DISPERSED GENERATION PROVIDING ANCILLARY SERVICES IN DISTRIBUTION NETWORKS THROUGH POWER ELECTRONIC INTERFACES

In the deregulation framework of the energy market, dispersed generation (DG) plays a relevant role being able to provide not only the typical energy service but also ancillary services (e.g., reactive power support, load following, back-up service, and Power Quality (PQ) disturbances compensation) that are of basic importance for both system security and service quality. Ancillary services are easily provided when DG units are interconnected to the distribution network through static converters. Power electronic technology is widely used, e.g.. in the case of wind power generation systems, fuel cells and photovoltaic systems. The converters employed play a vital role in matching the characteristics of the DG units and the requirements of the distribution networks, including frequency, voltage, and control of active and reactive powers etcetera. In fact, converters are characterized by the presence of a control system that provides easily and quickly the required services, maintaining at same time high quality power levels. In this context, the thesis deals with dispersed generation providing ancillary services in electrical distribution systems through power electronic interfaces.