New energy for your hydro power plant

Ansaldo Sistemi Industriali designed a new solution for the revamping of mini-hydro plants

Nowadays the hydroelectric generation is the most important renewable energy source in the world, as it covers 20% of the entire production of electricity.
Small plants, both of the run-of-river and of the gravity type, are those most invested in, as they present two relevant characteristics: low management costs and low environmental impact. Thus the intensification of hydroelectric resources will continue in this direction, paying attention to the small fluctuations that have been disregarded up to now, to the extension of existing plants and even the exploitation of small aqueducts.
For these type of plants Ansaldo Sistemi Industriali designed an innovative permanent magnet (PM) generator solution. In this new solution, the generators are directly coupled to the hydraulic turbine (without multiplying gears, elimination of oil and loss of power) and the rotational speed is coordinated at each moment to the angle of attack of the impeller blades, according to the available head. In this way the efficiency of the turbine - and of the whole conversion chain - is set to the maximum levels in any conditions of tide and water flow rate. Subsequently the productivity increases and the return on investment time decreases.
The permanent-magnet generators developed by ASI are dimensioned for a speed of 700 rpm with a 1000V isolation and have been tailored to the torque and speed requirements and to the constraints imposed by the turbines. For example, in those cases where the availability of flowing water is high, the PM generators are cooled with fluid through a casing in which the same liquid used for removing leakages from the converter is pushed, they operate on a tilted axis and have a drilled rotor allowing the passage of the impeller blade angle control rod. The PM generators are connected to LV or MV inverters and the converted power is directed towards the network through active front end: state of the art generator technology and special power electronic solutions for better performances at variable conditions to maximize renewable energy power.