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.