Hybrid islanding detection method and priority-based load shedding for distribution networks in the presence of DG units

The integration of Distributed Generation (DG) units in the existing power system has made the reliable operation of the system more complex. This has necessitated a comprehensive approach in planning the expansion of the system with the incorporation of DG units for effective and reliable operation of the system. In this study, a robust Hybrid Islanding Detection Technique (HIDT) has been proposed for identifying the islanding event early and accurately in the distribution networks with DGs installed by a two-step Genetic Algorithm (GA) process. As the reliability of power supply to the customer is of utmost importance, a priority-based load shedding scheme is proposed. The proposed load shedding scheme sheds only the vulnerable loads in the island for regaining the frequency and voltage stabilities. By the proposed methods, a comprehensive solution for system planning and emergency control actions can be obtained for effective operation of the system with DG units. The proposed methods are investigated on standard IEEE 33 and 69 bus distribution systems under different loading conditions. The results obtained show that the proposed methods are able to identify the islanding event more effectively and also regain the stability in the island with less amount of load shedding.