EXPECTED ENERGY BENEFITS OF VARIABLE SPEED OPERATION OF HYDRO GENERATOR-MOTOR-A CASE STUDY

Abstract

Pumped storage schemes are considered as the proven energy storage schemes in the utility energy storage sector. The role of these schemes in a power system is inevitable for stabilized grid operation. The upcoming technology of variable speed operation helps the system to operate in more efficient way. The latest inventions of power electronics facilitate this operation more flexible and economic. The concept of this technical is the reduction in efficiency due to head variation can be compensated by changing the rotational speed of the machine. This technology has already been adopted in various countries as Japan, Germany successfully. It is found that this technology is more advantageous than conventional pumped storage plant for both generation and pumping. As the life of a hydro power plant is 100 year these benefits compensate the cost of power electronics devices used. This thesis analyses the benefits of the variable speed operation of Tehri pumped storage Plant of India which is the plant having very large head variation. The efficiencies for various head has been extracted from the turbine hill curve, have been utilized for this analysis. The benefits of generation cycle and conventional pumping with part load behavior have been analyzed in detail. The result shows this technology will be useful for the Tehri pumped storage plant economically.