Hydroelectric

The power of water

By tradition Duplomatic is engaged in the sector of renewable energies. After several applications realized in the geothermal sector from the ‘90s onward, the company has recently installed systems for the production of wind energy and solar  thermal energy. Supporting such new technologies, Duplomatic engaged in the hydroelectric sector for the renewal or installation of new hydroelectric power plants.

The successful cooperation with the company Voith Siemens Hydro Power Generation, leader of the sector both in Italy and abroad, led to the installation of tens of Pelton as well as Francis and Kaplan turbines.

The hydraulic systems that power the turbines share a common philosophy as far as power generation is concerned:
■ Two motor-pump groups, one of which is auxiliary to the other
■ System for filtering and conditioning the off-line oil
■ Duplex filter on the common pump delivery
■ Split storage unit for the pump alternation and for the fast handling and safety functions in case of voltage drops.

They differ from each other in terms of solutions adopted for the control circuit and for the drives.

In the Pelton plants a closed loop control is performed both on the penstock (functioning as a nozzle) and the deflector (deviating the water flow) using proportional valves with integrated electronics.

In the Francis turbine the water reaches the runner from an annular channel and the fixed guide vanes direct the flow towards the curved vanes of the runner itself. The regulation of the turbine is achieved by varying the incidence angle of the fixed guide vanes and this function is regulated by hydraulic servoactuators controlled by proportional valves.

The Kaplan turbine uses very low heads with high flow rates. The water reaches the turbine through an annular channel, is then deflected by guide vanes which give an axial direction to the water that finally acts on the runner. By changing the orientation of the runner vanes it is possible to optimize the rotational speeds in relation to the different flow rates, maintaining a high efficiency (around 90%). The hydraulic regulation of the vane angle is obtained by use of proportional valves controlled by position closed loop feedback.

A series of optional hydraulic controls with onoff switches exists for each turbine model which are regularly monitored for the management of upstream and downstream valves and for safety measures.