Erosion Behaviour of HV of Hard Coatings under Silted-Water Conditions in Vishnuprayag River Hydro Electric Project

Silt erosion of hydro turbines is a widely acknowledged problem in Indian & Chinese hydro power plants. While there is a great potential for hydro power development in India, underwater parts of hydroelectric power stations located in Himalayan region, in general, and run-of-the river schemes located in the northern states of the country, in particular, are prone to severe erosion due to the presence of silt in these water streams. The operation and maintenance of these power stations is indeed a tremendous task and calls for high degree of dedication and motivation on the part of maintenance staff in grappling with the silt related problems. In India, 80% of the available hydro resources are from Himalayan region. This problem further gets aggravated during monsoon season when 98% of the Quartz rich (quartz content generally varies from 70% to 98%) silt particles of size 0.25 mm and smaller (PPM content high: 5000 to 20000) having hardness of 7–8 on Moh’s scale pass through underwater turbine componens. This is a great challenge to the hydro turbine manufacturer to combat this problem. ERDA & Alstom Power Hydro, France have taken long terms initiatives through Alstom hydro Projects India to study the effect of local silt erosion damage as region vise on hydro turbine by carrying out R&D at ERDA, Vadodara. In this paper, the studies carried out on hard surface coatings and 13/4 Cr-Ni steel, their properties and silt erosion characteristics are discussed.