57. Environmentally Adapted Technology for Kaplan Runners

In recent years, especially in the Scandinavian market, focus has been set on reducing the risk for oil pollution from hydropower units. Due to this increased demand from the market, GE Hydro has developed technology for reduction or elimination of the oil quantity inside Kaplan Runner Hubs. A runner hub for a big Kaplan unit with traditional design is filled with large quantities of oil for lubrication purposes. A different technology, Dry sump lubrication, has been developed with the aim to minimize the oil quantity inside the runner hub. In addition measures have been taken to prevent oil leakage through the runner blade seal. In runner hub bottom, a hydraulic pump/motor unit is installed to introduce pressurized oil into the runnber hub for the lubrication of the runner bearings. The oil is then pumped back to the oil circulation system outside the Runner hub. The Runner is also equipped with a special seal arrangement to ensure that oil does not leak out to the waterways, on the contrary water is allowed to leak into the hub. The oil circulation system is equipped with instrumentation for supervision of water content in the oil in order to schedule exchange of Runner Blade seals. The Dry sump lubrication equipment has been installed and is in operation in 5 different Kaplan units since 1999.