Economic generation dispatch with responsive spinning reserve constraints

The economic reallocation of generation resources to minimize production costs, while maintaining a margin of responsive reserve, is presented. Responsive reserve on units is defined at Houston Lighting & Power Co. (HL&P) to be the minimum of (1) 20% of a unit´s high capability limit, or (2) the adherence between its actual production and the same high limit. By maintaining sufficient responsive reserve across all units, HL&P generation is much more capable of responding to frequency deviations and fast system load pick-up. The algorithm economically reduces generation on lower cost units running at maximum capability to provide room to pick-up load when needed. The algorithm, its integration into the HL&P energy management system and the company´s operating experience in using the techniques are described. Also provided is an analysis of the relatively small economic cost to provide this additional reliability