OPTIMAL SHORT-TERM SCHEDULING FOR A LARGE-SCALE CASCADED HYDRO SYSTEM

This paper describes a short term hydro generation optimization progra m that has been developed by the Hydro Electric Commission (HEC) to de termine optimal generation schedules and to investigate export and imp ort capabilities of the Tasmanian system under a proposed DC interconn ection with mainland Australia. The optimal hydro scheduling problem i s formulated as a large scale linear programming algorithm and is solv ed using a commercially-available linear programming package. The sele cted objective function requires minimization of the value of energy u sed by turbines and spilled during the study period. Alternative formu lations of the objective function are also discussed. The system model incorporates the following elements: hydro station (turbine efficienc y, turbine flow limits, penstock head losses, tailrace elevation and g enerator losses), hydro system (reservoirs and hydro network: active v olume, spillway flow, flow between reservoirs and travel time), and ot her models including thermal plant and DC link. A valuable by-product of the linear programming solution is system and unit incremental cost s which may be used for interchange scheduling and short-term generati on dispatch.