An appropriate disconnecting time of distributed generation by optimal protection setting and transformer connection type

This paper analyzes the impacts of Distributed Generation (DG) disconnecting time on utility and DG, especially the impact on utility reclosing time. The reclosing time is a temporary interval that a utility protective device is opened after a fault occurrence. Generally, DG must be disconnected before the end of this reclosing time. Mostly, DG may be requested to be disconnected after a fault occurrence instantaneously. However, the latest IEEE 1547.2 Interconnecting Standard recommends that DG shall remain connected in the system for a period of time. This standard causes both advantages and disadvantages for utility and DG. The remaining DG connecting time pay an important role to the consequent impacts on the connected network, especially protection system. Hence, an appropriate DG disconnecting time is investigated in this paper. The solution is achieved by setting Time Dial Setting (TDS), Pickup Current, Terminal Voltage of DG as well as the types of Transformer Connection with Genetic Algorithm (GA).