The master's thesis deals with the process of creating a single-unit model of a hydroelectric power plant. The single-unit model describes the operation of the hydroelectric power plant under different initial conditions and provides values of operational power based on the flow through the hydroelectric plant and the height of the water drop. The decision to use a single-unit model was prompted by its comparative simplicity and fewer variables, in contrast to a two-unit or three-unit model. Consequently, calculations using the single-unit model are more straightforward and efficient. The primary purpose of this model is to facilitate the streamlined control of a series of hydroelectric power plants located along the lower Sava River.
The central aspect of the master's thesis involves computing transfer functions for each individual hydroelectric power plant situated along the lower Sava River. These calculations rely on real hourly average values of flow, operational power, water drop, and water levels obtained from GEN Energija, the company overseeing the power plants. The process of developing the model is explained for each hydroelectric power plant, considering the specific constraints that apply to each of them. Initially, an approximation of the operational power is made for each hydroelectric power plant. Subsequently, transfer equations are formulated for each hydroelectric power plant, with a primary emphasis on capturing the essential characteristics expressed by the hydroelectric plants within the chain. This includes determining the impact of subsequent hydroelectric power plants on the operation of the plant under consideration, as well as the influence of flow on changes in the lower water level and consequently the water drop. The effect of the downstream river channel shape on the coefficients used in the transfer equations is also elaborated upon for each hydroelectric power plant. Furthermore, the thesis briefly describes the unique features and dynamics of the accumulation reservoirs associated with each hydroelectric power plant. The transfer equation for the last hydroelectric power plant in the chain and the influence of downstream river inflow on the rise of the lower water level are also thoroughly analyzed.
In the final section of the thesis, the single - unit models are expressed in matrix form, providing a comprehensive representation of the hydroelectric power plants operations at various operating points. Simulations were also conducted using developed models, and an assessment of the model accuracy was performed at various flow rates of the Sava River. The process of determining the level of the accumulation reservoir, based on the calculated models of the hydroelectric power plants along the lower Sava River, is succinctly explained as well.
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