PIECEWISE LINEAR FUNCTIONS APPLIED TO RESERVOIR OPERATION RULES FOR POWER SYSTEM PLANNING

The planning and operation of large-scale power systems with a significant share of renewable energy sources, such as hydroelectric plants, require the consideration of complex factors, including hydrological uncertainty and operating constraints. In the face of the severe water scarcity in the Brazilian National Interconnected System (SIN) in recent years, the local agencies implemented operating rules to prevent critical reservoir levels and enhance water security, mainly in the Paraíba do Sul and São Francisco basins. This paper introduces a methodology for incorporating these rules as linear constraints through interpolation in computational simulations using the Stochastic Dual Dynamic Programming (SDDP) algorithm. The results in the SIN case study highlight the methodology's effectiveness in maintaining reservoir levels above critical thresholds even in scenarios of low water availability. This approach provides valuable insights for planning and operating power systems with a high share of renewable energy sources and complex operating constraints.