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175 Computational aspects of distributed state-estimators for power systems
Absu'acts
1079
171 Voltage Collapse Dynamks and Control in a Sample Power System H.O. Wang, E.H. Abed, A.M.A. Hamdan, pp 825-828
state feedback optimal controller is designed for a three-area interconnected power system.
Nonlinear phenomena, including bifurcations, chaos and crises, have been determined to be crucial factors in the inception of voltage collal~e in power-system models. The issue of controlling voltage collapae in the presence of these nonlinear phenomena is addressed in this paper. The work employs an example power system model aldn to one studied in several recent papers. The bifurcation control approach is employed to modify the bifurcations and to suppress chaos and crises. The control law is shown to result in improved performance of the system for a greater range of parameter values.
177 Control of a Flexible Link Hammer for a Hammering Robot T. lzumi, Y. Hitaka, pp 851-854
172 Parallel Self-Tuning Controllers for Turbogenerators B.W. Hogg, G.W. Irwin, M.D. Brown, E. Swidenbank, pp 829-832 The paper describes the practical application of parallel processing for the adaptive control of a laboratory turbogenerator system. A VME system with mmsputers is used to provide a flexible hardware structure, and to achieve fast sampling rates for multiloop and multivariable self-tuning controllers. Experimental results show that improved control may be obtained, and confirm the robustness of the controllers.
173 Distributed Multi-Mode Damping of Power System Oscillations Using SVCs and Remote Measurements G. Lodwich, A.C. Tsoi, pp 833-836 A power system consists of a network of transmission lines connecting multiple generators. Local control of the field current of generators can help damp oscillations but the static vat compensators (SVCs) can be used more directly to reduce system oscillations. In this paper it is shown how the SVC can be controlled to respond primarily to system oscillations using a control based on remote bus angle measurements. It is shown that remote system measurements can produoe superior control to the local feedback of transferred power at each separate SVC location.
174 An Integrated Environment for Operational Planning and Control in Power Distribution Systems C.N. MacQueen, M.R. Irving, M.J.H. Sterling, pp 837. 84O An integrated simulation and analysis environment is .presented which assists distribution system operations engmeers m increasing system utilisation and efficiency. A load-flow-based discrete-time simulator interfaces with a relational plant database, load-modelling software and data from SCADA systems to track the bchaviour of the system with time. Further analysis can be conducted at any time to study fault levels, transient behaviour and the effects of contingencies. Recent developments in X Windows graphics and relational database technology are employed to manage the data efficiently.
175 Computational Aspects of Distributed State-Estimators for Power Systems J.F. Marsh, S. Zltouni, M.R. Irving, pp 841.844 Multi-processor implementations of decomposed static-state estimators for electric power systems are reviewed. The decompositions are computationally efficient, and include distributed forms of bad-data and observability analyses. The computational performance of a multiprocessor solution is influenced by the choice of centralised or distributed architecture, inter-processor communication protocols, and sparsity rogramming. The method has clear computational advantages for rge networks consisting of loosely inter-connected sub-networks. 176 A New LQR Approach to the Design of Power System Stabilizers M. Aldeen, F. Crusca, pp 845.850 In this paper, a systematic approach to the selection of state and control weighting matrices for the linear quadratic regulator problem is presented. This is based on the identification of the most controllable and observable states of the system. While the poorly controllable and/or observable states are ignored, the most controllable and observable states are penefised according to their meamres of combined controllability and observability. A linear
This paper deals with a flexible link for a hammering robot. When a flexible link is rotated by a motor, the head of the hammer vibrates in a complicated manner. The first mode of the vibration is of great use for increasing the hitting velocity and for ab6orbing the reaction from a hit object. The higher modes disturb the hitting velocity and direction. A hammer-driving system has been constituted so as to suppress the higher modes. Some conditions under which the hammer robot can hit an object from a normal direction with a specified normal velocity are taken into consideration.
178 Force.Controlled Robotic Deburrlng M.-H. Liu, H. Tolle, pp 855-858 In this paper a three-step active de.burring strategy is proposed, based on force feedback control. Strategies for automatic c.ontourfollowing have been developed to identify unknown wofkpiece contours, to automatically generate desired robot motions, and to detect unknown burr sizes. Under the active deburring strategy, burr size variations are identified through contour-following and different sizes of burrs are removed with the specification of a variable desired deburring force. Implementation of and experiments with the proposed strategies are described.
179 Autonomous Grasp Control of Link Mechanism by Vibrating Potential Method H. Yokol, Y. Kakazu, pp 859-862 This paper aims at developing a new control method based on a decentralized management approach to describing a mathematical model of autonomous machines, the Vibrating Potential Method (VPM). The VPM draws pandlels with information transmission. The potential functions of each unit are placed on its own harmonic wave as axes. Each unit receives potential energy from the Vibrating Potential Field (VPF) by convolution and determines its own strategy of motion independently. This paper proposes a new control method using fields, and discusses its application to the grasping problem of free-form objects.
180 Integration of Human and Machines In Automatic Opal Processing S. Shoval, A. Cody, E. Froumine, pp 863.866 A system for automatic processing of semi-precions cabochontype gemstones integrates robotics technology, computer vision and human expertise. Each stone is treated individually in order to bring out the best color and brightness. An interactive program allows the operator to quickly and efficiently examine possible combinations of contours for the finished stone, and also offers pre-selected shapes and sizes suitable for calibrated stones. A robotic grinding system pre-shapes and grinds each stone according to the selected geometry. The total processing time is 11.5 minutes (compared with 6-8 minutes when processed manually), and its accuracy is 0.05 m m (compared with 0.2 mm achieved in manual processing).
181 Autonomous Vision-Based Navigation In Buildings R. Frezza, F. Vedana, G. Picci, P. Perona, pp 867-870 This paper addresses the problem of vision-based autonomous navigation inside buildings. The vehicle navigates along an irregular corridor, of unknown shape, characterized by boundaries having a simple piecewise-linear profile. The problem is one of tracking the skirting board of one of the wails of the corridor, while keeping a preset distance from it. The system state consists in the state of the vehicle, aul~mented by a description of the environment. This is sensed using early vision techniques and is modelled as a filtered random walk (as proposed by Dickmanns) augmented with a jump-process to handle environment discontinuities. The scheme is demonstrated and compared to Dickmauns' in extensive simulations.
1079
171 Voltage Collapse Dynamks and Control in a Sample Power System H.O. Wang, E.H. Abed, A.M.A. Hamdan, pp 825-828
state feedback optimal controller is designed for a three-area interconnected power system.
Nonlinear phenomena, including bifurcations, chaos and crises, have been determined to be crucial factors in the inception of voltage collal~e in power-system models. The issue of controlling voltage collapae in the presence of these nonlinear phenomena is addressed in this paper. The work employs an example power system model aldn to one studied in several recent papers. The bifurcation control approach is employed to modify the bifurcations and to suppress chaos and crises. The control law is shown to result in improved performance of the system for a greater range of parameter values.
177 Control of a Flexible Link Hammer for a Hammering Robot T. lzumi, Y. Hitaka, pp 851-854
172 Parallel Self-Tuning Controllers for Turbogenerators B.W. Hogg, G.W. Irwin, M.D. Brown, E. Swidenbank, pp 829-832 The paper describes the practical application of parallel processing for the adaptive control of a laboratory turbogenerator system. A VME system with mmsputers is used to provide a flexible hardware structure, and to achieve fast sampling rates for multiloop and multivariable self-tuning controllers. Experimental results show that improved control may be obtained, and confirm the robustness of the controllers.
173 Distributed Multi-Mode Damping of Power System Oscillations Using SVCs and Remote Measurements G. Lodwich, A.C. Tsoi, pp 833-836 A power system consists of a network of transmission lines connecting multiple generators. Local control of the field current of generators can help damp oscillations but the static vat compensators (SVCs) can be used more directly to reduce system oscillations. In this paper it is shown how the SVC can be controlled to respond primarily to system oscillations using a control based on remote bus angle measurements. It is shown that remote system measurements can produoe superior control to the local feedback of transferred power at each separate SVC location.
174 An Integrated Environment for Operational Planning and Control in Power Distribution Systems C.N. MacQueen, M.R. Irving, M.J.H. Sterling, pp 837. 84O An integrated simulation and analysis environment is .presented which assists distribution system operations engmeers m increasing system utilisation and efficiency. A load-flow-based discrete-time simulator interfaces with a relational plant database, load-modelling software and data from SCADA systems to track the bchaviour of the system with time. Further analysis can be conducted at any time to study fault levels, transient behaviour and the effects of contingencies. Recent developments in X Windows graphics and relational database technology are employed to manage the data efficiently.
175 Computational Aspects of Distributed State-Estimators for Power Systems J.F. Marsh, S. Zltouni, M.R. Irving, pp 841.844 Multi-processor implementations of decomposed static-state estimators for electric power systems are reviewed. The decompositions are computationally efficient, and include distributed forms of bad-data and observability analyses. The computational performance of a multiprocessor solution is influenced by the choice of centralised or distributed architecture, inter-processor communication protocols, and sparsity rogramming. The method has clear computational advantages for rge networks consisting of loosely inter-connected sub-networks. 176 A New LQR Approach to the Design of Power System Stabilizers M. Aldeen, F. Crusca, pp 845.850 In this paper, a systematic approach to the selection of state and control weighting matrices for the linear quadratic regulator problem is presented. This is based on the identification of the most controllable and observable states of the system. While the poorly controllable and/or observable states are ignored, the most controllable and observable states are penefised according to their meamres of combined controllability and observability. A linear
This paper deals with a flexible link for a hammering robot. When a flexible link is rotated by a motor, the head of the hammer vibrates in a complicated manner. The first mode of the vibration is of great use for increasing the hitting velocity and for ab6orbing the reaction from a hit object. The higher modes disturb the hitting velocity and direction. A hammer-driving system has been constituted so as to suppress the higher modes. Some conditions under which the hammer robot can hit an object from a normal direction with a specified normal velocity are taken into consideration.
178 Force.Controlled Robotic Deburrlng M.-H. Liu, H. Tolle, pp 855-858 In this paper a three-step active de.burring strategy is proposed, based on force feedback control. Strategies for automatic c.ontourfollowing have been developed to identify unknown wofkpiece contours, to automatically generate desired robot motions, and to detect unknown burr sizes. Under the active deburring strategy, burr size variations are identified through contour-following and different sizes of burrs are removed with the specification of a variable desired deburring force. Implementation of and experiments with the proposed strategies are described.
179 Autonomous Grasp Control of Link Mechanism by Vibrating Potential Method H. Yokol, Y. Kakazu, pp 859-862 This paper aims at developing a new control method based on a decentralized management approach to describing a mathematical model of autonomous machines, the Vibrating Potential Method (VPM). The VPM draws pandlels with information transmission. The potential functions of each unit are placed on its own harmonic wave as axes. Each unit receives potential energy from the Vibrating Potential Field (VPF) by convolution and determines its own strategy of motion independently. This paper proposes a new control method using fields, and discusses its application to the grasping problem of free-form objects.
180 Integration of Human and Machines In Automatic Opal Processing S. Shoval, A. Cody, E. Froumine, pp 863.866 A system for automatic processing of semi-precions cabochontype gemstones integrates robotics technology, computer vision and human expertise. Each stone is treated individually in order to bring out the best color and brightness. An interactive program allows the operator to quickly and efficiently examine possible combinations of contours for the finished stone, and also offers pre-selected shapes and sizes suitable for calibrated stones. A robotic grinding system pre-shapes and grinds each stone according to the selected geometry. The total processing time is 11.5 minutes (compared with 6-8 minutes when processed manually), and its accuracy is 0.05 m m (compared with 0.2 mm achieved in manual processing).
181 Autonomous Vision-Based Navigation In Buildings R. Frezza, F. Vedana, G. Picci, P. Perona, pp 867-870 This paper addresses the problem of vision-based autonomous navigation inside buildings. The vehicle navigates along an irregular corridor, of unknown shape, characterized by boundaries having a simple piecewise-linear profile. The problem is one of tracking the skirting board of one of the wails of the corridor, while keeping a preset distance from it. The system state consists in the state of the vehicle, aul~mented by a description of the environment. This is sensed using early vision techniques and is modelled as a filtered random walk (as proposed by Dickmanns) augmented with a jump-process to handle environment discontinuities. The scheme is demonstrated and compared to Dickmauns' in extensive simulations.