Minimum loss predispatch model for hydroelectric power systems

A predispatch model that minimizes generation and transmission losses on hydroelectric power systems is presented and applied to the hydroelectric power system of COPEL, a Brazilian utility located in Southern Brazil. Power loss in the generation and transmission systems is minimized on an hourly basis throughout a day. Load demand as well as generation, transmission and interchange operational constraints are satisfied. Hydroelectric generation characteristics are described in detail. Power loss in hydroelectric generation is associated with a reduction in turbine-generator efficiency and effective water head. The latter is due to an increase in tailrace elevation and penstock head loss. Power loss upon transmission is calculated as a quadratic function of active power flow, as represented in a DC load flow model. The predispatch model was evaluated under typical operational conditions, achieving significant savings with respect to actual operation.