An operating area comprises a set of substations, generation and demand resources that present some electrical restriction that limit exchanges with the rest of the system. The National Interconnected System (SIN) Technical Parameters Document lists the operating areas that make up the SIN. The National Dispatch Center (CND) recommends, for the National Operation Council’s (CNO) approval, modifications to the operating areas, when necessary, according to changes in the configuration of the SIN. (Source: Res. CREG-025-1995; Annex)