Flexibility needs assessment for distribution networks

Flexibility needs assessment (FNA) refers to the amount of flexibility DSO needs to plan or procure from the flexibility market to avoid probable DNI. The probable DNI are captured using modeling uncer- tainties using generated scenarios that emulate the different realizations which could happen. The scenario generation utilizes the nodal load and generation forecast along with historical forecast errors. Flexibility needs assessment optimal power flow (FNA-OPF) problem is solved for each of the scenarios. The robust FNA, considering the worst-case scenario, if used for flexibility procurement would lead to substantial over-procurement. In order to avoid this, a risk-based index, e.g. a chance constraint (CC), is introduced for procurement. Higher values of the chance constraint would project on to greater risk DSO might have to encounter by facing unresolved DNI. DNI in low voltage grids are often a local problem in which flexible resources in the proximity respond to avoid these incidents. To that end we cluster distribution grids onto connected zones, extend the local search for flexibility resources and propose a zonal bid selection framework that selects flexibility bids from neighborhoods to avoid DNI.