ABSTRACT The flexibility provided by distributed energy resources and demand response can increase the capacity of existing distribution networks to accommodate renewable energy generation and new high‐peak/coincident loads. However, the use of flexibility in providing local services to distribution system operators can limit the availability of flexibility for system ancillary services, which are necessary for the transmission system operator to ensure security and adequacy. Since flexibility is not infinite, the competition between the system operators will increase with the progression of the energy transition. The same interaction appears between medium‐voltage and low‐voltage grids, for instance, when smaller distribution system operators are supplied by medium‐voltage distribution networks operated by a different distribution system operator. The secondary substation, the interface between the medium‐voltage and the low‐voltage, can provide ancillary services by changing its working point to keep the operation of the medium‐voltage network within technical boundaries. Forecasting the secondary substation behaviour is not straightforward due to the lack of information on low‐voltage networks and generation/consumption patterns. The paper proposes a methodology to estimate and forecast the flexibility that low‐voltage distribution networks can provide, even when detailed data about these networks is missing. The proposed method combines the geospatial forecasting, useful for estimating demand, generation, and resource distribution using geographic and demographic data; the synthetic low‐voltage network modelling, for creating realistic network models when detailed data is unavailable; and the flexibility estimation at the secondary substation for determining how its operating point can be adjusted to provide services to the medium‐voltage grid while complying with the low‐voltage network constraints. The proposed approach is validated by evaluating suitable grid operation metrics, such as technical constraint violations, hours of violations, Monte Carlo convergence criteria, required low‐voltage reinforcements, and the resulting feasible flexibility at the medium/low‐voltage interface across multiple future scenarios through exemplary case studies that demonstrate its efficacy.
Pisano et al. (Thu,) studied this question.