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108 Extended generation control and dispatch
560
Abstracts
103 Integration of Transformers with Voltage Regulation into an Optimal Power Flow Algorithm for the VEW HV and EHV Grid P. Steizner, H.-J. Haubrich, D. Heinz, pp 311-316 When introducing an Optimal Power Flow algorithm in the control centre of the German utility VEW it had to be considered that all transformers feeding the ll0kV voltage level are equipped with local voltage regulators. The paper deals with the modelling of those decentralized voltage regulators and their integration into an existing optimal power flow algorithm developed at the Aachen University of Technology. The main results achieved by application of the extended Optimal Power Flow algorithm to the VEW HV and EHV grid are presented.
104 Decentralized Secondary Voltage Control and Pilot Bus Selection T. G6mez, A. ConeJo, J. I. de la Fuente, F. L. Pagola, C. J. Rehn, pp 317-323 The aim of the secondary voltage control is to maintain voltage magnitudes of several load buses, selected as pilot buses, at optimal values imposed by the tertiary voltage control. This paper presents a comprehensive formulation of the secondary voltage control. Centralized control matrices for an optimal proportional integral control are obtained by the minimization of a performance index. Conditions to achieve a stable closed loop in a decentralized control scheme, and a systematic methodology for selecting pilot buses and for dividing the system into decentralized control areas are presented. The differences between centralized and decentralized control schemes are analyzed in a case study.
western European system, and an attempt is made towards a better understanding and coordination of voltage control.
107 Co-Ordinated Controller for a Static VAR Compensator/Synchronous Generator System B.W. Hogg, A.R. Mahran, A.M. Serag, S.M. Sharaf, pp 335-340 This paper presents a new control approach for designing a coordinated controller for a synchronous generator excitation and static VAR compensator system. The objective is to extend the operational margins of stability, whilst satisfying control requirements, by introducing an integrated multi-variable controller. The system dynamics are modelled using unbiased recursive least squares identification. The synthesis of a co-ordinated optimal controller is achieved by minimizing a quadratic performance index using dynamic programming techniques. This avoids the difficulties arising in coordination of static VAR compensator and synchronous generator controllers. System behaviour under transient conditions is assessed. 108 Extended Generation Control and Dispatch G. Schwar'z, H. Hafner, pp 341-346 An advanced software system for Generation Control and Dispatch is presented. It is based on well-tuned coordination of the components Automatic Generation
Control, Economic Dispatch and Reserve Monitoring. The features of these components, and their interactions, are described. In cases where network transport restrictions have to be regarded, an optimal power flow can be incorporated.
105 Modeling of the Voltage-Reactive Power Behaviour of Large-Scale Power Systems - Process Aggregation and Simulation Model J. Uhllg, H.-H. Wilfert, B. Haufe, Ch. Hoy, K. KfiBner, H.-H. Marschner pp 325-330
109 Hydro Coordination in an Energy Management
The investigation of voltage/reactive power phenomena in large-scale power systems and the development of improved voltage-control strategies require rather sophisticated simulation models, so that margins of power transmission and system limitations of real systems are correctly reproduced. For a large system this modeling has to be done as a compromise between the necessary aggregation of parts of the complete system model and the model accuracy. An engineering-based methodology for such a modeling of the voltage/reactive power behaviour of large power systems is described. The resulting simulation model allows the realization of the usual voltage commands and allows detailed operating studies of voltage problems.
Coordination of hydro resources over the yearly operational planning period is a challenging mathematical optimization problem. The application of this operational planning strategy through weekly, hourly, and real-time scheduling of hydro units further increases the complexity of the problem. A hierarchical scheduling scheme is proposed for a computer-based water management system (WMS), to translate the yearly strategy meaningfully into weekly and real-time decisions. The WMS is decomposed into the major functional units of yearly and weekly hydro schedules, real-time scheduling and control, and water use monitor. The paper addresses the problems associated with each function, and the coordination of these functional units in an EMS.
106 A Step Towards a Better Coordination of the Voltage Control Between Different Countries: Results of a Structural Analysis on a Part of the Western European Power System C. Vialas, E. Miconnet, E. Amthauer, pp 331-334
110 The Application of Deterministic and Probabilistic Methodologies to Spinning Reserve Policy in Thermal Generation Scheduling
Controlling the voltage profile in areas near borders between countries and utilities is a difficult issue, possibly because of specific rules of operation due to different network characteristics or material constraints determining the acceptable voltage. This paper defines "natural" voltage control zones for a part of the western European power system, using a hierarchical classification algorithm. As these zones are determined by electrical distances they do not normally match the borders between countries or utilities. The voltage control zones are subsequently compared with an actual voltage profile in the centre of the
This paper presents a new approach to determine the optimal spinning reserve policy in thermal generation scheduling. Production costs and customer's outage cost are included by applying both deterministic and probabilistic methods. The former is used to find the optimum generation schedule. Next, the probabilistic method is applied to calculate the utility's costs, together with the customer's outage cost. The optimum spinning reserve policy can be found, with the best compromise between the utility's costs and the customer unserved energy cost. It can be applied in generation scheduling while the familiar deterministic method is still
System S. Vemuri, W.J. Hobbs, L. Lemonidls, pp 347-350
B. Eua-Arporn, B.J. Cory, pp 351-356
Abstracts
103 Integration of Transformers with Voltage Regulation into an Optimal Power Flow Algorithm for the VEW HV and EHV Grid P. Steizner, H.-J. Haubrich, D. Heinz, pp 311-316 When introducing an Optimal Power Flow algorithm in the control centre of the German utility VEW it had to be considered that all transformers feeding the ll0kV voltage level are equipped with local voltage regulators. The paper deals with the modelling of those decentralized voltage regulators and their integration into an existing optimal power flow algorithm developed at the Aachen University of Technology. The main results achieved by application of the extended Optimal Power Flow algorithm to the VEW HV and EHV grid are presented.
104 Decentralized Secondary Voltage Control and Pilot Bus Selection T. G6mez, A. ConeJo, J. I. de la Fuente, F. L. Pagola, C. J. Rehn, pp 317-323 The aim of the secondary voltage control is to maintain voltage magnitudes of several load buses, selected as pilot buses, at optimal values imposed by the tertiary voltage control. This paper presents a comprehensive formulation of the secondary voltage control. Centralized control matrices for an optimal proportional integral control are obtained by the minimization of a performance index. Conditions to achieve a stable closed loop in a decentralized control scheme, and a systematic methodology for selecting pilot buses and for dividing the system into decentralized control areas are presented. The differences between centralized and decentralized control schemes are analyzed in a case study.
western European system, and an attempt is made towards a better understanding and coordination of voltage control.
107 Co-Ordinated Controller for a Static VAR Compensator/Synchronous Generator System B.W. Hogg, A.R. Mahran, A.M. Serag, S.M. Sharaf, pp 335-340 This paper presents a new control approach for designing a coordinated controller for a synchronous generator excitation and static VAR compensator system. The objective is to extend the operational margins of stability, whilst satisfying control requirements, by introducing an integrated multi-variable controller. The system dynamics are modelled using unbiased recursive least squares identification. The synthesis of a co-ordinated optimal controller is achieved by minimizing a quadratic performance index using dynamic programming techniques. This avoids the difficulties arising in coordination of static VAR compensator and synchronous generator controllers. System behaviour under transient conditions is assessed. 108 Extended Generation Control and Dispatch G. Schwar'z, H. Hafner, pp 341-346 An advanced software system for Generation Control and Dispatch is presented. It is based on well-tuned coordination of the components Automatic Generation
Control, Economic Dispatch and Reserve Monitoring. The features of these components, and their interactions, are described. In cases where network transport restrictions have to be regarded, an optimal power flow can be incorporated.
105 Modeling of the Voltage-Reactive Power Behaviour of Large-Scale Power Systems - Process Aggregation and Simulation Model J. Uhllg, H.-H. Wilfert, B. Haufe, Ch. Hoy, K. KfiBner, H.-H. Marschner pp 325-330
109 Hydro Coordination in an Energy Management
The investigation of voltage/reactive power phenomena in large-scale power systems and the development of improved voltage-control strategies require rather sophisticated simulation models, so that margins of power transmission and system limitations of real systems are correctly reproduced. For a large system this modeling has to be done as a compromise between the necessary aggregation of parts of the complete system model and the model accuracy. An engineering-based methodology for such a modeling of the voltage/reactive power behaviour of large power systems is described. The resulting simulation model allows the realization of the usual voltage commands and allows detailed operating studies of voltage problems.
Coordination of hydro resources over the yearly operational planning period is a challenging mathematical optimization problem. The application of this operational planning strategy through weekly, hourly, and real-time scheduling of hydro units further increases the complexity of the problem. A hierarchical scheduling scheme is proposed for a computer-based water management system (WMS), to translate the yearly strategy meaningfully into weekly and real-time decisions. The WMS is decomposed into the major functional units of yearly and weekly hydro schedules, real-time scheduling and control, and water use monitor. The paper addresses the problems associated with each function, and the coordination of these functional units in an EMS.
106 A Step Towards a Better Coordination of the Voltage Control Between Different Countries: Results of a Structural Analysis on a Part of the Western European Power System C. Vialas, E. Miconnet, E. Amthauer, pp 331-334
110 The Application of Deterministic and Probabilistic Methodologies to Spinning Reserve Policy in Thermal Generation Scheduling
Controlling the voltage profile in areas near borders between countries and utilities is a difficult issue, possibly because of specific rules of operation due to different network characteristics or material constraints determining the acceptable voltage. This paper defines "natural" voltage control zones for a part of the western European power system, using a hierarchical classification algorithm. As these zones are determined by electrical distances they do not normally match the borders between countries or utilities. The voltage control zones are subsequently compared with an actual voltage profile in the centre of the
This paper presents a new approach to determine the optimal spinning reserve policy in thermal generation scheduling. Production costs and customer's outage cost are included by applying both deterministic and probabilistic methods. The former is used to find the optimum generation schedule. Next, the probabilistic method is applied to calculate the utility's costs, together with the customer's outage cost. The optimum spinning reserve policy can be found, with the best compromise between the utility's costs and the customer unserved energy cost. It can be applied in generation scheduling while the familiar deterministic method is still
System S. Vemuri, W.J. Hobbs, L. Lemonidls, pp 347-350
B. Eua-Arporn, B.J. Cory, pp 351-356