Intentional islanding operations of distributed generation systems with a load shedding algorithm

Intentional islanding is a condition in which a distributed generation source continues to supply power to the local loads during a catastrophic utility failure. With a properly coordinated and sophisticated control scheme, islanding can be a possible solution, to ensure reliable power to the critical loads. This paper analyzes a control scheme for intentional islanding operation of an inverter based DG system. In grid connected mode, the interface control is designed to provide constant active and reactive power to the load. When grid is disconnected, an islanding detection algorithm will transfer the inverter into voltage control mode. The mismatch between load and generation is removed by implementing a load shedding algorithm. This paper also investigates the performance and the Non Detection Zones of the islanding detection scheme with different interface controllers.