Temporary islanded operation of dispersed generation on distribution networks

The use of decentralized electrical energy resources may be a useful support to the main power supply. In particular, in the event of an upstream supply outage, the temporary islanding operation of dispersed generators in distribution networks might greatly improve the quality and continuity of the power supply. The aim of this work is to verify the feasibility of temporary grid-disconnected operation of autonomous portions of distribution networks that use embedded generators. The analysis focuses on the critical transients occurring at disconnection from and reclosure with the main supply. A realistic distribution network model with both rotating and static embedded generators has been considered. Suitable P-and V-f control schemes for static generators have been developed, making it possible to operate in both grid-connected and island modes. The simulation results show that the presence of static (or inverter interfaced) generators with suitable control schemes may greatly improve the steady-state as well as transient performance of the islanded generation park.