Study on islanding detection methods for distributed system

Islanding in power system can be intentional or unintentional. In the past most of the methods were developed for the phenomenon of unintentional islanding. Recently as the distributed generator (DG) sources are able to control voltage and frequency in the islanded part, the phenomenon of unintentional islanded is not common. If the autonomous operation of sources or intentional islanding is desired, then a fast islanding detection technique is necessary. The main philosophy of detecting an islanding situation is to monitor the DG output parameters and system parameters to decide whether or not an islanding situation has occurred from change in the parameters. islanding detection techniques can be classified as remote techniques and local techniques, and local techniques can be divided into passive methods, active methods and hybrid methods. In this paper, several remote and local techniques (passive, active, and hybrid methods) for islanding detection are briefly described. The advantage and limitation of each technique are also introduced. Meanwhile, the comparison of these methods is also discussed.