A CRITICAL STUDY ON DIMENSIONING OF HYDRO POWER STATIONS WITH KAPLAN TURBINE

Abstract

The hydro turbines are defined as the hydraulic machines which. convert hydraulic energy into mechanical energy. This mechanical energy is used in running an electric generator which is directly coupled to the shaft of the turbine. Thus the mechanical energy is converted into electrical energy. In a hydro power station, the hydraulic turbine is the main part, as all the dimensional parameters are dependent upon its dimensions. Therefore, in the planning stage, the dimensioning of the hydro power plant starts with the selection and sizing of the hydro turbine. Before constructing any hydro power plant proper planning is the first step which includes proper analysis of stream flow and. waterpower studies, reservoir levels, location, foundation conditions, determination of capacity, number and size of units and layout and dimensioning of hydro power station. The estimates of cost much depend upon the preliminary planning which decides the scope of the project and forms the basis for decision of its feasibility and for approval of the expenditure of the funds required. After such approval the final design and construction will necessarily follow closely along the line of the general plan in order to remain within the limits of estimated cost. The hydropower stations have very costly electro-mechanical equipments and civil structures therefore it is necessary to be very careful regarding its dimensioning and layout. The preliminary dimensioning and design of hydro power stations starts with power studies which will provide the information on the maximum and minimum heads existing at the site under consideration, average head during a period of low stream flow and desirable total installed capacity at the station. Different combinations of numbers and size of units are to be studied at the initial stage of the planning. Based upon the experiences of previous installations of hydro power projects, preliminary dimensioning of hydro power station is to be carried out. It is very important that the preliminary dimensioning of the power station should be made in such a way that requirements can be met by the manufacturers without much deviation. The selection of the turbines in the overlapping range of Kaplan and Francis turbines through the comparison of installations of different capacity and head has also been done to describe head range governing specific type of turbine, viz. Kaplan or Francis, can be used. XII The present work is an effort to develop and present certain useful guidelines and develop a set of relationships for the Dimensioning of Hydropower Stations with Kaplan Turbines including those for Francis turbines in the overlapping range of head. For this purpose, work done by De Siervo and De Leva, on the Modem Trends in Selecting and Dimensioning of Hydropower Station with Kaplan Turbine, has been extended by collecting data of power stations with Kaplan Turbine in India and have been analyzed to reach at the conclusion.