A Novel Load Shedding Strategy for Distribution Systems with Distributed Generations

Frequency stability is one of the key targets needed when an islanding operation occurring in a distribution system or a microgrid. To balance the generation and demand all the time, load shedding may need to apply to a distribution system or a microgrid which disconnected from the main grid. However, it is difficult to determine the accurate amount of load to be reduced in a real system, as the frequency is changing all the time. In addition to this, economic factors including reliability index and consumers' willingness need to be taken into accounted when making the decision except ensuring system stability. This paper proposes a novel load shedding strategy by considering power stability with economy in load shedding for a distribution system with distributed generations such as CHP, small wind and solar panels. The proposed strategy by classifying load into heavy and light groups is adopted, ranking is based on willingness to pay, frequency threshold and rate of change of frequency (RoCoF). The proposed method is applied to a low voltage distribution 33-bus system and the simulation was carried out with DIgSILENT.