Southeast Blackout Not Grid Failure: Transmission Fault Fixed, NISO Says

The Nigerian Independent System Operator (NISO), Nigeria’s grid operator, has clarified that last Thursday’s Southeast blackout was not a national system collapse but a localised transmission issue that was swiftly resolved.
NISO’s management stated that its “attention has been drawn to certain media reports, alleging that a ‘system collapse’ occurred at approximately 11:54hrs… resulting in a total blackout across the South-East region.”
“No system collapse occurred on the Nigerian National Grid on the said date and time,” the system operator reiterated.
According to NISO, “at approximately 11:47hrs, a protection trip was recorded on some 330kV transmission lines around the Onitsha Transmission Station,” which “led to a temporary and localised outage affecting certain areas supplied through the impacted transmission corridors, including portions of the Enugu Electricity Distribution Company (EEDC) and Port Harcourt Electricity Distribution Company (PHED) networks.”
The grid “remained stable and fully operational,” NISO added, noting that “generation across other regions was not disrupted,” “system frequency remained within acceptable operational limits,” and there was “no widespread loss of synchronism or nationwide blackout.”
It confirmed: “Affected transmission lines have since been restored, and supply reinstated to the impacted locations.”
Acknowledging inconveniences, the statement urged “stakeholders, media organizations, and members of the public to desist from rumors and rely only on verified technical updates from NISO,” described as “the only authentic source of information on all grid events.”NISO concluded: ”
The Nigerian National Grid remains operational and under continuous technical supervision to ensure reliability, resilience, and system security.”