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Over 75% of domestic electric power consumption in Colombia is supplied by hydropower. Abrasive wear is degrading turbine components such as Pelton needle valve nozzles. This problem has been studied on the components themselves (in situ). However, it was necessary reproduce the same hydro-abrasive phenomena in a controlled laboratory environment. This study describes the design and construction of a test rig capable of replicating the same wear mechanism present in Pelton needle valve nozzles at Chivor hydroelectric plant. The development of the test rig allowed to conduct empirical testing for the comparison of the plasma nitriding process versus the WC-Co-Cr coat deposited by HVOF to extend the lifetime of the nozzle. Both processes showed significant improvement in hardness and wear resistance compared to the original material specification of the needle valves. [ABSTRACT FROM AUTHOR]

This work presents an assessment of the potential use of hydrokinetic turbines in the discharge channels of large hydroelectric power plants in Colombia. The assessment is performed at a pre-feasibility stage in order to evaluate the technical and financial potential of using hydrokinetic devices as a way to exploit kinetic energy in such channels. As a case study, two large hydropower plants were selected, one operated by a Francis turbine and the other operated by a Pelton turbine. The analysis assessed the hydraulic characteristics of the channels and the corresponding discharge flows. A prefeasibility financial analysis in an environment of uncertainty was also carried out using Monte Carlo simulation. The results show that the technology is not currently feasible for the Colombian market conditions, but the situation should be monitored in order to identify the right time for its optimal use in the future. The proposed methodology can be applied to research the feasibility of hydrokinetic energy for other kinds of applications. [ABSTRACT FROM AUTHOR]