Stability of a MV distribution network with electronically interfaced distributed generation

This paper studies the influence and potential benefits of an electronically interfaced distributed generator with respect to overall network behavior and under varying load conditions. A fuel cell (FC) generator has been chosen to represent distributed generation technology of relatively high efficiency, low environmental impact and good dynamic response during disturbances. Several operational modes of a fuel-cell generator corresponding to different control strategies of its inverter interface are investigated. The new control scheme of a power conditioning unit (PCU) is proposed and its performance tested with respect to network security and stability. The results suggest that an adequately designed PCU can not only contribute to the system voltage and frequency control but also alleviate potential instability problems and extend stability region during heavy loading conditions.