Protection of micro-grids dominated by distributed generation using solid state converters

The protection of micro-grids containing distributed generation using solid state converters can not depend on monitoring the fault current to detect short circuit faults. In order to protect the semi-conductor devices, the output current from the converter is generally limited to about twice the unit's full load current. This paper describes an alternative and novel approach based on monitoring disturbances in the voltages seen at the generator's terminals to protect the generator and the associated network. It considers the application of this technique to a three-phase network and presents simulation results to a variety of different faults. These demonstrate the operation of the protection scheme and its ability to handle the different types of faults.