RESERVIOR OPERATION PLANNING FOR PROPOSED CASCADE GEBA HYDROPOWER DEVELOPMENT

Abstract

In this study, the main objective is to develop an advanced reservoir operation system for Geba reservoirs with specific objectives of extended flow, developing water balance and preparing a rule curve for Geba reservoirs. The models and the technique which applied for obtaining those objectives was First order Auto-Regressive (AR, 1), Dynamic programming and HEC-ResSim.3 for simulation and optimization of Geba I and II reservoir operation. In order to get the initial guide curve the FORTRAN language of Dynamic Programming (DP) was employed. This initial guide curve was used as starting guide curve during detail reservoir simulation using monthly reservoir inflow data of 32 years. The HEC-ResSim model uses the reservoir physical characteristics (Elevation- Capacity-Area curve), net monthly evaporation from the reservoirs (mm), daily inflow (rrr' /s) operation rule adjusted i.e. tandem operation for Geba I reservoir finally released operation rule for Geba II reservoir, the alternative released guide curve of elevation maximum capacity operation level and maximum elevation relation of dam appurtenant structures such as spillway, penstocks and tail water elevation. The out put of the AR (1) was indicted that the flow which was extended has similar flow pattern with that of the historical recorded flow data. At the same time the DP of FORTRAN language result was represent maximum energy of 135.51GWh during the month July to December and minimum of 4.06GWh during the month of February to April for Geba I reservoir, for Geba II reservoir maximum of 97.99GWh during the month of July to November and minimum of 2.26GWh during the month of February to April. The out put of Tandem operation rule of HEC- ResSim was based on the reservoir water level and the released pattern alternatives; the simulation operation was suggested considering relatively the system minimum losses and maximum power generation of214.5 MW and 157.0MW in