The Coordinating Body of the National Interconnected Electric System (OC-SENI) in the Dominican Republic has concluded its technical investigation into the nationwide blackout that occurred on November 11. The comprehensive report, now available on the agency’s website, was completed within the same month of the incident—a notably faster turnaround compared to similar investigations in countries like Spain or Chile, which can take up to five months. The inquiry was conducted by a multidisciplinary team, underscoring the urgency and thoroughness of the process. The blackout originated at the 138 kV San Pedro de Macorís I substation, where a manual disconnection of a live line caused a high-intensity short circuit. Although protection systems responded immediately, the fault led to the disconnection of several nearby lines, isolating 575 MW of generation in the eastern region from the grid. This imbalance triggered automatic shutdowns of major power plants as part of their safety mechanisms. While SENI managed to stabilize system frequency within 89 seconds, the grid’s vulnerability, due to the lack of synchronized cold reserve capacity and incomplete replacement of EDAC circuits, resulted in a sudden frequency collapse and total system shutdown. The OC-SENI report not only details the sequence of events but also proposes corrective measures to bolster grid resilience. These include installing additional protections in double-bus substations, enhancing operational protocols to integrate thermal and renewable technologies, incorporating battery-based storage for auxiliary services and black-start capability, adjusting protection settings and automatic disconnection schemes, and reviewing high-frequency criteria in generation plants. The Coordinating Body is now focused on overseeing the implementation of these recommendations to improve the efficiency, safety, and reliability of the SENI.
Manual line disconnection triggered nationwide blackout, report says
