Short-term scheduling of a pumped storage plant

The problem is formulated as a mixed-integer nonlinear program where the prices of energy and spinning capacity are assumed known and where two kinds of constraints are considered: first dynamic plant constraints, concerning the operation of several units and including startup costs and minimum up time requirements, and secondly dynamic reservoir constraints, concerning the operation of the upper and lower reservoirs within specified levels. The consideration of dynamic plant constraints together with dynamic reservoir constraints has never been attempted. It is an extended problem and its solution is difficult to approach. Approaches based on dynamic programming, Lagrangian duality and network flow programming are analysed in view of the extended problem and their advantages and disadvantages are indicated. To bridge the gap between the application range of the programming techniques to this problem of pumped storage scheduling, approximate assumptions and a new approach are proposed