New approaches to load shedding problem in islanding situation in distribution networks with distributed generation

In electric power distribution systems with dispersed generation (DG), it is common to trip DG units in case of a sudden outage of a large generation unit. In new scenarios of operation of electric power systems keeping the DG units in an islanded distribution system is preferred. Load shedding is one of the most important measures in such distribution system that can be used to achieve this goal, but in fact it is the last chance for preventing a system blackout. In this paper, the frequency of the centre of inertia (COI) is proposed in an adaptive load shedding scheme. The proposed technique does not require communication between the components and real time system data; rather, it uses loads histories to shed the loads automatically with declining frequency.