Scheduling of Generation and Reserve Margin Using Dynamic and Linear Programming

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.