Showing papers on "Economic dispatch published in 1981"

Optimal Control of Reactive Power flow for Improvements in Voltage Profiles and for Real Power Loss Minimization

Abstract: A mathematical formulation of the optimal reactive power control (optimal VAR control) problem and results from tests of the algorithm are presented in this paper. The model minimizes the real power losses in the system. The constraints include the reactive power limits of the generators, limits on the load bus voltages, and the operating limits of the control variables, i.e., the transformer tap positions, generator terminal voltages and switchable reactive power sources. Real power economic dispatch is accomplished by standard techniques.

Constrained Economic Dispatch of Multi-Area Systems Using the Dantzig-Wolfe Decomposition Principle

Abstract: The economic dispatch problem with constraints on line flows and spinning reserve is formulated as a linear optimization program. Such a linear program is then solved using the Dantzig-Wolfe decomposition principle. The sub-programs of the decomposition may correspond to physical areas of the power network, and are individually solved employing the revised simplex method with upper bounds. A fast decoupled load flow algorithm is used to calculate penalty and sensitivity factors. Several illustrative examples are included.

Scheduling of Generation and Reserve Margin Using Dynamic and Linear Programming

Abstract: It has become common practice to schedule generation over time by using dynamic programming techniques that compare the economic dispatch of different combinations of generating units at one hour intervals. Recently, a linear programming technique for economic dispatch has been developed that optimally dispatches generation such that reserve margins and ramp rate constraints are also met at minimum cost. This paper presents a method that combines these dynamic and linear programming techniques such that the real operational constraints of reserve margins and ramp rates are optimally met by the resulting generation schedules. A major advantage of this method is that it can be used to determine the minimum cost of providing a particular level of reserves or operating with a particular set of ramp rate capabilities. Such a costing method makes it feasible to make economic decisions on whether to buy or sell regulation or spinning margin, or whether to install new ramping capability. The algorithm, program design, and the results for a large midwestern utility are presented.

Economic Fuel Dispatch

Abstract: The economical use of all types of fuels available for the generation of power has become a major concern of electric utilities. Present methods do not fully take advantage of standard economic load dispatch minimization techniques because the fuel constraints on each type of fuel are not considered-in the classical calculation. Presented herein is a minimization technique that includes the standard load constraints as well as the applicable fuel constraints. The technique is as it would be applied to real-time control of a power system participating in short-term fuel management by automatic means.

Economic Dispatch Reserve Allocation

Abstract: In this paper, the economic dispatch problem is reformulated to include a constraint on the maximum average system frequency deviation of a power system following a postulated disturbance. The economic dispatch problem is translated into a well-defined nonlinear mathematical programming problem whose solution is obtained by solving a sequence of linear programming problems. Test results on a 20-node power system to demonstrate the improvement in the post-disturbance maximum average system frequency deviation and the relative trade-off in generation costs are included.

Constrained Economic Dispatch of Multi-Area Systems Using the Dantzig-Wolfe Decomposition

Abstract: The economic dispatch problem with constraints on line flows and spinning reserve is formulated as a linear optimization program. Such a linear program is then solved using the Dantzig-Wolfe decomposition principle. The sub-programs of the decomposition may correspond to physical areas of the power network, and are individually solved employing the revised simplex method with upper bounds. A fast decoupled load flow algorithm is used to calculate penalty and sensitivity factors. Several illustrative examples are included.

Cost-Benefit Justification of an Energy Control Center

Abstract: Today there is no accepted methodology for evaluating the economic worth or the cost-effectiveness of Energy Management System functions which are intended to enhance the " security" of a power system. This paper reports on a study which analyzes the improvement in system reliability obtained from a sophisticated security analysis and security dispatch system. The worth of these functions is evaluated in terms of the additional transmission expansion required over a period of years in order to maintain system reliability with and without the security dispatch system. Significant economic results are obtained; also, the relative effectiveness of sophisticated and rigorous techniques versus manual or simple approaches is demonstrated.

A dynamic model of power system operation incorporating load control

Abstract: Load management, which involves tailoring electric energy use to match electric energy supply, has been frequently suggested as an alternative for increasing the efficiency of the electric energy system. However, traditional utility analysis tools are frequently inadequate for assessing the costs and benefits of alternative load management options. One such problem is the consideration of active utility load control in the unit commitment/ economic dispatch problem. A model has been developed to determine how a power system with an active load control system should be operated to make the best use of its available resources. The model uses a dynamic programming successive approximation technique called gradient dynamic programming developed during the project to solve this control problem for realistically sized systems. The development of the model and its computer implementation are presented. The use of the model is demonstrated on several case studies of current interest. The case study results indicate that the production cost savings that can be achieved through the use of direct load control are highly dependent on utility characteristics, load characteristics, storage capacity, and penetration.

A Computer Controlled Laboratory Model of a Three-Area, Tieline Power Flow System

Abstract: A laboratory model of a three-area tieline power flow system is described in this paper. A DEC 11/03 minicomputer and three Motorola M6800 microprocessors are used to acquire data and control tieline power flow. Algorithms are presented that implement data acquisition and permit various control strategies. Student interest in the Power Systems - Machinery Laboratory is greatly enhanced with this model and its related computer-controlled design projects, and this interest continues with further model development of economic dispatch, stability and fault analysis and other area control problems.

INCORPORATING UlAD CONTROL

Abstract: Load management, which involves tailoring electric energy use to match electric energy supply, has been frequently suggested as an alternative for increasing the efficiency of the electric energy system. However, traditional utility analysis tools are frequently inadequate for assessing the costs and benefits of alternative load management options. One such problem is the consideration of active utility load control in the unit commitment/ economic dispatch problem. A model has been developed to determine how a power system with an active load control system should be operated to make the best use of its available resources. The model uses a dynamic programming successive approximation technique called gradient dynamic programming developed during the project to solve this control problem for realistically sized systems. The development of the model and its computer implementation are presented. The use of the model is demonstrated on several case studies of current interest. The case study results indicate that the production cost savings that can be achieved through the use of direct load control are highly dependent on utility characteristics, load charac