Tuesday’s disruption to the national electricity grid has been traced to a voltage disturbance at the Gombe Transmission Substation, the Nigerian Independent System Operator (NISO) has said.

In a statement issued on Tuesday to provide updates on repair and restoration efforts, the system operator clarified that the incident did not amount to a total system collapse, contrary to reports by some media organisations.

According to NISO, the disturbance originated at the Gombe Transmission Substation before spreading to other parts of the transmission network. The incident marked the second grid disturbance recorded in 2026.

Electricity supply across the affected areas has since been fully restored following immediate corrective actions by NISO’s technical teams.

“The national grid has been fully restored, and electricity supply across the affected areas has since returned to normal,” the statement said.

NISO added: “The incident only affected part of the national grid; therefore, it was not a total collapse.”

The operator explained that the event was accompanied by the tripping of some transmission lines and generating units, resulting in what it described as a partial system collapse.

The statement noted that the voltage disturbance rapidly propagated across the transmission network, affecting multiple substations beyond Gombe before stabilisation measures were implemented.

Specifically, the disturbance spread to the Jebba Transmission Substation and the Kainji Transmission Substation, while the Ayede Transmission Substation also experienced disruptions as the incident cascaded through the network.

NISO said restoration efforts commenced shortly after the disturbance was detected and were completed within hours. Although corrective actions were immediately deployed to stabilise the system and restore normal grid operations, some transmission lines and generating units tripped during the incident.

Nigeria’s power grid has continued to experience recurring disturbances in recent years. In 2025 alone, the national grid collapsed multiple times, with the last recorded incident occurring on December 29.

Tuesday’s disturbance represents the second grid collapse recorded in 2026. The latest incident was classified as a partial system collapse, with power generation dropping to zero megawatts at about 11:00 a.m.