Development of a logical rule-based islanding detection method for distributed resources

The islanding protection for distributed resources (DR) becomes an important and emerging issue in power system protection since the distributed resources installations are rapidly increasing and most of the installed systems are interconnected with distribution network. In order to avoid the negative impacts from islanding operations of DR to protection, operation, and management of distribution system, it is necessary to effectively detect the islanding operations of DR and disconnect it from distribution network rapidly. Generally, it is difficult to detect islanding operation by monitoring only single system parameter. This paper presents a new logic based islanding detection algorithm for distributed resources that is interconnected with distribution network. The proposed islanding detection algorithm utilizes four system parameters that include the conventionally used ones of voltage magnitude, phase, and frequency and the newly proposed one in this paper of total harmonic distortion (THD) of current. The method monitors changes in four parameters and detects the islanding operations by logical rules. The authors verified the efficiency of the proposed method using the radial distribution network of IEEE 34 bus model.