Manual energized disconnection caused the national blackout, according to OC-SENI report

Santo Domingo.- The Organismo Coordinador del Sistema Eléctrico Nacional Interconectado (OC-SENI) presented the technical report on the national blackout of November 11, in which it concludes that the failure originated in the 138 kV substation of San Pedro de Macorís I, after the manual disconnection of a line that was still energized. According to the document, this maneuver caused a high-intensity short circuit that immediately activated the protection systems and triggered a series of cascading events. Several nearby lines were automatically disconnected to isolate the fault, leaving the generation of the East (about 575 MW) isolated, which caused a strong imbalance between supply and electrical demand.

You may be interested in: http://Energía y Minas entregará informe sobre el apagón nacional la próxima semana

As a result, several large-capacity plants automatically tripped to protect themselves, weakening the system. Although the SENI managed to stabilize the frequency in the first few seconds, the lack of synchronized cold reserve and the incomplete restoration of the EDAC circuits caused a new abrupt frequency drop that ended up completely collapsing the system. The OC-SENI highlighted that the investigation was carried out with speed and technical rigor, concluding within the same month of the incident, unlike other countries where similar processes take up to five months. The report also includes a series of corrective measures, including the installation of additional protections in double-bus substations, operational adjustments for new generation technologies, integration of battery storage systems, review of protection actuation times, and verification of high-frequency criteria in several power plants. The entity assured that it remains in permanent session, following up on the fulfillment of these actions and working together with companies in the sector to strengthen the operation, security, and efficiency of the SENI.