93. Optimizing Operation of a Low Head Cascade Hydro System Dvekar Dj., Zrinski G., Brezovec M., Pecek D., Mudri Z. (Proceedings, Hydro 2003, Vol. I, Croatia, pp. 227–234). Abstract Cascaded hydro system consisting of 3 hydroelectric power plants on the Drava River in Croatia has been remotely controlled since 1998 from Varazdin Cascaded Hydro System Control Center. Method for hydro system operation comparison before and after Control center establishment was developed, using daily energy production and average daily inflow to evaluate water to energy conversion factor. System operation comparison shows energy production increase and significant advance in a way of hydroelectric power plants control. Additionally, a simple mathematical model of losses at the section between the power houses of Cakovec HPP and Dubrava HPP is developed. Main losses, hydraulic ones in diversion canals and volumetric seepage losses under the storage reservoir embankments, depend on water level in the reservoir – if the level rises, hydraulic losses decrease while volumetric losses increase and vice versa. It is found that when the Dubrava HPP inflow is smaller than 300 m3/s, reservoir level should be aimed to the minimum and at higher inflow to the maximum operating level. Varazdin Cascaded Hydro System Control Center enables quality HPP's remote control and optimization what results in energy production increase. Method for cascaded hydro system operation comparison is realized, and results show remote control and optimization benefits. According to this analysis, water to energy conversion factor increase gained by optimization is about 1.7%. Except this, developed method is also used as a practical checking tool for daily system operation analyses. At the inflow smaller than 300 m3/s, Dubrava HPP reservoir level should be aimed to the minimum operating level. In this way, during run-of-river operation total losses could be decreased up to 0.8 MW. Dependence of the total seepage losses on the reservoir level is determined, for winter and summer period. This will be input data for Control center optimization program. Top Keywords Cascaded hydro system, Hydroelectric power plants, Average daily inflow, Energy conversion factor, Hydraulic losses, Operating level. Top |