Variable Speed Operation of a New Very Low Head Hydro Turbine with Low Environmental Impact

While large and medium head hydro projects and technology have been intensively developed during the last decades, low head sites have been generally neglected due to the cost of civil work making such projects non-profitable. A new very low head turbine has been especially developed to address those sites. Keeping projects profitability at a good level was made possible by reducing required civil work and keeping the turbine as simple and as standard as possible. Control and efficiency issues have been addressed by using state of the art power electronics to achieve the best output at low head. This article gives an overview of the turbine design and its control technique using practical results measured on a first 450 kW unit installed and commissioned in southern France during spring 2007 and running since then.