Ancillary services provision in terminal distribution systems

In this article, the Ancillary Services (AS) to be provided by Distributed Renewable Energy Sources (DRES) located within Distribution Systems (DSs) are presented in detail. These AS are provided in a coordinated and aggregated manner from the DRES to the DSs. Some AS are related to the quality of supply within DSs, while other AS are offered to the Transmission Systems (TSs) to assure the frequency stability following a bottom-up approach: from DRES to the DSs and from DSs to the upstream TS. Finally, the main components toward the transformation of the AS into tradable quantities are analyzed, so that even the smallest DRES owners can participate in respective markets.