Variable Speed Small Hydro Plant Connected to Power Grid or Isolated Loads

Small size hydro plants are commonly constituted of fixed speed drives. To allow extended control features for these sources in order to integrate them into the energy grid, an autonomous variable speed doubly fed induction generator (DFIG) based source is proposed. Modelling process of the DFIG is described ; it leads to an unified control strategy for operation on a power grid or isolated loads. Transition from grid connected mode to isolated one is discussed.