Highly Efficient Renewal of A Hydropower Plant Pipe Coating

Abstract

Many pumped storage hydropower plants have long large diameter steep steel pipes (penstocks) between reservoirs. The coating inside such pipes protects the surface from corrosion. Lifetime of the coating is limited and it has to be renewed several times during expected lifetime of the hydropower plant. The coating renovation was a manual process until now. A modification of the process is proposed. The modification of the process includes changes in the technological steps as well robotization of these steps. The new process provides more stability in the quality of coating and eliminates unnecessary presence of people in confined spaces. Using a robot also makes the renewal of the coating much faster. Therefore, it can bring a lot of profit to the owner by shortening the production downtime and re-starting production significantly earlier in comparison to the existing renovation process. The new process was verified in a pilot project at a selected pumped storage hydropower plant and the results were evaluated in cooperation with the hydropower plant owner. Laboratory tests of samples have shown that the coating has two times higher adhesion to the substrate in comparison to the manual coating application. The results also showed that the owner can save around 600 days of downtime on each of both penstocks when using this new process. This is a clear economical advantage which each owner of the infrastructure can understand easily.