Development of a parallel relief valve synchronized with Francis guidevanes

摘要

The design of a parallel relief valve synchronized with Francis turbine guidevanes was successfully developed and implemented at several powerplants. In the paper, the results for the Rwimi hydro plant are presented. With the installation of a parallel relief valve, transient phenomena have been significantly improved: the pressure fluctuation in the penstock reduces; the closing time of the guidevanes can be shorter; and, consequently, the runaway speed of the generator is reduced. The closing time of the parallel relief valve can be prolonged by up to a few minutes, so the flow stops very slowly. Because of these improvements, the powerplant can operate safely using a cost-effective solution.