Water Hammer analysis of a run-of-river Hydroelectric Power Plant in lower Himalaya: A case study

The term Water Hammer (WH) or hydraulic transients describes the generation, propagation and reflection of pressure waves in the penstock that are associated with sudden changes or alterations in the momentum of fluid conditions. Uncontrolled WH in the penstock may disturb the operation of a hydroelectric power plant. In worst cases, WH events may damage, collapse the penstock and its associated equipments and even cause loss of human life. In this paper, the case study of a run-of-river based hydroelectric power plant is taken for the analysis of the WH in the penstock with or without the use of surge tank. Cost analysis for penstock is also done in both cases. It is shown that without the use of surge tank the required thickness of penstock is increased to encounter the WH pressure, due to which there is an increase in the cost of penstock fabrication. The analyses of WH in penstocks are performed with the closure of guide vanes in the case of sudden load rejections of the turbine or in grid failure condition. The rise of pressure head is computed in penstock within Matlab environment. The maximum surge elevation is also computed in the surge tanks of the power plant.