PARALLEL OPERATION OF GRID CONNECTED PERMANENT MAGNET SYNCHRONOUS GENERATORS FOR SMALL HYDROPOWER PLANTS

Abstract

In order to make the utilization of hydropower more efficient and economical, VA Tech Hydro, Austria has completed the development process of a new type of turbine generator coupled system called HydroMatrix. Recently it did further refinement to this HydroMatrix technology in the form of StrafloMatrix. The HydroMatrix consists of a factory assembled mesh or matrix of small propeller turbine — generator units. A prototype of 500 kW matrix turbine unit has been built with induction generators and a matrix turbine is currently running under test conditions. In order to further develop the StrafloMatrix which operates synchronously with the grid system, the synchronous generators can be considered as the high efficiency alternative for the conventional induction generators. The recent development in the permanent magnet technology encourages the use of the permanent magnets for the excitation of the rotor instead of conventional electrically excited field windings of the rotor. Also the generator is proposed to have the damper cylinder in order to quickly damp the oscillations caused by sudden switching, load changes, under symmetrical or unsymmetrical fault conditions. This damper cylinder also helps in providing the asynchronous start to the synchronous machine. As all generators in the matrix configuration are arranged in parallel to sum up their individual loads before feeding to the grid, the parallel operation of grid connected permanent magnet synchronous generators with damper cage is studied. This is done by building a model for the single permanent magnet synchronous machine with damper cage using MATLAB/simulink and verifying its accuracy through analytical calculations.