Technical-Economic Model in the Real-Time Ancillary Services Market for the Reallocation of Power Reserves in Primary Frequency Control

Chile’s National Electric System is one of the countries in South America with the greatest potential for the development of solar–wind generation, allowing for the acceleration of the energy transition with the definitive withdrawal of conventional fossil fuel thermal generation. However, the integration of the market of ancillary services requires security, stability, and quality of service to the electricity system. In this context, the primary frequency control (PFC) is considered as the first line of defense of an electric power system, due to its immediate action in severe frequency variations when they exceed ±0.7 Hz with respect to the nominal operating frequency of 50.00 Hz, allowing the safe and efficient integration of large blocks of solar–wind renewable generation in spite of the uncertainty or forecast errors that could cause its massive dispatch. The principal contribution of this work is the implementation of a technical-economic mathematical model that minimizes the total costs of real-time power reserve reallocations for primary frequency control, using the dynamic factors of stationarity in those conventional and renewable solar–wind generation plants. The validation of the model is consolidated through real scenarios, specifically the deficit of power reserves, which necessitates a dynamic response in primary frequency control over 10 s and 5 min. In terms of expected results, the proposed model contributes to the Supra-/Infra-Marginal methodology, reducing the total costs of power reallocation reserves for primary frequency control, compared to other inefficient methods, such as the Maximum Power Method, the Minimum Technical Method, and the Random Direct Instruction Method.