Representative distribution network models for assessing the role of active distribution systems in bulk ancillary services markets

Nowadays, renewable energy sources feed significant shares of energy demand, resulting in a reduction of market energy price but also a significant increase of expenditures for ancillary services due to inherent not complete predictability and programmability. Thus loads and generation in the distribution network are more and more required to play an active role in supporting grid stability by participating to ancillary service markets, either directly or through aggregators. The paper presents a novel procedure to estimate distribution networks capabilities to support grid stability, by making use of synthetic representation of HV/MV substations and their relevant distribution networks with a GIS based clustering procedure. The impact of active distribution networks to the bulk ancillary service market is then evaluated by applications to the Italian electric system and by assuming different regulatory frameworks for transmission/distribution network market interactions.