltd. in 1984. He was a Visiting Researcher at the University of California Los Angeles from 1990 to 1991. He is engaged in research on control of FA systems and control application of neural networks. He received a Paper Award from the I.E.E. Japan in 1995. Received his Master's degree in 1992 from Okayama University. He joined the Hitachi Research Laboratory of Hitachi Ltd. in 1992. He is engaged in research on system control of steel plants and control application of neural networks. Graduated in 1965 from the Department of Control Engineering Kyushu Institute of Technology. He received his Ph.D. later. He joined the Hitachi Research Laboratory of Hitachi Ltd. in 1965. He is currently a Supervising Researcher at the Laboratory. He is engaged in research on computer control systems. He is engaged mainly in development of multivariable control knowledge control and system engineering of steel plants. He received a Paper Award from the I.E.E. Japan in 1995. He is a member of the Society of Instrument and Control Engineers and the Information Processing Society of Japan.

A distributed diagnosis system combining Immune Network (IN) and Learning Vector Quantization (LVQ) for detecting fault sensors accurately in industrial plants is proposed. It has two execution modes, namely, its training mode where LVQ extracts correlation between each two sensors from their outputs when they work properly, and its diagnosis mode, where LVQ contributes to testing each two sensors using the extracted correlation, while IN contributes to determining fault sensors by integrating these local testing results obtained from LVQ. Discussed here is how to improve diagnosis capability of the developed system. It is shown that the thresholds can be determined effectively by the constraint that the hyperregion corresponding to the normal sensor outputs in each quantization vector space is a single region. Diagnosis capability of the developed system is evaluated using a prototype system for detecting fault sensors of a reheating furnace plant. With the proposed method, abnormal sensors, such as aged deteriorated ones, which have been difficult to be detected only by checking each output of sensor independently, are possible to be specified.

关键词： immune network vector quantization fault diagnosis sensor learning

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Development of transient stability controller system (TSC) based on on-line stability calculation

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ELECTRICAL engineering IN JAPAN 1996年第4期117卷 61-79页

作者： Ota, H Inoue, T Ito, H Fukushima, N Omata, K Morita, K Kokai, Y Chubu Electric Power Co. Graduated in 1955 from the Department of Electrical Engineering of the Faculty of Engineering University of Tokyo and joined Chubu Electric Power Co. in the same year. He is engaged mainly in developing technology for construction planning as well as protection stabilization and automatic control of power systems. He is currently a Director and Vice President of the company. He received an OHM Technology Award in 1971 and an Achievement Award from the I.E.E. Japan in 1992. Graduated in 1962 from the Department of Electrical Engineering Shibaura Institute of Technology and joined Chubu Electric Power Co. in the same year. He is engaged in the development of technology for large-scale centralized control of power systems as well as the networking of control computers. He is currently a System Analysis Group Chief in the System Operation Division of the company. Graduated in 1985 from the Department of Electronics and Electrical Engineering of the Faculty of Engineering Tokyo Institute of Technology and joined Chubu Electric Power Co. in the same year. He is engaged mainly in the development of technology for power system protection and stabilization. He is currently working in the System Analysis Group of the System Operation Division of the company. Toshiba Corporation Graduated in 1967 from the Department of Electrical Engineering University of Tokyo and joined Toshiba Corporation in the same year and engaged in development of power system control systems in Japan and abroad. He is currently a Chief of System Technology in the Power System Technology Division of the company. He is a member of the Theses Subcommittee of the 1995 World Energy Conference. He is an Assistant Secretary of the Japanese Committee of CIGRE and a member of the Japanese Subcommittee of CIGRE SC35 and 39. He is a member of IEEE. Completed his Master's course at the Science and Engineering Research Division of the Graduate School Waseda University in 1980 and joined Toshiba Corporation in the same year. H

A new transient stability controller system (TSC) based on on-line transient stability calculation has been developed. The TSC system prevents the power system from wide-area blackout by shedding generators optimally when a serious fault occurs. This system consists of a central processing unit (TSC-P), and four local units for fault detection (TSC-C), and seventeen units for generator shedding(TSC-T). The TSC-P selects optimal generators to be shed for stabilization based on on-line transient stability calculation for contingencies at 500 kV lines and buses every five minutes. The results are transmitted to the TSC-Cs periodically. Should any fault occur, only one TSC-C will detect the fault occurrence and send control signals to the TSC-Ts which actually generate shedding signals. To realize the TSC system, essential are fast stability evaluation methods for a large number of contingencies and effective selection methods of optimal generators to be shed for stabilization. This paper presents total algorithms applied in the TSC-P, the results of algorithm verification tests using a prototype system combined with a large-scale analog simulator, and the characteristics of the actual system.

关键词： power system stabilization generation shedding on-line stability calculation screening parallel calculation

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