Primary Frequency Control in an Ancillary Services Market in Real Time and its Relationship with Solar-Wind Generation

Abstract

In Chile, the operation and market of renewable solar-wind generation and conventional gas-coal-diesel-hydraulic generation is made up of two electric generation systems that are managed in a complementary manner and currently interconnected under the name of “Sistema Eléctrico Nacional”, counting on the greatest potential and solar development in South America. However, the real-time operation is carried out by the Dispatch and Control Center, which treats them as two independent electrical generation systems in terms of supervision and control. The system faces the challenge associated with the massive potential and development of solar-wind generation concentrated in the northern area of Chile. This creates difficulties in its technical operation, especially in frequency control and the complexity of modeling in real-time the changing market for complementary services. Therefore, the primary frequency control is the complementary service that acts as the first action and line of defense to allow the system to integrate large blocks of renewable energy. It is necessary to deliver a minimum of dynamic reserves in times of ten seconds and five minutes to avoid the operation of stages of load disconnection/generation due to low/over frequency in front of large power disconnections of gas-fired plants (520 MW), hydraulic of reservoir (700 MW) and coal (380 MW) or loss of demand from large mining processes (300, 500 and 600 MW) for systemic frequency variations that should not exceed±0.7 [Hz].