KAPLAN TURBINES 2
An important achievement at Newmills Hydro has been the development of a fully
controlled Kaplan turbine. This expedites
policy, (as with standardised Pelton turbines), of minimising on-site assembly.
Subject of course to transport considerations, (which limit the runner size to 2.2metres) the turbine is supplied fully assembled and aligned, up to the power take-off point.
The site works for the Kaplan turbine consist of the draft tube (fabricated in steel or cast in concrete) supplied with a mating flange onto which the turbine is mounted.
The inlet flume can be open or, preferably, a formed concrete volute.
The turbine can then be lowered into position and bolted down.
To assist maintenance a pressure floor plate can be installed above the machine, onto which the gearbox and generator are mounted in order to facilitate easy access.
As stated earlier, hydraulic control is used to supervise the turbine, whereby the runner blades and guide vanes are controlled in unison in order to maximise efficiency and power output.
An auxiliary system (based on storage batteries or hydraulic accumulators), will permit the turbine to be started up in the absence of outside power and, more importantly, to shut down, in the event of overspeed caused by the removal of external load, or by a fault condition.